MPLX LP (Form: 8-K, Received: 12/10/2015 16:50:51)

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

_____________________________________________

FORM 8-K

_____________________________________________

Current Report

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of Report (Date of earliest event reported) December 4, 2015

_____________________________________________

MPLX LP

(Exact name of registrant as specified in its charter)

_____________________________________________




Delaware	001-35714	27-0005456
(State or other jurisdiction of incorporation)	(Commission File Number)	(IRS Employer Identification No.)



200 E. Hardin Street Findlay, Ohio		45840
(Address of principal executive offices)		(Zip Code)

Registrant’s telephone number, including area code:

(419) 672-6500

(Former name or former address, if changed since last report)

_____________________________________________

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:



¨	Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)



¨	Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)



¨	Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))



¨	Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))



Item 1.01	Entry into a Material Definitive Agreement.

On December 4, 2015, MPLX LP, a Delaware limited partnership (“MPLX”), entered into a loan agreement (the “Loan Agreement”) with MPC Investment LLC, a Delaware limited liability company (“MPC Investment”). Under the terms of the Loan Agreement, MPC Investment will make a loan or loans (the “Loan”) to MPLX on a revolving basis as requested by MPLX and as agreed to by MPC Investment, in an amount or amounts that do not result in the aggregate principal amount of all loans outstanding exceeding $500 million at any one time. The entire unpaid principal amount of the Loan, together with all accrued and unpaid interest and other amounts, shall become due and payable on December 4, 2020. MPC Investment may demand payment of all or any portion of the outstanding principal amount of the Loan, together with all accrued and unpaid interest and other amounts, at any time prior to December 4, 2020. Interest shall accrue on the unpaid principal amount of the Loan at a rate equal to the sum of (i) the one month term, LIBOR Rate for dollar deposits, plus (ii) a premium of one hundred fifty basis points.

The foregoing description of the Loan Agreement does not purport to be complete and is subject to, and qualified in its entirety by, the full text of the Loan Agreement, which is attached hereto as Exhibit 10.1 to this Current Report on Form 8-K and is incorporated herein by reference.

MPC Investment is the sole member of MPLX GP LLC, a Delaware limited liability company and the general partner of MPLX (“MPLX GP”), and is a wholly owned subsidiary of Marathon Petroleum Corporation, a Delaware corporation (“MPC”). As MPLX’s general partner, MPLX GP manages MPLX’s operations and activities through MPLX GP’s officers and directors. Certain individuals serve as officers and directors of both MPLX GP and MPC. In addition, as of the date hereof, MPC holds, indirectly through its subsidiaries, 56,932,134 common units representing limited partner interests in MPLX (“MPLX Common Units”) and 6,800,475 general partner units of MPLX, representing, respectively, 19.2% of the MPLX Common Units outstanding and a 2% general partner interest in MPLX.



Item 2.01	Completion of Acquisition or Disposition of Assets.

On December 4, 2015, MPLX completed the acquisition of MarkWest Energy Partners, L.P., a Delaware limited partnership (“MarkWest”), pursuant to the terms of the Agreement and Plan of Merger, dated as of July 11, 2015 (the “Original Merger Agreement”), as amended on November 10, 2015 (“Amendment No. 1”) and November 16, 2015 (“Amendment No. 2”; and the Original Merger Agreement as amended by Amendment No. 1 and Amendment No. 2, the “Merger Agreement”), by and among MPLX, MarkWest, MPLX GP, Sapphire Holdco LLC, a Delaware limited liability company and wholly owned subsidiary of MPLX (“Merger Sub”), and, for certain limited purposes set forth in the Merger Agreement, MPC. Under the terms of the Merger Agreement, Merger Sub merged with and into MarkWest (the “Merger”), with MarkWest surviving the Merger as a wholly owned subsidiary of MPLX.

At the effective time of the Merger on December 4, 2015 (the “Effective Time”), each outstanding common unit of MarkWest (the “MWE Common Units”) was converted into the right to receive (i) 1.09 MPLX Common Units (such consideration, the “Common Unit Merger Consideration”) and (ii) $6.20 in cash (the “Cash Consideration” and, together with the Common Unit Merger Consideration, the “Common Merger Consideration”).

At the Effective Time, each Class B unit of MarkWest (the “MWE Class B Units”) outstanding immediately prior to the Effective Time was converted into the right to receive one Class B unit of MPLX (the “MPLX Class B Units”) having substantially similar rights, including with respect to conversion and registration rights and obligations that the MWE Class B Units had immediately prior to the Effective Time. On July 1, 2016 and July 1, 2017 (unless earlier converted upon certain fundamental changes regarding MPLX), each MPLX Class B Unit will automatically convert into 1.09 MPLX Common Units and the right to receive the Cash Consideration.

At the Effective Time, the Class A units of MarkWest (the “MWE Class A Units”) outstanding immediately prior to the Effective Time were converted into a specified number of Class A units of MPLX (the “MPLX Class A Units”) having substantially similar rights and obligations that the MWE Class A Units had immediately prior to the Effective Time.

As a result of the Merger, each phantom unit representing MWE Common Units granted under MarkWest’s equity plans outstanding immediately prior to the Effective Time fully vested and converted into the right to receive the Common Merger Consideration.

The foregoing description of the Merger Agreement and the Merger does not purport to be complete and is qualified in its entirety by reference to the Original Merger Agreement, Amendment No. 1 and Amendment No. 2, copies of which are attached as Exhibit 2.1, 2.2 and 2.3, respectively, to this Current Report on Form 8-K, each of which is incorporated herein by reference.



Item 2.03	Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant.

As a result of the completion of the Merger, as of the Effective Time, MPLX assumed an aggregate principal amount of $4.1 billion in senior notes issued by MarkWest and MarkWest Energy Finance Corporation consisting of: $750 million aggregate principal amount of 5.500% senior notes due February 15, 2023; $1.0 billion aggregate principal amount of 4.500% senior notes due July 15, 2023; $1.15 billion aggregate principal amount of 4.875% senior notes due December 1, 2024; and $1.2 billion aggregate principal amount of 4.875% senior notes due June 1, 2025 (collectively, the "MarkWest senior notes").

The MarkWest senior notes were all issued under an indenture, dated as of November 2, 2010, as supplemented and amended, by and among MarkWest, MarkWest Energy Finance Corporation, the subsidiary guarantors party thereto and Wells Fargo Bank, National Association, as the trustee. The MarkWest senior notes are the senior unsecured obligations of MarkWest. The indentures governing the MarkWest senior notes contain covenants that restrict the ability of MarkWest and its subsidiaries, with significant exceptions, to: borrow money; pay distributions or dividends on equity or purchase, redeem or otherwise acquire equity; make investments; use assets as collateral in other transactions; sell certain assets or merge with or into other companies; engage in transactions with affiliates; and engage in unrelated businesses. The indentures governing the MarkWest senior notes also contain customary events of default.

On November 19, 2015, MPLX announced that, in connection with the Merger, it had commenced offers to exchange any and all outstanding MarkWest senior notes for (1) up to $4.1 billion aggregate principal amount of new notes issued by MPLX having the same maturity and interest rates as the MarkWest senior notes and (2) cash. In addition, on the same date, MarkWest commenced consent solicitations from holders of each series of the MarkWest senior notes to amend the indentures governing the MarkWest senior notes to remove certain restrictive and reporting covenants and certain default provisions. The exchange offers and consent solicitations are set to expire on December 18, 2015, unless extended. On December 3, 2015, supplemental indentures were executed to amend the indentures governing the MarkWest senior notes to remove the majority of these restrictive covenants and certain default provisions. The supplemental indentures are effective upon execution but will only become operative upon consummation of the exchange offers and consent solicitations.

As previously disclosed, on October 27, 2015, MPLX entered into an amendment to its existing credit agreement to, among other things, increase the aggregate amount of revolving credit capacity under the credit agreement by $1.0 billion for total aggregate commitments of $2.0 billion. This amendment to MPLX’s existing credit facility became effective in connection with the closing of the Merger. In connection with the closing of the Merger, MarkWest's bank revolving credit facility was terminated and the approximately $943 million outstanding under MarkWest's bank revolving credit facility was repaid with $850 million of borrowings under MPLX's bank revolving credit facility and $93 million of cash.



Item 3.02	Unregistered Sales of Equity Securities.

In connection with the Merger, MPLX issued 28,554,313 MPLX Class A Units upon the conversion of 22,640,000 MWE Class A Units and 7,981,756 MPLX Class B Units upon the conversion of 7,981,756 MWE Class B Units. The MPLX Class A Units and MPLX Class B Units were issued in reliance upon an exemption from registration requirements under Section 4(a)(2) of the Securities Act of 1933.

In connection with the Merger, MPLX GP purchased 5,160,950 MPLX general partner units for approximately $168 million in cash to maintain its 2% general partner interest in MPLX. The general partner units were issued in reliance on an exemption from registration under Section 4(a)(2) of the Securities Act of 1933.



Item 5.02	Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

Effective December 4, 2015, pursuant to the terms of the Merger Agreement, MPC Investment, the sole member of MPLX GP, increased the size of the board of directors of MPLX GP (the “Board”) from ten members to twelve members and elected Frank

M. Semple and Michael L. Beatty as directors. Also effective December 4, 2015, the Board appointed Mr. Semple to an executive officer role as Vice Chairman of MPLX GP. As Mr. Semple also serves as an officer of MPLX GP, he will not receive compensation for his services as a director. As a non-employee director, Mr. Beatty will receive compensation in the same manner as MPLX GP’s other non-employee directors. The terms of non-employee director compensation were disclosed in MPLX’s Annual Report on Form 10-K for the year ended December 31, 2014, filed with the Securities and Exchange Commission on February 27, 2015.

Effective December 4, 2015, the Board appointed Nancy K. Buese, age 45, Executive Vice President and Chief Financial Officer of MPLX GP. In her new role, Ms. Buese serves as the principal financial officer of MPLX. Ms. Buese was appointed Chief Financial Officer of MarkWest Energy GP, L.L.C., a Delaware limited liability company and the general partner of MarkWest (“MarkWest GP”) in October 2006. Prior to her appointment as Chief Financial Officer of MarkWest GP, Ms. Buese served as Chief Accounting Officer of MarkWest since November 2005. Prior to joining MarkWest, Ms. Buese was the Chief Financial Officer for Experimental and Applied Sciences ("EAS") in Golden, Colorado. EAS is a wholly owned subsidiary of Abbott Laboratories. Prior to her employment at EAS, Ms. Buese was a Vice President with TransMontaigne Inc. in Denver, Colorado. Preceding this appointment, Ms. Buese was a Partner with Ernst & Young LLP. Ms. Buese received her bachelor's degree in accounting and business administration from the University of Kansas and is a licensed certified public accountant in the State of Colorado.

On September 14, 2015, Ms. Buese entered into a retention agreement (the “Buese Retention Agreement”) with Marathon Petroleum Company LP, a Delaware limited partnership and wholly owned subsidiary of MPC (“MPC LP”), which provides that Ms. Buese is eligible to receive the following compensation in connection with her employment with MPC LP or its affiliates: (1) an annual salary of $450,000 and annual market-based pay increases in accordance with company practices; (2) a retention bonus in the form of long- and short-term incentives, consisting of cash, phantom units representing MPLX Common Units and MPC restricted stock and (3) a cash bonus for the 2015 calendar year determined by the performance metrics established under the short-term incentive plan of an affiliate of MarkWest. Ms. Buese is also eligible to participate in the compensation and benefit programs of MPC LP or its affiliates, including the annual cash bonus program and long-term incentive compensation plan, as well as other benefit plans and programs such as health and life insurance, income protection by means of long-term and short-term disability and retirement and severance benefits plans.

Effective December 4, 2015, the Board appointed John C. Mollenkopf, age 54, Executive Vice President and Chief Operating Officer - MarkWest Operations of MPLX GP. In his new role, Mr. Mollenkopf serves as principal operating officer of MPLX respecting the MarkWest operations. Mr. Mollenkopf became the Chief Operating Officer of MarkWest GP in January 2011. Prior to this, he served as the Chief Operations Officer of MarkWest GP since October 2006. Prior to his appointment as Chief Operations Officer, Mr. Mollenkopf served as Senior Vice President, Southwest Business Unit, since January 2004 and as Vice President, Business Development since January 2003. Prior to these positions, he served as Vice President, Michigan Business Unit, of MarkWest GP since its inception in May 2002 and in various leadership positions of MarkWest or its affiliates since 1997. From 1983 to 1996, Mr. Mollenkopf worked for ARCO Oil and Gas Company, holding various positions in process and project engineering, as well as operations supervision. Mr. Mollenkopf received his bachelor's degree in mechanical engineering from the University of Colorado at Boulder.

On November 12, 2015, Mr. Mollenkopf entered into a retention agreement (the “Mollenkopf Retention Agreement”) with MPC LP which provides that Mr. Mollenkopf is eligible to receive the following compensation in connection with his employment with MPC LP or its affiliates: (1) an annual salary of $480,000 and annual market-based pay increases in accordance with company practices; (2) a retention bonus in the form of long- and short-term incentives, consisting of cash, phantom units representing MPLX Common Units and MPC restricted stock and (3) a cash bonus for the 2015 calendar year determined by the performance metrics established under the short-term incentive plan of an affiliate of MarkWest. Mr. Mollenkopf is also eligible to participate in the compensation and benefit programs of MPC LP or its affiliates, including the annual cash bonus program and long-term incentive compensation plan, as well as other benefit plans and programs such as health and life insurance, income protection by means of long-term and short-term disability and retirement and severance benefits plans.

Effective December 4, 2015, the Board appointed Paula L. Rosson, age 49, Senior Vice President and Chief Accounting Officer of MPLX GP. In her new role, Ms. Rosson serves as principal accounting officer of MPLX. Ms. Rosson was appointed as principal accounting officer of MarkWest GP in July 2011. She was appointed as a Senior Vice President of MarkWest GP in January 2014. Ms. Rosson previously served as Vice President of MarkWest GP from November 2006 through December 2013 and as Controller from November 2006 through July 2011. Prior to that, she served various executive roles with Fischer Imaging Corporation, including President/Chief Executive Officer and Chief Financial Officer in 2006 and Vice President/Controller from 2005 through 2006, served as the Assistant Controller at Teletech from 2003 through 2004, served last as the Controller of a division of Cenveo from 1999 through 2003 and held various positions in the audit practice of Ernst & Young LLP from 1989 through 1999. Ms. Rosson received her master’s degree in accounting and bachelor’s degree in accounting from Utah State University and is a licensed certified public accountant in the State of Colorado.

Ms. Rosson entered into a letter agreement with MPC, dated October 6, 2015 (the “Letter Agreement”), which provides that Ms. Rosson is eligible to receive the following compensation in connection with her employment with an affiliate or subsidiary of MPC: (1) a retention bonus in the form of long- and short-term incentives, consisting of cash and phantom units representing MPLX Common Units and (2) a cash bonus for the 2015 calendar year determined by the performance metrics established under the short-term incentive plan of an affiliate of MarkWest. Ms. Rosson also receives an annual base salary and is eligible to participate in the compensation and benefit programs of MPC LP or its affiliates, including the annual cash bonus program and long-term incentive compensation plan, as well as other benefit plans and programs such as health and life insurance, income protection by means of long-term and short-term disability and retirement and severance benefits plans.

Effective December 4, 2015, Timothy T. Griffith resigned from his position as principal financial officer of MPLX. Mr. Griffith will no longer serve as an officer of MPLX GP but will continue to serve as a director on the Board. Mr. Griffith continues to serve as Senior Vice President and Chief Financial Officer of MPC.

Effective December 4, 2015, John S. Swearingen was appointed Vice President, Crude Oil and Refined Products Pipelines of MPLX GP. In this role, Mr. Swearingen continues to serve as the principal operating officer of MPLX respecting pipeline operations. Mr. Swearingen also continues to serve as Senior Vice President, Transportation and Logistics of MPC.

Effective December 4, 2015, Ian D. Feldman resigned from his position as principal accounting officer of MPLX and continues to serve as a Controller.

Effective December 4, 2015, Joshua P. Hallenbeck was appointed Vice President, Finance and Treasurer of MPLX GP. Mr. Hallenbeck previously served as Vice President of Finance and Treasurer of MarkWest GP. Effective December 4, 2015, Thomas Kaczynski resigned as Vice President, Finance and Treasurer of MPLX GP. Mr. Kaczynski continues to serve as Vice President, Finance and Treasurer of MPC.

The foregoing descriptions of the Buese Retention Agreement, Mollenkopf Retention Agreement and Letter Agreement do not purport to be complete and are qualified in their entirety by the full text of the Buese Retention Agreement, Mollenkopf Retention Agreement and Letter Agreement, copies of which are attached as Exhibit 10.2, 10.3 and 10.4, respectively, to this Current Report on Form 8-K, each of which is incorporated herein by reference.



Item 5.03	Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year.

On December 4, 2015, MPLX GP executed Amendment No. 1 (the “Partnership Amendment”) to the First Amended and Restated Agreement of Limited Partnership of MPLX LP (the “Partnership Agreement”).

The Partnership Amendment amends the Partnership Agreement to provide for the issuance of new classes of limited partner interests designated as MPLX Class A Units and MPLX Class B Units and to provide for other amendments necessary to accommodate the creation of MPLX Class A Units and MPLX Class B Units and the Merger.

The foregoing description of the Partnership Amendment and the transactions contemplated thereby does not purport to be complete and is subject to, and qualified in its entirety by, the full text of the Partnership Amendment, which is attached hereto as Exhibit 3.1 to this Current Report on Form 8-K and is incorporated herein by reference.



Item 7.01	Regulation FD Disclosure.

On December 4, 2015, MPLX and MWE issued a joint press release announcing the completion of the Merger. A copy of the press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated herein by reference.



Item 9.01	Financial Statements and Exhibits.

(a) Financial Statements of Business Acquired.

(b) Pro Forma Financial Information.



	The financial statements of MarkWest and pro forma financial information of MPLX required to be filed under Item 9.01 of Form 8-K are included in MPLX’s Registration Statement on Form S-4 (Registration No. 333-206455) as filed with the SEC on August 18, 2015, and as amended on September 18, 2015 and October 8, 2015, and are incorporated herein by reference.

(d) Exhibits.



Exhibit Number		Description


2.1*		Agreement and Plan of Merger, dated as of July 11, 2015, by and among MPLX LP, Sapphire Holdco LLC, MPLX GP LLC, MarkWest Energy Partners, L.P. and, for certain limited purposes set forth therein, Marathon Petroleum Corporation (incorporated by reference to Exhibit 2.1 to MPLX LP’s Current Report on Form 8-K (File No. 001-35714) filed with the Securities and Exchange Commission on July 13, 2015).
2.2		Amendment to Agreement and Plan of Merger, dated as of November 10, 2015, by and among MPLX LP, Sapphire Holdco LLC, MPLX GP LLC, MarkWest Energy Partners, L.P. and, for certain limited purposes set forth therein, Marathon Petroleum Corporation (incorporated by reference to Exhibit 2.1 to MPLX LP’s Current Report on Form 8-K (File No. 001-35714) filed with the Securities and Exchange Commission on November 12, 2015).
2.3		Amendment Number 2 to Agreement and Plan of Merger, dated as of November 16, 2015, by and among MPLX LP, Sapphire Holdco LLC, MPLX GP LLC, MarkWest Energy Partners, L.P. and, for certain limited purposes set forth therein, Marathon Petroleum Corporation (incorporated by reference to Exhibit 2.1 to MPLX LP’s Current Report on Form 8-K (File No. 001-35714) filed with the Securities and Exchange Commission on November 17, 2015).
3.1		Amendment No. 1 to the First Amended and Restated Agreement of Limited Partnership of MPLX LP, dated December 4, 2015.
10.1		Loan Agreement, by and between MPLX LP and MPC Investment LLC, dated December 4, 2015.
10.2		Retention Agreement, by and between Marathon Petroleum Company LP and Nancy K. Buese, dated September 14, 2015.
10.3		Retention Agreement, by and between Marathon Petroleum Company LP and John C. Mollenkopf, dated November 12, 2015.
10.4		Letter Agreement, by and between Marathon Petroleum Corporation and Paula L. Rosson, dated October 6, 2015.
23.1		Consent of Deloitte & Touche LLP, Independent Registered Public Accounting Firm of MarkWest.
99.1		Press release of MPLX LP and MarkWest Energy Partners, L.P. dated December 4, 2015.
* Certain schedules and exhibits to this agreement have been omitted pursuant to Item 601(b)(2) of Regulation S-K. A copy of any omitted schedule and/or exhibit will be furnished supplementally to the SEC upon request.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.



	MPLX LP

	By:	MPLX GP LLC, its General Partner


Date: December 10, 2015	By:	/s/ Nancy K. Buese
		Name: Nancy K. Buese
		Title: Executive Vice President and Chief Financial Officer

Index to Exhibits



Exhibit Number		Description


2.1*		Agreement and Plan of Merger, dated as of July 11, 2015, by and among MPLX LP, Sapphire Holdco LLC, MPLX GP LLC, MarkWest Energy Partners, L.P. and, for certain limited purposes set forth therein, Marathon Petroleum Corporation (incorporated by reference to Exhibit 2.1 to MPLX LP’s Current Report on Form 8-K (File No. 001-35714) filed with the Securities and Exchange Commission on July 13, 2015).
2.2		Amendment to Agreement and Plan of Merger, dated as of November 10, 2015, by and among MPLX LP, Sapphire Holdco LLC, MPLX GP LLC, MarkWest Energy Partners, L.P. and, for certain limited purposes set forth therein, Marathon Petroleum Corporation (incorporated by reference to Exhibit 2.1 to MPLX LP’s Current Report on Form 8-K (File No. 001-35714) filed with the Securities and Exchange Commission on November 12, 2015).
2.3		Amendment Number 2 to Agreement and Plan of Merger, dated as of November 16, 2015, by and among MPLX LP, Sapphire Holdco LLC, MPLX GP LLC, MarkWest Energy Partners, L.P. and, for certain limited purposes set forth therein, Marathon Petroleum Corporation (incorporated by reference to Exhibit 2.1 to MPLX LP’s Current Report on Form 8-K (File No. 001-35714) filed with the Securities and Exchange Commission on November 17, 2015).
3.1		Amendment No. 1 to the First Amended and Restated Agreement of Limited Partnership of MPLX LP, dated December 4, 2015.
10.1		Loan Agreement, by and between MPLX LP and MPC Investment LLC, dated December 4, 2015.
10.2		Retention Agreement, by and between Marathon Petroleum Company LP and Nancy K. Buese, dated September 14, 2015.
10.3		Retention Agreement, by and between Marathon Petroleum Company LP and John C. Mollenkopf, dated November 12, 2015.
10.4		Letter Agreement, by and between Marathon Petroleum Corporation and Paula L. Rosson, dated October 6, 2015.
23.1		Consent of Deloitte & Touche LLP, Independent Registered Public Accounting Firm of MarkWest.
99.1		Press release of MPLX LP and MarkWest Energy Partners, L.P. dated December 4, 2015.
* Certain schedules and exhibits to this agreement have been omitted pursuant to Item 601(b)(2) of Regulation S-K. A copy of any omitted schedule and/or exhibit will be furnished supplementally to the SEC upon request.

AMENDMENT NO. 1

FIRST AMENDED AND RESTATED

AGREEMENT OF LIMITED PARTNERSHIP OF

MPLX LP

This Amendment No. 1 (this “ Amendment ”) to the FIRST AMENDED AND RESTATED AGREEMENT OF LIMITED PARTNERSHIP OF MPLX LP, a Delaware limited partnership (the “ Partnership ”), dated effective as of October 31, 2012 (the “ Partnership Agreement ”), is entered into as of December 4, 2015 by MPLX GP LLC, a Delaware limited liability company (the “ General Partner ”), as the general partner of the Partnership. Capitalized terms used but not defined herein have the meanings given such terms in the Partnership Agreement.

RECITALS

WHEREAS, Section 5.6(a) of the Partnership Agreement provides that the Partnership may issue additional Partnership Interests (other than General Partner Interests (except for General Partner Interests issued pursuant to Section 5.2(b) )) and Derivative Partnership Interests for any Partnership Purpose at any time and from time to time to such Persons and for such consideration and on such terms and conditions as the General Partner shall determine, all without approval of any Limited Partners;

WHEREAS, Section 5.6(b) of the Partnership Agreement provides that Partnership Interests authorized to be issued by the Partnership pursuant to Section 5.6(a) of the Partnership Agreement may be issued in one or more classes, or one or more series of any such classes, with such designations, preferences, rights, powers and duties as shall be fixed by the General Partner;

WHEREAS, Section 13.1(g) of the Partnership Agreement provides that the General Partner, without the approval of any Partner, may amend any provision of the Partnership Agreement to reflect an amendment that the General Partner determines to be necessary or appropriate in connection with the authorization or issuance of any class or series of Partnership Interests pursuant to Section 5.6 of the Partnership Agreement;

WHEREAS, the Partnership has entered into an Agreement and Plan of Merger, dated as of July 11, 2015, as amended on November 10, 2015 and further amended on November 16, 2015 (the “ Merger Agreement ”), by and among the Partnership, the General Partner, MPC, Sapphire Holdco LLC, a Delaware limited liability company (“ Merger Sub ”), and MarkWest Energy Partners, L.P., a Delaware limited partnership (“ MarkWest ”), pursuant to which Merger Sub has agreed to be merged with and into MarkWest with MarkWest surviving as a wholly-owned subsidiary of the Partnership (“ MarkWest Merger ”);

WHEREAS, pursuant to the Merger Agreement, effective upon the MarkWest Merger, (i) the class A units representing limited partner interests in MarkWest (the “ MarkWest Class A Units ”) issued and outstanding immediately prior the MarkWest Merger are to convert into the right to receive a new class of units representing limited partner interests in the Partnership with substantially similar rights and obligations as the MarkWest Class A Units and (ii) the class B units representing

limited partner interests in MarkWest (the “ MarkWest Class B Units ”) issued and outstanding immediately prior the MarkWest Merger are to convert into the right to receive a new class of units representing limited partner interests in the Partnership with substantially similar rights and obligations as the MarkWest Class B Units;

WHEREAS, the General Partner has determined that the authorization and issuance of the Class A Units and Class B Units pursuant to the Merger Agreement complies with the requirements of the Partnership Agreement;

WHEREAS, the General Partner has determined, pursuant to Section 13.1(g) of the Partnership Agreement, that the amendments to the Partnership Agreement set forth herein are necessary or advisable in connection with the authorization and issuance of the Class A Units and the Class B Units;

WHEREAS, Sections 13.1(d)(i) and 13.1(d)(iv) of the Partnership Agreement provides that the General Partner may amend any provision of the Partnership Agreement without the approval of any Partner to reflect a change that the General Partner determines does not adversely affect the Limited Partners considered as a whole or any particular class of Partnership Interests as compared to other classes of Partnership Interests in any material respect or is required to effect the intent of the provisions of the Partnership Agreement;

WHEREAS, the General Partner has determined to effect this Amendment to provide for the creation of Class A Units and Class B Units and such other matters as are provided herein;

NOW, THEREFORE, in consideration of the premises set forth above, the General Partner hereby amends the Partnership Agreement as follows:

Section 1. Amendments .

(a) Section 1.1 . Section 1.1 of the Partnership Agreement is hereby amended to add, or to amend and restate, the following definitions:

“ Adjusted Capital Account ” means the Capital Account maintained for each Partner as of the end of each taxable period of the Partnership, (a) increased by any amounts that such Partner is obligated to restore under the standards set by Treasury Regulation Section 1.704-1(b)(2)(ii)(c) (or is deemed obligated to restore under Treasury Regulation Sections 1.704-2(g) and 1.704-2(i)(5)) and (b) decreased by (i) the amount of all losses and deductions that, as of the end of such taxable period, are reasonably expected to be allocated to such Partner in subsequent taxable periods under Sections 704(e)(2) and 706(d) of the Code and Treasury Regulation Section 1.751-1(b)(2)(ii), and (ii) the amount of all distributions that, as of the end of such taxable period, are reasonably expected to be made to such Partner in subsequent taxable periods in accordance with the terms of this Agreement or otherwise to the extent they exceed offsetting increases to such Partner’s Capital Account that are reasonably expected to occur during (or prior to) the taxable period in which such distributions are reasonably expected to be made (other than increases as a result of a minimum gain chargeback pursuant to Section 6.1(d)(i) or 6.1(d)(ii) ). The foregoing definition of Adjusted Capital Account is intended to comply with the provisions of Treasury Regulation Section 1.704-1

(b)(2)(ii)(d) and shall be interpreted consistently therewith. The "Adjusted Capital Account" of a Partner in respect of a General Partner Interest, a Common Unit, a Class A Unit, a Class B Unit, or any other specified interest in the Partnership shall be the amount which such Adjusted Capital Account would be if such General Partner Interest, Common Unit, a Class A Unit, Class B Unit or other interest in the Partnership were the only interest in the Partnership held by such Partner from and after the date on which such General Partner Interest, Common Unit, a Class A Unit, Class B Unit or other interest in the Partnership was first issued.

“ Adjusted Conversion Number ” means, with respect to each Class B Unit on any date of determination, the Conversion Number associated with such Class B Unit, multiplied by a fraction equal to the sum of (i) 1,000,000,000, divided by 1,050,000,000, plus (ii)(A)(I) one (1.00) minus (II) 1,000,000,000, divided by 1,050,000,000, multiplied by (B)(I) 80% with respect to the time period ending on but not including July 1, 2016, and (II) 100% with respect all the time periods beginning on or after July 1, 2016.

“ Amendment ” has the meaning assigned to such term in the preamble.

“ beneficial owner ” has the meaning assigned to such term in Rule 13d-3 and Rule 13d-5 under the Exchange Act, except that, in calculating the beneficial ownership of any particular “person” (as that term is used in Section 13(d)(3) of the Exchange Act), such “person” will be deemed to have beneficial ownership of all securities that such “person” has the right to acquire by conversion or exercise of other securities, whether such right is currently exercisable or is exercisable only after the passage of time and the term “ beneficially owned ” has a corresponding meaning.

“ Capital Account ” means the capital account maintained for a Partner pursuant to Section 5.5 . The “ Capital Account ” of a Partner in respect of a Common Unit, a Class A Unit, a Class B Unit or any other Partnership Interest shall be the amount which such Capital Account would be if such Common Unit, Class A Unit, Class B Unit or other Partnership Interest was the only interest in the Partnership held by such Partner from and after the date on which such Common Unit, Class A Unit, Class B Unit or other Partnership Interest was first issued.

“ Class A Unit ” means a Partnership Interest representing a fractional part of the Limited Partner Interests (but does not include Common Units, Subordinated Units or Class B Units), and having the rights and obligations specified with respect to Class A Units in this Agreement, which shall be identical to the rights and obligations of the Common Units except the Class A Units (i) will not have the right to vote on, approve or disapprove, or otherwise consent or not consent with respect to any matter (including mergers, share exchanges and similar statutory authorizations) except as otherwise required by any nonwaivable provision of law, and (ii) will not share in any Hydrocarbon Items or any Hydrocarbon Available Cash.

“ Class B Conversion Date ” means: (a) if a Fundamental Change Conversion does not occur prior to the date applicable to a series of Class B Units specified in this clause: (i) with respect to the Class B-1 Units, July 1, 2016; and (ii) with respect to the Class B-2 Units, July 1, 2017; and (b) if a Fundamental Change Conversion occurs at any time, with respect to each series of Class B Units that has not otherwise converted into Common Units prior to the date of

the consummation of such Fundamental Change, the date of the consummation of such Fundamental Change.

“ Class B Target Capital Amount ” means, with respect to an event triggering an adjustment to the Carrying Value of Partnership property pursuant to Section 5.5(d) upon which Class B Units are Outstanding, the product of (x) the then expected Per Unit Capital Amount of an Initial Common Unit following the revaluation resulting from such event times (y) the then Adjusted Conversion Number with respect to the Class B Units; provided that for periods beginning on or after July 1, 2016, such amount shall be reduced by an amount expected by the General Partner to prevent or reduce a disparity between the Per Unit Capital Amounts of the Initial Common Units and the Converted Common Units resulting from the conversion of the Class B-2 Units.

“ Class B Unit ” means a Partnership Interest representing a fractional part of the Partnership Interests of all Limited Partners (but does not include Common Units, Subordinated Units or Class A Units), and having the rights and obligations specified with respect to the Class B Units in this Agreement. The term “Class B Unit” includes Limited Partner Interests designated as Class B-1 Units and Class B-2 Units.

“ Class B Unitholder Fundamental Change Election ” has the meaning assigned to such term in Section 5.13(g)(ii) .

“ Class B-1 Units ” has the meaning assigned to such term in Section 5.13(b) .

“ Class B-2 Units ” has the meaning assigned to such term in Section 5.13(b) .

“ Common Unit ” means a Limited Partner Interest having the rights and obligations specified with respect to Common Units in this Agreement. The term “Common Unit” does not include a (a) Subordinated Unit, (b) Class A Unit, or (c) Class B Unit prior to its conversion into a Common Unit pursuant to the terms hereof.

“ Control ” including the correlative terms “ Controlling ,” and “ Controlled by ” means the possession, direct or indirect, of the power to direct or cause the direction of the management and policies of a Person, whether through ownership of voting securities, by contract or otherwise.

“ Conversion Number ” means, with respect to any Class B Unit, one and nine hundredths (1.09) Common Units; provided that such number of Common Units shall be subject to appropriate adjustment pursuant to Section 5.13(i) .

“ Converted Common Unit ” means a Common Unit issued upon conversion of a Class B Unit pursuant to Section 5.13 .

“ Discounted Conversion Number ” means, with respect to any Class B-1 Unit or Class B-2 Unit, as of the date of the consummation of a Fundamental Change or any other applicable determination date, the fraction of a Common Unit set forth opposite the applicable series of Class B Units in the table attached to this Amendment as Exhibit B; provided that such fraction of a Common Unit shall be subject to appropriate adjustment pursuant to Section 5.13(i) .

“ Elective Fundamental Change ” means any of the following events: (a) any direct or indirect sale, lease, exchange, conveyance, transfer or other disposition (in one transaction or a series of related transactions) of all or substantially all of the Partnership’s assets to any third Person, unless immediately following such sale, lease, exchange, transfer or other disposition such assets are owned, directly or indirectly, by the Partnership; or (b) a merger, consolidation, business combination, acquisition of Common Units or other transaction (i) the result of which is that, immediately after the consummation of such transaction, any Person (an “ Acquiring Person ”), other than the holders of the Common Units immediately prior to the consummation of such transaction, becomes the beneficial owner, directly or indirectly, of a majority of the Outstanding Common Units or, if the Partnership is not the surviving entity in such transaction, the majority of the outstanding voting securities of the surviving entity in such transaction or its parent entity and (ii) in which Partnership Interests that are beneficially owned by any Acquiring Person immediately after the consummation of such transaction, or if the Partnership is not the surviving entity in such transaction, the voting securities of the surviving entity or its parent entity that are beneficially owned by any Acquiring Person immediately after the consummation of such transaction, are not subject to the voting limitations set forth in clause (a) of the proviso of the definition of the defined term “Outstanding,” or any similar voting restrictions applicable to voting securities of the surviving entity or its parent entity in a transaction where the Partnership is not the surviving entity.

“ Equivalent Security ” has the meaning assigned to such term in Section 5.13(g)(ii) .

“ Final Class B Conversion Date ” means July 1, 2017, or, if a Fundamental Change Conversion occurs prior to such date, the date of the consummation of the applicable Fundamental Change.

“ Fundamental Change ” has the meaning assigned to such term in Section 5.13(g)(iii) .

“ Fundamental Change Conversion ” has the meaning assigned to such term in Section 5.13(g)(iii) .

“ General Partner ” has the meaning assigned to such term in the preamble.

“ Hydrocarbon Available Cash ” means all cash and cash equivalents on hand derived from or attributable to the Partnership’s ownership of, or sale or other disposition of, the shares of common stock of MarkWest Hydrocarbon, Inc. and all cash and cash equivalents on hand derived from Incremental Interest Income.

“ Hydrocarbon Items ” means the income, gains, losses, deductions and credits which are attributable to the Partnership’s ownership of, or sale or other disposition of, the shares of common stock of MarkWest Hydrocarbon, Inc. For the avoidance of doubt, for each taxable period, Hydrocarbon Items will include a portion of the interest income of the Partnership or its Affiliates from intercompany loans to MarkWest Hydrocarbon, Inc. corresponding to the amount of Incremental Interest Income but not the remaining interest income.

“ Incremental Interest Income ” means the interest income received by the Partnership or its Affiliates attributable to intercompany loans from the Partnership to MarkWest Hydrocarbon,

Inc., in excess of the amount of interest income received based on an interest rate equal to that rate applicable to the Partnership or its Affiliates under its loan facility in place at the time of the creation of the intercompany loan.

“ Limited Partner ” means, unless the context otherwise requires, each Initial Limited Partner, each additional Person that becomes a Limited Partner pursuant to the terms of this Agreement and any departing General Partner upon the change of its status from General Partner to Limited Partner pursuant to Section 11.3 , in each case, in such Person’s capacity as a limited partner of the Partnership; provided, however , that when the term “Limited Partner” is used herein in the context of any vote or other approval, including without limitation Articles XIII and XIV , such term shall not, solely for such purpose, include any holder of Class A Units or Class B Units except (a) with respect to Class B Units, as set forth in Section 5.13(d) or for purposes of Section 13.3(c) and (b) as may otherwise be required by any non-waivable provision of law.

“ Limited Partner Interest ” means the ownership interest of a Limited Partner in the Partnership, which may be evidenced by Common Units, Subordinated Units, Incentive Distribution Rights, Class A Units, Class B Units or other Partnership Interests or a combination thereof (but excluding Derivative Partnership Interests), and includes any and all benefits to which such Limited Partner is entitled as provided in this Agreement, together with all obligations of such Limited Partner pursuant to the terms and provisions of this Agreement; provided, however , that when the term “Limited Partner Interest” is used herein in the context of any vote or other approval, including without limitation Articles XIII and XIV , such term shall not, solely for such purpose, include any holder of Class A Units or Class B Units except (a) with respect to Class B Units, as set forth in Section 5.13(d) or for purposes of Section 13.3(c) and (b) as may otherwise be required by any non-waivable provision of law.

“ MarkWest ” has the meaning assigned to such term in the recitals.

“ MarkWest Class A Units ” has the meaning assigned to such term in the recitals.

“ MarkWest Class B Units ” has the meaning assigned to such term in the recitals.

“ MarkWest Merger ” has the meaning assigned to such term in the recitals.

“ M&R Group Member ” means M&R Liberty or any Person that is directly or indirectly Controlled by M&R Liberty.

“ M&R Liberty ” means M&R MWE Liberty, LLC, a Delaware limited liability company.

“ Merger Agreement ” has the meaning assigned to such term in the recitals.

“ Merger Sub ” has the meaning assigned to such term in the recitals.

“ Net Income ” means, for any taxable period, the excess, if any, of the Partnership’s items of income and gain (other than those items taken into account in the computation of Net Termination Gain or Net Termination Loss) for such taxable period over the Partnership’s items of loss and deduction (other than those items taken into account in the computation of Net Termination Gain

or Net Termination Loss) for such taxable period. The items included in the calculation of Net Income shall be determined in accordance with Section 5.5(b) and shall not include any items specially allocated under Section 6.1(d) or Section 6.1(e) ; provided , however , that the determination of the items that have been specially allocated under Section 6.1(d) shall be made without regard to any reversal of such items under Section 6.1(d)(xii) .

“ Net Loss ” means, for any taxable period, the excess, if any, of the Partnership’s items of loss and deduction (other than those items taken into account in the computation of Net Termination Gain or Net Termination Loss) for such taxable period over the Partnership’s items of income and gain (other than those items taken into account in the computation of Net Termination Gain or Net Termination Loss) for such taxable period. The items included in the calculation of Net Loss shall be determined in accordance with Section 5.5(b) and shall not include any items specially allocated under Section 6.1(d) or Section 6.1(e) ; provided , however , that the determination of the items that have been specially allocated under Section 6.1(d) shall be made without regard to any reversal of such items under Section 6.1(d)(xii) .

“ Net Termination Gain ” means, for any taxable period, the sum, if positive, of all items of income, gain, loss or deduction (determined in accordance with Section 5.5(b) ) that are (a) recognized by the Partnership (i) after the Liquidation Date or (ii) upon the sale, exchange or other disposition of all or substantially all of the assets of the Partnership Group, taken as a whole, in a single transaction or a series of related transactions (excluding any disposition to a member of the Partnership Group), or (b) deemed recognized by the Partnership pursuant to Section 5.5(d) ; provided , however , that the items included in the determination of Net Termination Gain shall not include any items of income, gain or loss specially allocated under Section 6.1(d) or Section 6.1(e) .

“ Net Termination Loss ” means, for any taxable period, the sum, if negative, of all items of income, gain, loss or deduction (determined in accordance with Section 5.5(b) ) that are (a) recognized by the Partnership (i) after the Liquidation Date or (ii) upon the sale, exchange or other disposition of all or substantially all of the assets of the Partnership Group, taken as a whole, in a single transaction or a series of related transactions (excluding any disposition to a member of the Partnership Group), or (b) deemed recognized by the Partnership pursuant to Section 5.5(d) ; provided , however , that the items included in the determination of Net Termination Loss shall not include any items of income, gain or loss specially allocated under Section 6.1(d) or Section 6.1(e) .

“ Outstanding ” means, with respect to Partnership Interests, all Partnership Interests that are issued by the Partnership and reflected as outstanding on the Partnership’s books and records as of the date of determination; provided, however, that:

(a) that if at any time any Person or Group (other than the General Partner or its Affiliates) beneficially owns 20% or more of the Partnership Interests of any class reflected as outstanding on the Partnership's books and records, all Partnership Interests owned by or for the benefit of such Person or Group shall not be entitled to be voted on any matter and shall not be considered to be outstanding when sending notices of a meeting of Limited Partners to vote on any matter (unless otherwise required by any non-waivable provision

of law), calculating required votes, determining the presence of a quorum or for other similar purposes under this Agreement, except that Partnership Interests so owned shall be considered to be outstanding for purposes of Section 11.1(b)(iv) (such Partnership Interests shall not, however, be treated as a separate class of Partnership Interests for purposes of this Agreement or the Delaware Act); provided further , that the foregoing limitation shall not apply (i) to any Person or Group who acquired 20% or more of the Partnership Interests of any class directly from the General Partner or its Affiliates (other than the Partnership), (ii) to any Person or Group who acquired 20% or more of the Partnership Interests of any class then reflected as outstanding in the Partnership's books and records directly or indirectly from a Person or Group described in clause (i), provided that, upon or prior to such acquisition, the General Partner shall have notified such Person or Group in writing that such limitation shall not apply, (iii) to any Person or Group who acquired 20% or more of any Partnership Interests issued by the Partnership with the prior approval of the Board of Directors, or (iv) with respect to Common Units beneficially owned by M&R Liberty or any other M&R Group Member or any Group of which M&R Liberty or any other M&R Group Member is a member, but the limitation set forth in clause (b) of this definition below shall apply to such Persons specified in this clause (iv); and

(b) if at any time M&R Liberty or any other M&R Group Member or any Group of which M&R Liberty or any other M&R Group Member is a member beneficially owns more than 5% of the Common Units that are then reflected as outstanding on the Partnership’s books and records as of the date of determination, then any Common Units owned by M&R Liberty or any other M&R Group Member or any such Group in excess of 5% of the Common Units that are then reflected as outstanding on the Partnership’s books and records as of the date of determination shall not be voted on any matter and shall not be considered to be “ Outstanding ” when calculating required votes, determining the presence of a quorum or for other similar purposes under this Agreement; provided, further, that the Board of Directors of the General Partner may waive the foregoing limitation in whole or in part from time to time. If the foregoing limitation applies at any time at which more than one M&R Group Member beneficially owns Common Units, then, each Record Holder of Common Units beneficially owned by any such M&R Group Member shall be deemed to hold a number of Common Units not subject to such limitation that is proportionate to the aggregate number of Common Units held by all such Record Holders.

“ Partnership ” has the meaning assigned to such term in the preamble.

“ Partnership Agreement ” has the meaning assigned to such term in the recital.

“ Partnership Fundamental Change Election ” has the meaning assigned to such term in Section 5.13(g)(i) .

“ Percentage Interest ” means, as of any date of determination, (a) as to the General Partner with respect to General Partner Units and as to any Unitholder with respect to Units, as the case may be, the product obtained by multiplying (i) 100% less the percentage applicable to clause (b) below by (ii) the quotient obtained by dividing (A) the number of General Partner Units held by the General Partner or the number of Units held by such Unitholder, as the case may be, by (B) the

total number of Outstanding Units and General Partner Units, and (b) as to the holders of other Partnership Interests issued by the Partnership in accordance with Section 5.6 for which a specific percentage is established as a part of such issuance, the percentage established as a part of such issuance. The Percentage Interest with respect to an Incentive Distribution Right shall at all times be zero. For all purposes of this Agreement, subject to the definition of Units, in making the calculation described in the preceding sentence, each Outstanding Class B Unit shall be deemed to be equal to a number of Units equal to the applicable Conversion Number, as of the applicable determination date.

“ Unit ” means a Partnership Interest that is designated by the General Partner as a “ Unit ” and shall include Common Units, Subordinated Units, Class A Units and Class B Units but shall not include (i) General Partner Units (or the General Partner Interest represented thereby) or (ii) Incentive Distribution Rights; provided, however , that when the term “Unit” is used herein in the context of any vote or other approval, including without limitation Article XIII and Article XIV , such term shall not, solely for such purpose, include any holder of Class A Units or Class B Units except (a) with respect to Class B Units, as set forth in Section 5.13(d) or for purposes of Section 13.3(c) and (b) as may otherwise be required by any non-waivable provision of law.

(b) Section 4.4(a) . Section 4.4(a) of the Partnership Agreement is hereby amended and restated as follows:

(i) “(a) The term “transfer,” when used in this Agreement with respect to a Partnership Interest, shall be deemed to refer to a transaction (i) by which the General Partner assigns all or any part of its General Partner Interest (represented by General Partner Units) to another Person and includes a sale, assignment, gift, pledge, encumbrance, hypothecation, mortgage, exchange or any other disposition by law or otherwise or (ii) by which the holder of a Limited Partner Interest assigns all or a part of such Limited Partner Interest to another Person who is or becomes a Limited Partner as a result thereof, and includes a sale, assignment, gift, exchange or any other disposition by law or otherwise, excluding a pledge, encumbrance, hypothecation or mortgage but including any transfer upon foreclosure of any pledge, encumbrance, hypothecation or mortgage. For purposes of Section 4.8(g) the term “transfer,” when used with respect to a Class B Unit shall be deemed to refer to a transaction by which the holder of such Class B Unit directly or indirectly assigns such Class B Unit to another Person, and includes (i) a sale, assignment, gift, pledge, encumbrance, hypothecation, mortgage, exchange or any other disposition by operation of law or otherwise and (ii) entry into any swap or other transaction or arrangement that transfers or that is designed to, or that might reasonably be expected to, result in the transfer to another Person, in whole or in part, any of the economic consequences of ownership of such Class B Unit.”

“(g) Section 4.8(g) .

(i) Notwithstanding anything to the contrary set forth in this Agreement, without the prior approval of the Board of Directors of the General Partner, M&R Liberty shall not transfer any Class B Units. Any subsequent transfer of Class B Units by a transferee so approved by the Board of Directors of the General Partner shall also require the prior written approval of the Board of Directors of the General Partner.

(ii) In addition to the foregoing, the Class B Units shall be subject to the restrictions on transfer set forth in Exhibit A .

(iii) For the avoidance of doubt, subject to the other restrictions set forth in this Section 4.8 , neither M&R Liberty nor any other M&R Group Member may in any case transfer Class B Units to an M&R Group Member if such transfer has as a purpose the avoidance of or is otherwise undertaken in contemplation of avoiding the restrictions on transfers in this Section 4.8(g) or elsewhere in this Agreement (it being understood that the purpose of this Section 4.8(g)(iii) is to prohibit the transfer of Class B Units to an M&R Group Member followed by a change in the relationship between the transferor and such M&R Group Member (or a change of control of such transferor or M&R Group Member) after the transfer, with the result and effect that the transferor has indirectly made a transfer of Class B Units by using an M&R Group Member, which transfer would not have been directly permitted under this Section 4.8(g) had such change in such relationship occurred prior to such transfer).

(iv) Upon reasonable request by the Partnership from time to time but no more often than quarterly, unless such a request is made in anticipation of any vote of the Record Holders of Units (or any class of Units), M&R Liberty and each other M&R Group Member who owns Units shall provide the Partnership with a written certification, signed by an executive officer of such Person (to the extent such Person is not a natural person), setting forth the number of Class B Units and the number of Common Units owned beneficially and of record by such Person. Each of M&R Liberty and each other M&R Group Member shall, upon the request of the Partnership, provide the Partnership with copies of records of any transfers of Class B Units or Common Units involving such Person.”

(d) Section 4.8(h) . Section 4.8 of the Partnership Agreement is hereby amended to add Section 4.8(h) to read as follows:

“(h) The transfer of Converted Common Units shall be subject to the restrictions imposed by Section 6.10 .”

(e) Section 5.2(b) . Section 5.2(b) of the Partnership Agreement is hereby amended and restated to read in its entirety as follows:

“(b) Upon the issuance of any additional Limited Partner Interests by the Partnership (other than (i) the Common Units issued pursuant to the Initial Public Offering, (ii) the Common Units and Subordinated Units issued pursuant to Section 5.3(a) , (iii) any Common Units issued pursuant to Section 5.11 and (iv) except as otherwise set forth in this Section 5.2(b) , any Common Units issued upon the conversion of any Partnership Interests), the

General Partner may, in order to maintain the Percentage Interest with respect to its General Partner Interest, make additional Capital Contributions in an amount equal to the product obtained by multiplying (A) the quotient determined by dividing (x) the Percentage Interest with respect to the General Partner Interests immediately prior to the issuance of such additional Limited Partner Interests by the Partnership by (y) 100% less the Percentage Interest with respect to the General Partner Interest immediately prior to the issuance of such additional Limited Partner Interests by the Partnership times (B) the gross amount contributed to the Partnership by the Limited Partners (before deduction of underwriters’ discounts and commissions) in exchange for such additional Limited Partner Interests. Any Capital Contribution pursuant to this Section 5.2(b) shall be evidenced by the issuance to the General Partner of a proportionate number of additional General Partner Units. Notwithstanding the foregoing and for the avoidance of doubt, with regard to the conversion of the Class B Units into Converted Common Units, this Section 5.2(b) and the General Partner’s right to make additional Capital Contributions shall be applicable upon the conversion of any Class B Unit to a Converted Common Unit pursuant to Section 5.13 , with the amount to be contributed by the General Partner being the amount necessary for the General Partner to have the same Percentage Interest after the conversion by reference to the then fair market value of a Common Unit.”

(f) Section 5.5(c) . Section 5.5(c) of the Partnership Agreement is hereby amended to add new Section 5.5(c)(iv) to read as follows:

“(iv) Class B Unit and Converted Common Unit Capital Accounts.

(A) Upon conversion of the Class B-1 Units and Class B-2 Units into Converted Common Units, the Capital Account maintained for the holder of such converted Class B Units with respect to its Class B Units will (1) first, be allocated to the Converted Common Units held by such holder in an amount equal to the product of (x) the number of such Converted Common Units and (y) the then Per Unit Capital Amount for an Initial Common Unit, and (2) second, any remaining balance in such Capital Account will be retained with respect to such holder’s remaining Class B Units.

(B) Subject to Section 6.10 , immediately prior to the transfer of a Converted Common Unit by a holder thereof, the Capital Account maintained for such Person with respect to its Class B Units or Converted Common Units will (1) first, be allocated to the Converted Common Units to be transferred in an amount equal to the product of (x) the number of such Converted Common Units to be transferred and (y) the Per Unit Capital Amount for an Initial Common Unit, and (2) second, any remaining balance in such Capital Account will be retained by the transferor, regardless of whether it has retained any Class B Units or Converted Common Units. Promptly following any such allocation, the transferor’s Capital Account, if any, maintained with respect to the retained Class B Units or retained Converted Common Units, if any, will have a balance equal to the amount allocated under clause (2) hereinabove, and the transferee’s Capital Account established with respect to the transferred Converted Common Units will have a balance equal to the amount allocated under clause (1) hereinabove.”

(g) Section 5.9(a) . Section 5.9(a) of the Partnership Agreement is hereby amended and restated to read as follows:

“(a) Subject to Section 5.9(e) , Section 5.13(i) , Section 6.6 and Section 6.9 (dealing with adjustments of distribution levels), the Partnership may make a Pro Rata distribution of Partnership Interests to all Record Holders or may effect a subdivision or combination of Partnership Interests so long as, after any such event, each Partner shall have the same Percentage Interest in the Partnership as before such event, and any amounts calculated on a per Unit basis (including any Common Unit Arrearage or Cumulative Common Unit Arrearage) or stated as a number of Units (including the number of Subordinated Units that may convert prior to the end of the Subordination Period and the number of Common Units into which Class B Units may convert) are proportionately adjusted.”

(h) Article V; Section 5.12 . Article V of the Partnership Agreement is hereby amended to add a new Section 5.12 creating a new class of Units to read as follows:

“Section 5.12 Establishment of Class A Units .

(a) Designation . There is hereby created a class of Units designated as “Class A Units” with the designations, preferences and relative, participating, optional or other special rights, powers and duties as set forth in this Section 5.12 .

(b) Series . The Class A Units authorized pursuant to Section 5.12(a) are all designated as a single series of Class A Units.

(c) Distributions . The Class A Units shall have the right to participate in distributions with Common Units, Pro Rata, except that Class A Units will not share in any Hydrocarbon Available Cash.

(d) Voting Rights . The Class A Units shall not be entitled to vote on, approve or disapprove, or otherwise consent or not consent with respect to any matter (including mergers, share exchanges and similar statutory authorizations) except as otherwise required by any nonwaivable provision of law.

(e) Registrar and Transfer Agent . The Class A Units shall be recorded in the Partnership Register and ownership of the Class A Units shall be evidenced by book entry notation in the Partnership Register.”

(i) Article V; Section 5.13 . Article V of the Partnership Agreement is hereby amended to add a new Section 5.13 creating a new class of Units to read as follows:

“Section 5.13 Establishment of Class B Units .

(a) Designation . There is hereby created a class of Units designated as “Class B Units” and consisting of a total of 7,981,756 Class B Units, with the designations, preferences and relative, participating, optional or other special rights, powers and duties as set forth in this Section 5.13 .

(b) Series . Of the aggregate number of Class B Units authorized pursuant to Section 5.13(a) , 3,990,878 are designated as “ Class B-1 Units ” and 3,990,878 are designated as “ Class B-2 Units. ”

(c) Distributions . Prior to its conversion into a Common Unit in accordance with Section 5.13(f) or Section 5.13(g) , and notwithstanding any provision of this Agreement to the contrary, a Class B Unit shall not be entitled to receive any distributions pursuant to this Agreement.

(d) Voting Rights . The Class B Units prior to conversion shall not be entitled to (i) vote with the Common Units as a single class on any matters on which holders of Common Units are entitled to vote (including the matters described in Section 5.13(g)(iv)(B) ) or (ii) vote as a separate class on any matters; provided that, notwithstanding the foregoing, but without limiting the General Partner’s authority to adopt amendments to this Agreement without the approval of any Partners or Assignees as contemplated in Section 13.1 , the Class B Units shall be entitled to vote as a separate class on any matter that disproportionately and adversely affects the rights or preferences of the Class B Units in relation to other classes of Partnership Interests, including matters subject to Section 13.3(c) that meet the foregoing requirement, but in each case subject to Section 14.3 , and such separate class vote shall apply to matters otherwise approved pursuant to Section 13.3(d) or Section 13.3(e) solely to the extent they disproportionately and adversely affect the rights or preferences of the Class B Units in relation to other classes of Partnership Interests. The approval of a majority of the Class B Units shall be required to approve any matter for which the holders of the Class B Units are so entitled to vote as a separate class. For such matters Class B Units are entitled to vote upon, each Class B Unit will be entitled to the number of votes equal to the number of Common Units into which a Class B Unit is convertible pursuant to Section 5.13(f) at the time of the record date for the vote or written consent on the matter.

(e) Registrar and Transfer Agent/Certificates . The Class B Units shall be recorded in the Partnership Register and the ownership of the Class B Units (including the restrictions on transfer set forth in Exhibit A ) shall be evidenced by book entry notation in the Partnership Register.

(f) Conversion . Except as provided in this Section 5.13(f) and Section 5.13(g) , the Class B Units are not convertible into Common Units. Each Outstanding Class B-1 Unit and Class B-2 Unit shall automatically convert into a number of Common Units equal to the Conversion Number on the applicable Class B Conversion Date without any further action by the holders thereof. The terms of a Class B Unit will be changed, automatically and without further action, on the applicable Class B Conversion Date so that such Class B Unit is converted into a number of Common Units equal to the Conversion Number on such Class B Conversion Date and, immediately thereafter, such Class B Unit shall not be Outstanding; provided , however , that each Converted Common Unit will become Outstanding and will remain subject to the provisions of Section 6.1(d)(x) and Section 6.10 .

(g) Fundamental Change .

(i) The Partnership may elect (a “ Partnership Fundamental Change Election ”) to convert all, but not less than all, of the Class B Units into Common Units immediately prior to the consummation of an Elective Fundamental Change subject to the terms and conditions of this Section 5.13(g) . If the Partnership desires to make a Partnership Fundamental Change Election it shall, not less than 15 days prior to the date of the expected consummation of an Elective Fundamental Change, send a written notice to each holder of Class B Units: (A) describing the transaction or transactions that constitute such Elective Fundamental Change; (B) stating the expected date of consummation of such Elective Fundamental Change and the Partnership’s computation of the number of Common Units into which each Class B-1 Unit and Class B-2 Unit would be converted pursuant to a Fundamental Change Conversion on such expected consummation date; and (C) stating that the Partnership has made a Partnership Fundamental Change Election with respect to such Elective Fundamental Change. The Partnership may, by written notice to the holders of Class B Units, revoke a Partnership Fundamental Change Election at any time prior to the 15 ^th day prior to the date of the consummation of the applicable Elective Fundamental Change; provided, that the Partnership thereafter (or simultaneously therewith) timely sends the notice to the holders of Class B Units contemplated by Section 5.13(g)(ii) .

(ii) If the Partnership does not elect to timely make a Partnership Fundamental Change Election with respect to any Elective Fundamental Change or revokes such an election in accordance with Section 5.13(g)(i) , then the Partnership shall, not less than 15 days prior to the date of the consummation of an Elective Fundamental Change, send a written notice to each holder of Class B Units: (A) describing the transaction or transactions that constitute such Elective Fundamental Change; and (B) stating the expected date of consummation of such Elective Fundamental Change and the Partnership’s computation of the number of Common Units into which each Class B-1 Unit and Class B-2 Unit would be converted pursuant to a Fundamental Change Conversion on such expected consummation date. No later than ten days following delivery of the notice provided for in the previous sentence, the holders of Class B Units may, in their sole discretion, deliver to the Partnership a written notice executed by holders of a majority of the Class B Units, electing (a “ Class B Unitholder Fundamental Change Election ”) to convert all, but not less than all, of the Class B Units into Common Units immediately prior to the consummation of an Elective Fundamental Change subject to the terms and conditions of this Section 5.13(g) . Any notice from the holders of Class B Units so electing a Class B Unitholder Fundamental Change Election (x) shall be binding upon all holders of Class B Units and shall provide for the conversion of all Class B Units even if less than all of the Class B Units delivered the Class B Unitholder Fundamental Change Election, and (y) may be conditioned on consummation of the applicable Elective Fundamental Change on or prior to a date specified in such notice.

(iii) If (A) the Partnership timely makes and does not revoke a Partnership Fundamental Change Election in accordance with Section 5.13(g)(i) , (B) the holders

of the Class B Units timely make a Class B Unitholder Fundamental Change Election in accordance with Section 5.13(g)(ii) , or (C) the Partnership is to be dissolved in accordance with this Agreement (the event described in this clause (C), and any event constituting an Elective Fundamental Change, each a “ Fundamental Change ”), then, immediately prior to the consummation of the Fundamental Change, each Outstanding Class B-1 Unit and Class B-2 Unit shall convert (a “ Fundamental Change Conversion ”) into the number of Common Units equal to the applicable Discounted Conversion Number as of the date of the consummation of such Fundamental Change without any further action by the holders thereof. The terms of each Class B Unit will be changed, automatically and without further action, on the date of the consummation of such Fundamental Change so that each Class B Unit is so converted into such number of Common Units as of the date of the consummation of such Fundamental Change and, immediately thereafter, such Class B Unit shall not be Outstanding; provided , however , that each Converted Common Unit will become Outstanding and will remain subject to the provisions of Section 6.1(d)(x) .

(iv) For the avoidance of doubt, to the extent that a Fundamental Change Conversion occurs in respect of any Fundamental Change pursuant to this Section 5.13(g) , the Converted Common Units issued as a result thereof shall (A) be entitled to participate in such Fundamental Change on an as-converted basis and to receive the consideration to which a Common Unit is entitled upon the consummation of such Fundamental Change and (B) not have any right to vote in respect of such Fundamental Change or any related matter.

(h) Extraordinary Partnership Transactions . Except to the extent that any such event is a Fundamental Change in respect of which a Fundamental Change Conversion occurs pursuant to Section 5.13(g) , prior to the consummation of any merger, consolidation or other business combination in which the Partnership will not be the surviving entity, the Partnership shall make appropriate provision to ensure that the holders of Class B Units receive in such transaction a security, issued by the Person surviving or resulting from such transaction and containing provisions substantially equivalent to this Section 5.13 as determined reasonably in good faith by the General Partner and such other provisions of this Agreement as are applicable to the establishment of the designations, preferences, rights, powers and duties of the Class B Units (an “ Equivalent Security ”), including appropriate provision to ensure that the holders of Class B Units would be entitled to receive upon subsequent conversion of such Equivalent Security consideration equivalent to that which each holder of a Class B Unit would have been entitled if such Class B Unit had been converted into Common Units in connection with such Fundamental Change, with appropriate provision being made to account for the Discounted Conversion Numbers that would apply on any successive conversion of any such Equivalent Security.

(i) Distributions, Combinations, Subdivisions and Reclassifications by the Partnership . If, prior to the Final Class B Conversion Date, the Partnership: (A) makes a distribution on its Common Units in Common Units; (B) subdivides or splits its Common

Units into a greater number of Common Units; (C) combines or reclassifies its Common Units into a smaller number of Common Units; or (D) issues by reclassification of its Common Units any Partnership Interests (including any reclassification in connection with a merger, consolidation, or business combination in which the Partnership is the surviving entity), then the Conversion Number, each Discounted Conversion Number in effect at the time of the Record Date for such distribution or the effective date of such subdivision, split, combination or reclassification and all Discounted Conversion Numbers that may be applicable from time to time after such date, shall be proportionally adjusted based on the number of Common Units (or any Partnership Interests into which such Common Units would have been merged, consolidated or combined pursuant to clause (D) above) that a holder of one Class B Unit would have been entitled to receive had such Class B Unit been entitled to be (and had) converted, immediately prior to such Record Date or effective date, into a number of Common Units (or any Partnership Interests into which such Common Units would have been merged, consolidated or combined pursuant to clause (D) above) equal to the Conversion Number then in effect. An adjustment made pursuant to this Section 5.13(i) shall become effective immediately after the Record Date in the case of a distribution and shall become effective immediately after the effective date in the case of a subdivision, split, combination or reclassification. Adjustments shall be made successively pursuant to this Section 5.13(i) whenever any event described in this Section 5.13(i) shall occur. Notwithstanding the foregoing, no adjustment would be made pursuant to clause (D) above in respect of any Fundamental Change where the Partnership or the holders of Class B Units elect to convert the Class B Units into Common Units in connection with such Fundamental Change.

(j) No Fractional Converted Common Units . Notwithstanding anything in this Section 5.13 , no fractional Common Units shall be issued upon any conversion of Class B Units into Converted Common Units in accordance with Section 5.13(f) or Section 5.13(g) . All Common Units (including fractions thereof) issuable upon conversion of more than one Class B Unit by a holder thereof shall be aggregated for purposes of determining whether the conversion would result in the issuance of any fractional unit. If, after the aforementioned aggregation, the conversion would result in the issuance of a fraction of a Common Unit, the Partnership shall, in lieu of issuing any fractional unit, at the Partnership’s option, either round each fractional Unit to the nearest whole Unit (and a 0.5 Unit shall be rounded to the next higher Unit) or pay the holder otherwise entitled to such fractional Unit a sum in cash determined by reference to the Current Market Price of a Common Unit on the date of such conversion.

(k) Surrender of Certificates . Subject to the requirements of Section 6.10 , upon a conversion of Class B Units into Common Units in accordance with Section 5.13(f) or Section 5.13(g) , the Partnership shall, as soon as practicable thereafter, issue and deliver at such office, to such holder of Class B Units, one or more certificates, registered in the name of such holder, or other evidence of the issuance of uncertificated certificates, for the number of Common Units and, if applicable, Class B Units, to which such holder shall then be entitled. Such a conversion shall be deemed to have been made as of the applicable Class B Conversion Date, and the Person entitled to receive the Common Units issuable upon such

conversion shall be treated for all purposes as the record holder of such Common Units as of such date.

(l) Initial Capital Account . The Capital Account with respect to each Class B Unit as of December 4, 2015 shall equal the Class B Target Capital Amount as of such date.”

(j) Section 6.1(a) . Section 6.1 of the Partnership Agreement is hereby amended to amend and restate in its entirety the introductory language in Section 6.1 to read as follows:

“ Allocations for Capital Account Purposes . For purposes of maintaining the Capital Accounts and in determining the rights of the Partners among themselves, the Partnership's items of income, gain, loss and deduction (computed in accordance with Section 5.5(b) ) for each taxable period shall be allocated among the Partners as provided herein, including, but not limited to, the limitations provided in Section 6.1(e) .”

(k) Section 6.1(c)(ii)(B) . Section 6.1(c)(ii)(B) is hereby amended and restated to read as follows:

(B) “Second, (x) to the General Partner in accordance with its Percentage Interest and (y) to all Unitholders, Pro Rata, a percentage equal to 100% less the General Partner’s Percentage Interest, until the Capital Account in respect of each Unit then Outstanding has been reduced to zero;”

(l) Section 6.1(c)(v) . Section 6.1(c) is hereby amended to add a new Section 6.1(c)(v) to read as follows:

“(v) As provided in Section 6.1(e) , items of income and gain allocated under the foregoing provision of Section 6.1(c)(i) , 6.1(c)(ii) , 6.1(c)(iii) , or 6.1(c)(iv) that are Hydrocarbon Items shall be allocated solely to Unitholders other than the holders of Class A Units (and, within each Class of Units, Pro Rata as provided in such subsections).”

(m) Section 6.1(c)(vi) and (vii) . Section 6.1(c) is hereby amended to add new Sections 6.1(c)(vi) and (vii) to read as follows:

“(vi) For the avoidance of doubt and consistent with Section 6.1(e) , if on the Liquidation Date the Partnership owns any shares of MarkWest Hydrocarbon, Inc. or there are any Hydrocarbon Items for the period ending on the Liquidation Date, the allocations required under Section 6.1(c) will (i) first be performed with respect to any gain or loss of the Partnership that is not attributable to Hydrocarbon Items, and (ii) then performed a second time with respect to any remaining Net Termination Gains or Net Termination Losses.

(vii) Notwithstanding any other provision hereof, no amounts of income, gain, loss, expense or deduction shall be allocated to any Class B Units pursuant to Sections 6.1(c)(i) , (iii) or (iv) prior to the conversion of such Class B Units into Common Units, although amounts may be allocated to such units under Section 6.1(d)(x) .”

(n) Section 6.1(d)(x) . Section 6.1(d)(x) is hereby amended to add new Sections 6.1(d)(x)(E) , (F) , (G) , (H) , and (I) to read as follows:

“(x) Economic Uniformity .

(E) Except as addressed by Section 6.1(d)(x)(H) , with respect to an event triggering an adjustment to the Carrying Value of Partnership property pursuant to Section 5.5(d) when a disparity exists between the Per Unit Capital Amounts of the Initial Common Units and the Converted Common Units, any Unrealized Gains and Unrealized Losses shall be allocated among (x) the General Partner, in accordance with its Percentage Interest, and the holders of Common Units other than the Converted Common Units and holders of Class A Units, Pro Rata, a percentage equal to 100% less the General Partner’s Percentage Interest, and (y) the General Partner, in accordance with its Percentage Interest, and the holders of Converted Common Units a percentage equal to 100% less the General Partner’s Percentage Interest, in a manner that to the nearest extent possible results in the elimination of such disparity between the Per Unit Capital Amounts of the Initial Common Units and the Converted Common Units.

(F) With respect to an event triggering an adjustment to the Carrying Value of Partnership property pursuant to Section 5.5(d) when a disparity exists between the Per Unit Capital Amounts of a Class B Unit and the Class B Target Capital Amount at such time, any Unrealized Gains and Unrealized Losses shall be allocated among (x) the General Partner, in accordance with its Percentage Interest, and the holders of Common Units and holders of Class A Units, Pro Rata, a percentage equal to 100% less the General Partner’s Percentage Interest, and (y) the General Partner, in accordance with its Percentage Interest, and the holders of Class B Units, a percentage equal to 100% less the General Partner’s Percentage Interest, in a manner that to the nearest extent possible results in the elimination of such disparity between the Per Unit Capital Amounts of a Class B Unit and the Class B Target Capital Amount.

(G) At the election of the General Partner, with respect to any taxable period, all or a portion of the remaining items of Partnership gross income, gain, loss or deduction for such taxable period shall be allocated to each Partner holding Converted Common Units in the proportion of the number of Converted Common Units held by such Partner to the total number of Converted Common Units then Outstanding, until each such Partner has been allocated an amount of gross income or gain that increases the Capital Account maintained with respect to such Converted Common Units to an amount equal to the product of (A) the number of Converted Common Units held by such Partner and (B) the Per Unit Capital Amount of an Initial Common Unit. The purpose of this allocation is to establish uniformity between the Capital Accounts underlying Converted Common Units and those Capital Accounts underlying other Common Units immediately prior to the transfer or other disposition of a Converted Common Unit. This allocation method for establishing such economic uniformity will only be available to the General Partner if the method for allocating the Capital Account maintained with respect to the holder of Converted Common Units between the transferred and retained Converted Common Units pursuant to Section 5.5(c)

(iv) does not otherwise provide such economic uniformity to the transferred Converted Common Units.

(H) After the conversion of any Class B Units based upon the Discounted Conversion Number, all or a portion of the remaining items of Net Termination Loss, Net Loss, and if necessary gross loss and deduction, for the taxable period in which such conversion occurs shall be allocated 100% to Partners holding the Converted Common Units (which were converted based upon such Discounted Conversion Number) in the proportion of the number of such Converted Common Units held by such Partners, until each such Partner has been allocated the minimum amount necessary to reduce the Capital Account of each such Converted Common Unit to the Per Unit Capital Amount of an Initial Common Unit; provided that, to the extent possible, a portion of such allocation shall consist of gross operating loss equal to the lesser of (x) the aggregate amount of the incremental Section 704(c) income allocations allocated to the Class B Units converted based upon the Discounted Conversion Number for the current and prior taxable periods relating to the built-in gain value discrepancy between the Discounted Conversion Number and the Adjusted Conversion Number with respect to the Class B Units converted based upon the Discounted Conversion Number and (y) the aggregate amount of taxable income that has been allocated the Class B Units converted based upon the Discounted Conversion Number for the current and prior taxable periods.

(I) The provisions of this Section 6.1(d)(x) shall also be subject to the limitations and requirements of Section 6.10 , as applicable.”

(o) Section 6.1(d)(xiv) . Section 6.1(d) is hereby amended to add a new Section 6.1(d)(xiv) as follows:

“(xiv) Priority Allocations. If the amount of cash or the Net Agreed Value of any property distributed (except cash or property distributed pursuant to Section 12.4 ) to any Common Unitholder or Class A Unitholder with respect to its Units for a taxable year is greater (on a per Unit basis) than the amount of cash or the Net Agreed Value of property distributed to the Class B Unitholders with respect to their Class B Units (on a per Unit basis), then gross income in an amount equal to the product of 60%, multiplied by the aggregate amount of such distribution shall be allocated to the holders of Common Units and Class A Units, Pro Rata.”

(p) Section 6.1(d)(xv) . Section 6.1(d) is hereby amended to add a new Section 6.1(d)(xv) to read as follows:

“(xv) Certain Special Allocations. Items of income and gain allocated under the foregoing provisions of Section 6.1(d)(i) , 6.1(d)(ii) , 6.1(d)(iii) , 6.1(d)(iv) , 6.1(d)(ix) or 6.1(d)(x) that are Hydrocarbon Items shall, to the maximum extent possible, be allocated to the applicable Unitholders other than the holders of Class A Units, Pro Rata.”

(q) Article VI, Section 6.1(e) . Article VI of the Partnership Agreement is hereby amended to add new Section 6.1(e) to read as follows

“(e) Allocations to Class A Units . For purposes of this Agreement, including, but not limited to, the allocations under this Article VI, for each taxable period, all Hydrocarbon Items shall be allocated solely to the Unitholders other than the holders of Class A Units pursuant to this Agreement as if the Class A Units were not treated as Units or Common Units.”

(r) Section 6.3 . Section 6.3 of the Partnership Agreement is hereby amended to add a new Section 6.3(e) to read as follows:

“(e) For the avoidance of doubt, notwithstanding any provision of this Agreement to the contrary, a Class A Unit shall not be entitled to receive any distributions pursuant to this Agreement to the extent such distributions are attributable to Hydrocarbon Available Cash.”

(s) Section 6.4(b) . Section 6.4(b) of the Partnership Agreement is hereby amended and restated to read as follows:

“(b) After the Subordination Period . Available Cash with respect to any Quarter after the Subordination Period that is deemed to be Operating Surplus pursuant to the provisions of Section 6.3 or Section 6.5 shall be distributed as follows, except as otherwise required in respect of additional Partnership Interests issued pursuant to Section 5.6(b) :

(i) First, (A) to the General Partner in accordance with its Percentage Interest and (B) to the holders of Common Units and Class A Units Pro Rata (except that the holders of Class A Units will not be entitled to receive any Hydrocarbon Available Cash), a percentage equal to 100% less the General Partner’s Percentage Interest in subclause (A), until there has been distributed in respect of each Common Unit then Outstanding an amount equal to the Minimum Quarterly Distribution for such Quarter;

(ii) Second, (A) to the General Partner in accordance with its Percentage Interest and (B) to the holders of Common Units and Class A Units, Pro Rata (except that the holders of Class A Units will not be entitled to receive any Hydrocarbon Available Cash), a percentage equal to 100% less the General Partner’s Percentage Interest in subclause (A), until there has been distributed in respect of each Common Unit then Outstanding an amount equal to the excess of the First Target Distribution over the Minimum Quarterly Distribution for such Quarter;

(iii) Third, (A) to the General Partner in accordance with its Percentage Interest, (B) 13% to the holders of the Incentive Distribution Rights, Pro Rata, and (C) to the holders of Common Units and Class A Units, Pro Rata (except that the holders of Class A Units will not be entitled to receive any Hydrocarbon Available Cash), a percentage equal to 100% less the sum of the percentages applicable to subclauses (A) and (B) of this clause (iii), until there has been distributed in respect of each Common Unit then Outstanding an amount equal to the excess of the Second Target Distribution over the First Target Distribution for such Quarter;

(iv) Fourth, (A) to the General Partner in accordance with its Percentage Interest, (B) 23% to the holders of the Incentive Distribution Rights, Pro Rata, and (C) to the holders of Common Units and Class A Units, Pro Rata (except that the holders of Class A Units will not be entitled to receive any Hydrocarbon Available Cash), a percentage equal to 100% less the sum of the percentages applicable to subclauses (A) and (B) of this clause (iv), until there has been distributed in respect of each Common Unit then Outstanding an amount equal to the excess of the Third Target Distribution over the Second Target Distribution for such Quarter; and

(v) Thereafter, (A) to the General Partner in accordance with its Percentage Interest, (B) 48% to the holders of the Incentive Distribution Rights, Pro Rata, and (C) to holders of Common Units and Class A Units, Pro Rata (except that the holders of Class A Units will not be entitled to receive any Hydrocarbon Available Cash), a percentage equal to 100% less the sum of the percentages applicable to subclauses (A) and (B) of this clause (v); provided , however , that if the Minimum Quarterly Distribution, the First Target Distribution, the Second Target Distribution and the Third Target Distribution have been reduced to zero pursuant to the second sentence of Section 6.6(a) , the distribution of Available Cash that is deemed to be Operating Surplus with respect to any Quarter will be made solely in accordance with Section 6.4(b)(v) .”

(t) Section 6.5 . Section 6.5 of the Partnership Agreement is hereby amended and restated to read as follows:

“Section 6.5 Distributions of Available Cash from Capital Surplus . Available Cash that is deemed to be Capital Surplus pursuant to the provisions of Section 6.3(a) shall be distributed, unless the provisions of Section 6.3 require otherwise, to the General Partner and the holders of Common Units, Class A Units, and Subordinated Units, if any, Pro Rata (except that the holders of Class A Units will not be entitled to receive any Hydrocarbon Available Cash), until a hypothetical holder of a Common Unit acquired on the Closing Date has received with respect to such Common Unit distributions of Available Cash that are deemed to be Capital Surplus in an aggregate amount equal to the Initial Unit Price. Available Cash that is deemed to be Capital Surplus shall then be distributed (A) to the General Partner in accordance with its Percentage Interest and (B) to the holders of Common Units, Class A Units, and Subordinated Units, if any, Pro Rata (except that the holders of Class A Units will not be entitled to receive any Hydrocarbon Available Cash), a percentage equal to 100% less the General Partner’s Percentage Interest, until there has been distributed in respect of each Common Unit then Outstanding an amount equal to the Cumulative Common Unit Arrearage. Thereafter, all Available Cash shall be distributed as if it were Operating Surplus and shall be distributed in accordance with Section 6.4 .”

(u) Article VI; Section 6.10 . Article VI is hereby amended and restated to add a new Section 6.10 to read as follows:

“Section 6.10 Special Provisions Relating to the Holders of Converted Units .

(a) A Unitholder holding a Converted Common Unit shall not be issued a Common Unit pursuant to Section 4.1 , and shall not be permitted to transfer such Converted Common Units to a Person that is not an Affiliate of the holder (subject to the other transfer restrictions set forth in this Agreement) until such time as the General Partner reasonably determines that, upon transfer, each such Converted Common Unit would have, as a substantive matter, like intrinsic economic and U.S. federal income tax characteristics to the transferee, in all material respects, to the intrinsic economic and U.S. federal income tax characteristics of an Initial Common Unit to such transferee. In connection with the condition imposed by this Section 6.10 , the General Partner shall take whatever steps are required to provide economic uniformity to the Converted Common Units in preparation for a transfer of such Converted Common Units, including the application of Section 5.5(c)(iv) and Section 6.1(d)(x) ; provided , however , that no such steps may be taken that would have a material adverse effect on the Unitholders holding Converted Common Units (for this purpose the allocations of items of income, gain, loss or deduction with respect to Common Units, Class A Units or Class B Units will be deemed not to have a material adverse effect on the Common Units).”

(b) A holder of a Converted Common Unit or a Class B Unit shall be required to provide notice to the General Partner of any transfer, disposition, or other “sale or exchange” (within the meaning of Section 708(b)(1)(B) of the Code) of any of its Converted Common Units or Class B Units within 45 days of such event, or by the last Business Day of the calendar year in which such event occurs, if shorter, providing the number of Converted Common Units or Class B Units that were transferred, disposed of or subject to the sale or exchange.”

Section 2. Adjustments to Capital Accounts . In connection with the MarkWest Merger and effective as of the date the MarkWest Merger is completed, the Capital Accounts of each Partner and the Carrying Values of each Partnership property shall be adjusted to reflect any Unrealized Gain or Unrealized Loss attributable to such Partnership property pursuant to Section 5.5(d) of the Partnership Agreement and Treasury Regulation Section 1.704-1(b)(2)(iv)(f).

Section 3. Ratification Of Partnership Agreement . Except as hereby amended, all of the terms and conditions of the Partnership Agreement shall remain in full force and effect.

Section 4. Applicable Law . This Amendment shall be construed in accordance with and governed by the laws of the State of Delaware, without regard to the principles of conflicts of laws.

Section 5. Invalidity of Provisions . If any provision of this Amendment is or becomes invalid, illegal or unenforceable in any respect, the validity, legality and enforceability of the remaining provisions contained herein shall not be affected thereby.

Section 6. Counterparts . This Amendment may be executed in counterparts, all of which together shall constitute an agreement binding on all the parties hereto, notwithstanding that all such parties are not signatories to the original or the same counterpart.

[ Signature Page Follows ]

IN WITNESS WHEREOF, the undersigned has executed this Amendment No. 1 to the First Amended and Restated Agreement of Limited Partnership of MPLX LP to be effective as of the date first written above.



	GENERAL PARTNER:

	MPLX GP LLC


	By:		/s/ Gary R. Heminger
	Name:		Gary R. Heminger
	Title:		Chairman of the Board and Chief Executive Officer

SIGNATURE PAGE TO

AMENDMENT NO. 1

FIRST AMENDED AND RESTATED

AGREEMENT OF LIMITED PARTNERSHIP OF

MPLX.

EXHIBIT A

Restrictions on Transfer of Class B Units

THE CLASS B UNITS (ALSO REFERED TO AS “THIS SECURITY”) HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED. THE CLASS B UNITS MAY NOT BE SOLD, OFFERED FOR SALE, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF A REGISTRATION STATEMENT IN EFFECT WITH RESPECT TO THE SECURITIES UNDER SUCH ACT OR AN OPINION OF COUNSEL SATISFACTORY TO MPLX LP THAT SUCH REGISTRATION IS NOT REQUIRED.

THIS SECURITY IS SUBJECT TO RESTRICTIONS ON TRANSFER SET FORTH IN SECTIONS 4.5 AND 4.8 OF AND ELSEWHERE IN THE FIRST AMENDED AND RESTATED AGREEMENT OF LIMITED PARTNERSHIP OF MPLX LP, AS AMENDED BY AMENDMENT NO. 1 THERETO, AND AS FURTHER AMENDED, SUPPLEMENTED OR RESTATED FROM TIME TO TIME (THE “PARTNERSHIP AGREEMENT”) AND THE VOTING RESTRICTIONS SET FORTH IN SECTION 5.13(D) OF THE PARTNERSHIP AGREEMENT AND IN THE DEFINITION OF THE DEFINTED TERM “OUTSTANDING” IN THE PARTNERSHIP AGREEMENT.

THE HOLDER OF THIS SECURITY ACKNOWLEDGES FOR THE BENEFIT OF MPLX LP THAT THIS SECURITY MAY NOT BE SOLD, OFFERED, RESOLD, PLEDGED OR OTHERWISE TRANSFERRED IF SUCH TRANSFER WOULD (A) VIOLATE THE THEN APPLICABLE FEDERAL OR STATE SECURITIES LAWS OR RULES AND REGULATIONS OF THE SECURITIES AND EXCHANGE COMMISSION, ANY STATE SECURITIES COMMISSION OR ANY OTHER GOVERNMENTAL AUTHORITY WITH JURISDICTION OVER SUCH TRANSFER, (B) TERMINATE THE EXISTENCE OR QUALIFICATION OF MPLX LP UNDER THE LAWS OF THE STATE OF DELAWARE, OR (C) CAUSE MPLX LP TO BE TREATED AS AN ASSOCIATION TAXABLE AS A CORPORATION OR OTHERWISE TO BE TAXED AS AN ENTITY FOR FEDERAL INCOME TAX PURPOSES (TO THE EXTENT NOT ALREADY SO TREATED OR TAXED). MPLX GP LLC, THE GENERAL PARTNER OF MPLX LP, MAY IMPOSE ADDITIONAL RESTRICTIONS ON THE TRANSFER OF THIS SECURITY IF IT RECEIVES AN OPINION OF COUNSEL THAT SUCH RESTRICTIONS ARE NECESSARY TO AVOID A SIGNIFICANT RISK OF MPLX LP BECOMING TAXABLE AS A CORPORATION OR OTHERWISE BECOMING TAXABLE AS AN ENTITY FOR FEDERAL INCOME TAX PURPOSES.

A-1

EXHIBIT B

DISCOUNTED CONVERSION NUMBERS



Series of Class B Units	9/30/2015 through 12/30/2015	12/31/2015 through 3/30/2016	3/31/2016 through 6/29/2016	6/30/2016 through 9/29/2016	9/30/2016 through 12/30/2016	12/31/2016 through 3/30/2017	3/31/2017 through 6/29/2017	6/30/2017 and thereafter
Class B-1 Units	0.9571802	0.9714535	0.9857267	1	1	1	1	1
Class B-2 Units	0.8987070	0.9131775	0.9276479	0.9421183	0.9565887	0.9710592	0.9855296	1

B-2

LOAN AGREEMENT

between

MPLX LP

As the Borrower

and

MPC INVESTMENT LLC

As the Lender

Dated as of December 4, 2015

LOAN AGREEMENT

THIS LOAN AGREEMENT (as amended, restated, supplemented or otherwise modified from time to time, this “ Loan Agreement ”) is entered into as of December 4, 2015 (the “ Effective Date ”), by and between MPLX LP, a Delaware limited partnership (the “ Borrower ”), and MPC Investment LLC, a Delaware limited liability company (the “ Lender ”). The Borrower and the Lender may be singularly referred to as a “ Party ” and collectively referred to as the “ Parties .”

WITNESS:

WHEREAS , as of the Effective Date, the Lender is the sole member of MPLX GP LLC, a Delaware limited liability company and general partner of the Borrower (the “ General Partner ”), and, as such, the General Partner stands to benefit from the extension of credit to the Borrower;

WHEREAS , to provide credit support to the Borrower, the Lender has agreed to enter into this Loan Agreement and to provide loans to the Borrower from time-to-time on a revolving basis to fund the Borrower’s financing needs with respect to capital expenditures, working capital, acquisitions and general partnership purposes.

NOW, THEREFORE , in consideration of the promises and mutual representations, warranties and covenants in this Loan Agreement, the Parties hereby agree as follows:

ARTICLE 1

DEFINITIONS

1.1 Capitalized terms used in this Loan Agreement have the meanings and are subject to the rules of construction set forth in Appendix A .

ARTICLE 2

LOAN

2.1 Loans . Subject to the terms provided for in this Loan Agreement, the Lender shall from time-to-time on or after the Effective Date make loans to the Borrower on a revolving basis (each, a “ Loan ” and collectively, the “ Loans ”), as requested by the Borrower and agreed to by the Lender (in the Lender’s sole discretion), in amounts that do not result in the aggregate principal amount of all Loans outstanding exceeding Five Hundred Million U.S. Dollars ($500,000,000) at any one time.

2.2 Maturity . The entire unpaid principal amount of the Loans (together with all accrued and unpaid interest and other amounts, if any, payable hereunder) shall mature and become due and payable on the fifth anniversary of the Effective Date (such date, the “ Maturity Date ”); provided , however , that the Lender may demand payment of all or any portion of the outstanding principal amount of the Loan (together with all accrued and unpaid interest and other amounts, if any, payable hereunder) at any time prior to the Maturity Date by providing written demand to the Borrower. The Borrower shall pay any amounts so demanded to be paid by the Lender not later

than three business days following the receipt by the Borrower of the written demand. Notwithstanding the foregoing, the Lender may not make any partial demand for payment in an amount less than Two Million U.S. Dollars ($2,000,000).

2.3 Optional Prepayment . The Borrower may, at any time prior to the Maturity Date and without penalty, pay all or any portion of the unpaid principal amount of the Loans, together with all accrued and unpaid interest and other amounts, if any, payable hereunder; provided , however , that the Borrower may not make any partial prepayment in an amount less than Two Million U.S. Dollars ($2,000,000).

2.4 Promissory Note . The Loan will be evidenced by a single Non-negotiable Promissory Note, dated as of the Effective Date (the “ Promissory Note ”), to be executed by the Borrower in a form acceptable to the Lender concurrently with the execution and delivery of this Loan Agreement. The Promissory Note shall be delivered to and made payable to the Lender. The Lender shall record, on a schedule to the Promissory Note, (i) the amount and date of each Loan made by the Lender to the Borrower pursuant to Section 2.1 , (ii) the amount of interest that accrues on the outstanding principal amount of the Loans during each Interest Period, (iii) the date and amount of each payment of interest or principal made by the Borrower and (iv) the balance of the principal amount of the Loan, including unpaid and accrued interest, if any, as of the end of each Interest Period; provided that the failure of the Lender to record such information or any error therein shall not in any manner affect the obligation of the Borrower to repay the Loans in accordance with the terms of this Loan Agreement..

2.5 Payments of Principal and Interest . The Borrower shall make all payments of principal and interest or other amounts, if any, that are required to be made under this Loan Agreement by wire or interbank transfer of immediately available funds to an account or accounts designated by the Lender. Any payments received by the Lender from the Borrower shall first be applied to any unpaid interest that is then due and payable with the remainder of such payments to be applied to the unpaid principal amount of the Loan.

ARTICLE 3

INTEREST

3.1 Interest . Interest shall accrue on the unpaid principal amount of the Loan at a rate equal to the sum of (i) the one (1) month term, London Interbank Offered Rate (LIBOR Rate) for dollar deposits, as published by Bloomberg or if not so published, then by the Financial Times of London on the first Business Day of such Interest Period, plus (ii) a premium of one hundred fifty basis points (1.50%). Interest shall be calculated for each Interest Period on the daily principal balance of the Loan outstanding during such Interest Period on the basis of a year of 360 days for the actual number of days elapsed.

3.2. Interest Payments . The Borrower shall pay interest in arrears on the last day of each Interest Period; provided , however , that (i) any interest accrued pursuant to Section 3.3 shall be payable on demand and (ii) in the event of a demand by the Lender for repayment of the outstanding principal amount of the Loan or prepayment of the entire principal amount of the Loan

in accordance with Article 2 , accrued and unpaid interest on the Loan shall be payable on the date of such repayment or prepayment. For the avoidance of doubt, in the event of any demand for repayment or prepayment of less than the entire outstanding principal amount of the Loan in accordance with Article 2 , unpaid interest that has accrued on the portion of the principal amount of the Loan so repaid or prepaid, as the case may be, shall be payable on the last day of the applicable Interest Period in accordance with this Section 3.2 .

3.3 Delinquent Payments . Notwithstanding the foregoing, if any principal payment, interest or other amount, if any, required to be paid on any Loan is not paid when due and payable hereunder, such overdue amount shall bear interest, after as well as before judgment, on the basis of a year of 360 days for the actual number of days elapsed through the date of payment, at a rate per annum equal to two percentage points (2.00%) plus the interest rate otherwise payable on the principal balance of such Loan as provided in Section 3.1 .

ARTICLE 4

WARRANTIES

Each Party hereby represents and warrants to the other, as of the Effective Date, that:

4.1 Organization; Powers . Such Party (a) is duly organized, validly existing and in good standing under the laws of the jurisdiction of its organization, (b) has all the requisite power and authority to carry on its business as now conducted and (c) except where the failure to be so qualified or in good standing would not reasonably be expected to have a Material Adverse Effect, is qualified to do business in, and is in good standing in, every jurisdiction where such qualification is required.

4.2 Authorization; Enforceability . The execution, delivery and performance by such Party of this Loan Agreement and the other Loan Documents are within such Party’s limited liability company or limited partnership powers, as applicable, and have been duly authorized by all necessary limited liability company or limited partnership action, as applicable. This Loan Agreement has been, and each other Loan Document, when delivered hereunder will have been, duly executed and delivered by each Party that is a party thereto. This Loan Agreement constitutes, and each other Loan Document when so executed and delivered will constitute, a legal, valid and binding obligation of each Party that is a party thereto, enforceable against such Party in accordance with its terms, subject to applicable bankruptcy, insolvency, reorganization, moratorium or other laws affecting creditors’ rights generally and subject to general principles of equity, regardless of whether considered in a proceeding in equity or at law.

4.3 Governmental Approvals; No Conflicts . The execution, delivery and performance by each Party of this Loan Agreement and each other Loan Document to which it is a party (a) do not require any consent or approval of, registration or filing with, or any other action by, any Governmental Authority, except such as have been obtained or made and are in full force and effect, (b) will not violate in any material respect any law or regulation or any order of any Governmental Authority, in each case, applicable to or binding upon such Party or any of its property, (c) will not violate or result in a default under any indenture, agreement or other instrument binding upon such Party, or by which any property or asset of such Party is bound,

except to the extent that a Material Adverse Effect would not reasonably be expected to result therefrom and (e) will not violate the organizational documents of such Party.

ARTICLE 5

COVENANTS

From and after the Effective Date and until the principal amount and interest on the Loan and other amounts, if any, payable hereunder have been paid in full (other than indemnities and other contingent obligations not then due and payable and as to which no claim has been made), the Borrower covenants and agrees with the Lender that:

5.1 Existence; Conduct of Business . The Borrower will do or cause to be done all things necessary to preserve, renew and keep in full force and effect its legal existence and the rights, licenses, permits, privileges and franchises material to the conduct of its business except to the extent that the failure to maintain and preserve the same would not reasonably be expected to result in a Borrower Material Adverse Effect.

5.2 Payment of Taxes and other Obligations . The Borrower will pay its Tax liabilities and other governmental obligations which, if unpaid, would reasonably be expected to result in a Lien upon any property of the Borrower before the same shall become delinquent or in default, except to the extent that (a) the validity or amount thereof is being contested in good faith by appropriate proceedings or (b) the failure to make such payment would not reasonably be expected to result in a Borrower Material Adverse Effect.

5.3 Maintenance of Properties; Insurance . The Borrower will (a) maintain all property material to the conduct of its business in good working order and condition, ordinary wear and tear excepted, and (b) maintain, with financially sound and reputable insurance companies, insurance in such amounts and against such risks as are customarily maintained by companies engaged in the same or similar businesses operating in the same or similar locations and of similar size (including, without limitation, by the maintenance of adequate self-insurance reserves to the extent customary among such companies).

5.4 Books and Records; Inspection Rights . The Borrower will keep proper books of record and account in which complete and accurate entries, in all material respects, are made of its financial and business transactions to the extent required by GAAP and applicable law. The Borrower will permit any representatives designated by the Lender, at the Lender’s expense (unless an Event of Default has occurred and is continuing, in which case it shall be at the Borrower’s sole expense) and upon reasonable prior notice and subject to any applicable restrictions or limitations on access to any facility or information that is classified or restricted by contract or by law, regulation or governmental guidelines, to visit and inspect the Borrower’s properties, to examine and make extracts from the Borrower’s books and records, and to discuss the Borrower’s affairs, finances and condition with the Borrower’s officers and independent accountants.

5.5 Compliance with Laws . The Borrower shall comply with all laws, rules, regulations and orders of any Governmental Authority applicable to it or its property, except where the failure to do so would not reasonably be expected to result in a Borrower Material Adverse Effect.

5.6 Compliance with Revolving Credit Agreement . The Borrower will comply in all material respects with the covenants, terms and conditions to which it is subject under the Credit Facility, including, without limitation, the covenants restricting the Borrower’s ability to incur indebtedness or create or allow there to be created liens on the Borrower’s properties and assets.

5.7 Use of Proceeds . The Borrower shall use the proceeds from the Loans for working capital and general partnership purposes.

ARTICLE 6

EVENTS OF DEFAULT

If any of the following events (“ Events of Default ”) shall occur on or after the Effective Date and until the principal and interest on the Loan and other amounts, if any, payable hereunder have been paid in full (other than indemnities and other contingent obligations not then due and payable and as to which no claim has been made):

6.1 the Borrower fails to make any payment on the principal of the Loan when and as the same shall become due and payable hereunder;

6.2 the Borrower fails to make any interest payment on the Loan or fails to make any other payment, if any, required to be under this Loan Agreement (other than an amount referred to in Section 6.1 ), when and as the same shall become due and payable, and such failure shall continue unremedied for a period of 10 days after the Borrower receives written demand for payment from the Lender;

6.3 any representation or warranty made by the Borrower in this Loan Agreement or any other Loan Document shall prove to have been inaccurate when made without giving effect to any materiality or Material Adverse Effect qualifier contained therein and such inaccuracy is reasonably likely to result in a Borrower Material Adverse Effect;

6.4 the Borrower fails to observe or perform any covenant or agreement contained in this Loan Agreement or other Loan Document, and such failure shall continue unremedied for a period of 30 days after receipt of notice thereof from the Lender to the Borrower;

6.5 an involuntary proceeding is commenced, or an involuntary petition is filed, in any court of competent jurisdiction seeking (i) liquidation, reorganization or other relief in respect of the Borrower or its debts, or of a substantial part of its assets, under any Federal, state or foreign bankruptcy, insolvency, receivership or similar law now or hereafter in effect or (ii) the appointment of a receiver, trustee, custodian, conservator or similar official for the Borrower or for a substantial part of its assets, and, in any such case, such proceeding or petition shall continue undismissed for 60 days or an order or decree approving or ordering any of the foregoing shall be entered by such court;

6.6 the Borrower shall (i) voluntarily commence any proceeding or file any petition seeking liquidation, reorganization or other relief under any Federal, state or foreign bankruptcy, insolvency, receivership or similar law now or hereafter in effect, (ii) consent to the institution of, or fail to contest in a timely and appropriate manner, any proceeding or petition described in Section 6.5 , (iii) apply for or consent to the appointment of a receiver, trustee, custodian, conservator or similar official for the Borrower or for a substantial portion of its assets, (iv) file an answer admitting the material

allegations of a petition filed against it in any such proceeding, (v) make a general assignment for the benefit of creditors or (vi) take any corporate action for the purpose of effecting any of the foregoing;

6.7 the Borrower shall become unable, admit in writing its inability or fail generally to pay its debts as they become due; or

6.8 any event occurs that results in the suspension or termination of the Lender’s commitments to the Borrower under the Credit Facility.

then, and in every such event the Lender may, upon written notice to the Borrower, declare the principal amount of each Loan then outstanding, together with all accrued and unpaid interest thereon, and other amounts, if any, required to be paid hereunder due and payable immediately, without presentment, demand, protest or other notice of any kind, all of which are hereby waived by the Borrower.

ARTICLE 7

MISCELLANEOUS

7.1 Notices . (a) All notices and other communications required or permitted to be provided under this Loan Agreement or any other Loan Document shall be in writing and shall be sent via electronic mail and confirmed by hard copy delivery by hand or overnight courier service, mailed by certified or registered mail, as follows:

(i) if to the Borrower, to:

200 E. Hardin Street
Findlay, Ohio 45840
Attention: Thomas Kaczynski, Vice President of Finance and Treasurer
tkaczynski@marathonpetroleum.com; or

(ii) if to the Lender, to:

539 S. Main St.
Findlay, Ohio 45840
Attention: Timothy T. Griffith, Senior Vice President and Chief Financial Officer
ttgriffith@marathonpetroleum.com.

(b) Any Party may change its address or electronic mail address for notices and other communications hereunder by providing notice to the other Party hereto in accordance with this Section 7.1 . Notices sent by hand or overnight courier service, or mailed by certified or registered mail, shall be deemed to have been given when received. Notices sent by electronic email shall be deemed to have been given when sent (except that, if not given during normal business hours for the recipient, shall be deemed to have been given at the opening of business on the next business day for the recipient).

7.2 Waivers; Amendments . No failure or delay by the Lender in exercising any right or power hereunder shall operate as a waiver thereof, nor shall any single or partial exercise of any such right or power, or any abandonment or discontinuance of steps to enforce such a right or power, preclude any other or further exercise thereof or the exercise of any other right or power. The rights and remedies of the Lender hereunder are cumulative and are not exclusive of any rights or remedies that they would otherwise have. No waiver or amendment or other modification of any provision of this Loan Agreement will be effective except as agreed to in writing by the Borrower and the Lender.

7.3 Expenses . The Borrower shall pay all reasonable and documented out of pocket expenses incurred by the Lender, including the reasonable attorney fees, in the preparation and administration of this Loan Agreement and any amendments, modifications or waivers of the provisions hereof, or in connection with the enforcement or protection of the Lender’s rights hereunder.

7.4 Indemnity . The Borrower shall indemnify the Lender against, and hold the Lender harmless from, any and all losses, claims, damages, settlements and liabilities incurred by, asserted against or otherwise involving the Lender arising out of, in connection with, or as a result of (i) the execution or delivery of this Loan Agreement or any other Loan Document, the performance by the Parties hereto of their respective obligations under this Loan Agreement or other Loan Document or the consummation of the transactions contemplated hereby or the enforcement of the Lender’s rights under this Loan Agreement or other Loan Document, (ii) the Loans or the use of the proceeds therefrom or (iii) any actual or prospective claim, suit, cause of action, litigation, investigation or proceeding relating to any of the foregoing (a “ Covered Proceeding ”), whether based on contract, tort or any other theory and regardless of whether the Lender is a party thereto and regardless of whether brought by a third party or by the Borrower; provided ; however , that the foregoing indemnity shall not be available to the extent that such losses, claims, damages, settlements, liabilities or related expenses are found by a final, non-appealable judgment of a court of competent jurisdiction to arise out of or in connection with the willful misconduct or gross negligence of the Lender or the material breach by the Lender of this Loan Agreement or other Loan Document. The Borrower shall promptly upon demand reimburse the Lender for any costs and expenses (including reasonable attorney fees) incurred in the investigation, participation or defense of any Covered Proceeding, provided that the Lender undertakes in writing to repay any such costs or expenses so reimbursed upon a final, non-appealable judgment of a court of competent jurisdiction finding that the Lender is not entitled to indemnification with respect to such Covered Proceeding.

7.5 Successors and Assigns . The provisions of this Loan Agreement shall be binding upon and inure to the benefit of the parties hereto and their respective successors and assigns, provided , however , that the Borrower may not assign or otherwise transfer any of its rights or obligations hereunder without the prior written consent of the Lender (and any attempted assignment or transfer by the Borrower without such consent shall be null and void).

7.6 No Third Party Beneficiaries . Nothing in this Loan Agreement, expressed or implied, shall be construed to confer upon any person or entity other than the Parties and their respective successors and permitted assigns any legal or equitable right, remedy or claim under or by reason of this Loan Agreement.

7.7 Survival . All covenants, agreements, representations and warranties made by the Borrower herein or in any other Loan Document shall be considered to have been relied upon by the Lender and shall survive the execution and delivery of this Loan Agreement and the making of the Loan, regardless of any investigation made by the Lender or on its behalf and notwithstanding that the Lender may have had notice or knowledge of any incorrect representation or warranty at the time of making the Loan, and shall continue in full force and effect until the principal balance of the Loan, any accrued interest on the Loan and other amounts, if any, payable hereunder are paid in full, at which time all covenants, agreements, representations and warranties will automatically, without any further action by the Parties, terminate and be of no further force and effect except as with respect to any claims for indemnification arising prior to the effective date of such termination.

7.8 Counterparts; Integration . This Loan Agreement and the other Loan Documents may be executed in counterparts, each of which shall constitute an original, but all of which when taken together shall constitute a single contract. This Loan Agreement and the other Loan Documents constitute the entire agreement among the Parties relating to the subject matter hereof and supersede any and all previous agreements and understandings, oral or written, relating to the subject matter hereof.

7.9 Severability . Any provision of this Loan Agreement held to be invalid, illegal or unenforceable in any jurisdiction shall, as to such jurisdiction, be ineffective to the extent of such invalidity, illegality or unenforceability without affecting the validity, legality and enforceability of the remaining provisions hereof, and the invalidity of a particular provision in a particular jurisdiction shall not invalidate such provision in any other jurisdiction.

7.10 Right of Setoff . If an Event of Default shall have occurred and be continuing, the Lender is hereby authorized at any time and from time to time, to the fullest extent permitted by applicable law, to set off and apply any or all of the existing payment obligations of the Lender or any of its Affiliates to the Borrower against any or all of the obligations of the Borrower which are then due and payable under this Loan Agreement. The Lender agrees to promptly notify the Borrower after any such setoff; provided , however , that the failure to give such notice shall not affect the validity of such setoff and application.

7.11 Governing Law; Jurisdiction; Consent to Service of Process . (a) This Loan Agreement and the other Loan Documents shall be construed in accordance with and governed by the law of the State of Ohio.

(b) Each party hereto hereby irrevocably and unconditionally submits, for itself and its property, to the exclusive personal jurisdiction of United States District Court located within the State of Ohio, and any appellate court from any thereof, or if such court is not permitted to adjudicated such matter under federal law, to any Ohio state court of first impression, in any action or proceeding or the recognition or enforcement of any judgment, arising out of or relating to this Loan Agreement, any other Loan Document or the transactions contemplated hereby or thereby, and each party hereto hereby irrevocably and unconditionally agrees that all claims in respect of any such action or proceeding may be heard and determined solely in such courts. Each party hereto agrees that a final judgment in any such action or proceeding shall be conclusive and may be enforced in other jurisdictions by suit on the judgment or in any other manner provided by law.

(c) Each party hereto hereby irrevocably and unconditionally waives, to the fullest extent it may legally and effectively do so, any objection which it may now or hereafter have to the laying of venue of any suit, action or proceeding arising out of or relating to this Loan Agreement, any other Loan Document or the transactions contemplated hereby or thereby in any court referred to in paragraph (b) of this Section 7.11 . Each party hereto hereby irrevocably waives, to the fullest extent permitted by law, the defense of an inconvenient forum to the maintenance of such action or proceeding in any such court.

(d) Each party hereto irrevocably consents to service of process in the manner provided for notices in Section 7.1 above. Nothing in this Loan Agreement will affect the right of any Party to this Loan Agreement to serve process in any other manner permitted by law.

7.12 WAIVER OF JURY TRIAL . EACH PARTY HERETO HEREBY IRREVOCABLY WAIVES, TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, ANY RIGHT IT MAY HAVE TO A TRIAL BY JURY IN ANY LEGAL PROCEEDING DIRECTLY OR INDIRECTLY ARISING OUT OF OR RELATING TO THIS LOAN AGREEMENT OR ANY OTHER LOAN DOCUMENT OR THE TRANSACTIONS CONTEMPLATED HEREBY OR THEREBY (WHETHER BASED ON CONTRACT, TORT OR ANY OTHER THEORY). EACH PARTY HERETO (A) CERTIFIES THAT NO REPRESENTATIVE, AGENT OR ATTORNEY OF ANY OTHER PARTY HAS REPRESENTED, EXPRESSLY OR OTHERWISE, THAT SUCH OTHER PARTY WOULD NOT, IN THE EVENT OF LITIGATION, SEEK TO ENFORCE THE FOREGOING WAIVER AND (B) ACKNOWLEDGES THAT IT AND THE OTHER PARTIES HERETO HAVE BEEN INDUCED TO ENTER INTO THIS LOAN AGREEMENT AND THE OTHER LOAN DOCUMENTS BY, AMONG OTHER THINGS, THE MUTUAL WAIVERS AND CERTIFICATIONS IN THIS SECTION 7.12 .

7.13 Headings . Article and Section headings used herein are for convenience of reference only, are not part of this Loan Agreement and shall not affect the construction of, or be taken into consideration in interpreting, this Loan Agreement.

7.14 Interest Rate Limitation . Notwithstanding anything herein to the contrary, if at any time the interest rate applicable to the Loan, together with all fees, charges and other amounts, if any, which are treated as interest on the Loan under applicable law shall exceed the maximum lawful rate (the “ Maximum Rate ”) which may be contracted for, charged, taken, received or reserved by the Lender holding the Loan in accordance with applicable law, the rate of interest payable in respect of the Loan hereunder, together with all fees, charges and other amounts payable in respect thereof, shall be limited to the Maximum Rate.

IN WITNESS WHEREOF , each of the Parties has executed this Loan Agreement as of the Effective Date.



	MPC INVESTMENT LLC

	By:		/s/ Timothy T. Griffith
			Timothy T. Griffith
			Senior Vice President and Chief Financial Officer


	MPLX LP

	By:		MPLX GP LLC, its General Partner

	By:		/s/ Thomas Kaczynski
			Thomas Kaczynski
			Vice President of Finance and Treasurer

APPENDIX A

DEFINITION OF TERMS

Introductory Note--Construction . Whenever the context requires, the gender of all words used in this Loan Agreement includes the masculine, feminine and neuter and terms defined in the singular have the corresponding meanings in the plural, and vice versa. Except as this Loan Agreement otherwise specifies, all references herein to any law, are references to that law (and any rules and regulations promulgated thereunder), as the same may have been amended. The word “includes” or “including” means “including, but not limited to,” unless the context otherwise requires. The words “shall” and “will” are used interchangeably and have the same meaning. The words “this Loan Agreement,” “hereof,” “hereby,” “herein,” “hereunder” and similar terms in this Loan Agreement refer to the relevant agreement as a whole and not any particular Section or Article in which such words appear. If a word or phrase is defined, its other grammatical forms have a corresponding meaning. Whenever this Loan Agreement refers to a number of days, such number shall refer to calendar days unless business days are specified. Time periods within or following which any payment is to be made or an act is to be done shall be calculated by excluding the day on which the time period commences and including the day on which the time period ends. Unless specifically provided for in this Loan Agreement, the term “or” shall not be deemed to be exclusive. References to a person are also to its successors and/or permitted assigns, if any. All exhibits and annexes attached to this Loan Agreement constitute a part of this Loan Agreement and are incorporated herein for all purposes. All references to currency in this Loan Agreement shall be to, and all payments required under this Loan Agreement shall be paid in, lawful currency of the United States.

Definitions .

“ Borrower ” has the meaning set forth in the preamble.

“ Borrower Material Adverse Effect ” means a material adverse effect on (a) the business, operations, property or financial condition of the Borrower, (b) the ability of the Borrower to perform its obligations under the Loan Documents or (c) the rights and remedies of the Lender under the Loan Documents.

“ Covered Proceeding ” has the meaning set forth in Section 7.4 .

“ Credit Facility ” means that certain Credit Agreement, dated as of November 20, 2014 and amended by that certain Amendment Agreement, dated as of October 27, 2015, by and among the Borrower, as borrower, Wells Fargo Bank, National Association, as administrative agent, and the various financial banking institutions that are lending parties thereto and as may be further amended, amended and restated, supplemented, modified, replaced or superseded.

“ Effective Date ” has the meaning set forth in the preamble.

“ Events of Default ” has the meaning set forth in Article 6.

“ Governmental Authority ” means any federal, state, local, foreign, multi-national, supra-national, national, regional or other governmental agency, authority, administrative agency, regulatory body, commission, board, bureau, agency, officer, official, instrumentality, court or arbitral tribunal having governmental or quasi-governmental powers or any other instrumentality or political subdivision thereof; provided , however , that such term shall not include any entity or organization that is engaged in industrial or commercial operations and is wholly or partly owned by any government, to the extent that such entity or organization is acting in a commercial capacity.

“ Interest Period ” means each successive calendar month during which any principal amount or interest on the Loans is outstanding.

“ Lender ” has the meaning set forth in the preamble.

“ Lender Material Adverse Effect ” means a material adverse effect on (a) the business, operations, property or financial condition of the Lender or (b) the ability of the Lender to perform its obligations under the Loan Documents.

“ Loan ” has the meaning set forth in Section 2.1 .

“ Loan Agreement ” has the meaning set forth in the preamble.

“ Loan Documents ” means collectively, the Loan Agreement, the Promissory Note and each other ancillary agreement, certificate, instrument or other document required or contemplated to be executed in connection with the Loan Agreement or any Loan.

“ Material Adverse Effect ” means a Borrower Material Adverse Effect or a Lender Material Adverse Effect, as applicable.

“ Maturity Date ” has the meaning set forth in Section 2.2 .

“ Maximum Rate ” has the meaning set forth in Section 7.14 .

“ Party ” has the meaning set forth in the preamble.

“ Promissory Note ” has the meaning set forth in Section 2.4

“ Tax ” means (i) any and all federal, state, provincial, county, local or foreign taxes or levies of any kind and any and all other like assessments, customs, duties, imposts, charges or fees, including income, gross receipts, ad valorem, value added, excise, real property, personal property, escheat, asset, sales, use, franchise, license, payroll, transaction, capital, capital gains, net worth, withholding, estimated, social security, utility, workers’ compensation, severance, disability, wage, employment, production, unemployment compensation, occupation, premium, windfall profits, transfer, gains, alternative or add-on minimum, stamp, documentary, recapture, business license, business organization, environmental, profits, lease, or other taxes or other charges imposed by or

on behalf or payable to any Governmental Authority, together with any interest, fines, penalties, assessments, or additions resulting from, attributable to, or incurred in connection with any of the foregoing (whether or not disputed) and (ii) any transferee or other secondary or non-primary liability or other obligations with respect to any item in clause (i) above, whether such liability or obligation arises by assumption, operation of law, contract, indemnity, guarantee, as a successor or otherwise).

NON-NEGOTIABLE PROMISSORY NOTE

Findlay, Ohio

December 4, 2015

FOR VALUE RECEIVED, the undersigned, MPLX LP , a Delaware limited partnership (the “ Borrower ”), hereby promises to pay to MPC Investment LLC, a Delaware limited liability company (the “ Lender ”) an amount equal to the aggregate principal amount of the Loan as set forth on Schedule 1 attached hereto and determined in accordance with that certain Loan Agreement, dated as of December 4, 2015, by and between the Borrower and the Lender (the “ Loan Agreement ”), payable at such times, and in such amounts, as are specified in the Loan Agreement. Capitalized terms used and not defined herein have the meanings given to them in the Loan Agreement.

The Borrower promises to pay interest on the unpaid principal amount of the Loan from the Effective Date until such principal amount is paid in full, at such interest rates, and payable at such times, as are specified in the Loan Agreement.

Both principal and interest payable to the Lender under this Non-negotiable Promissory Note are to be paid in U.S. Dollars to an account or accounts specified by the Lender via wire or interbank transfer of immediately available funds.

This Non-negotiable Promissory Note is issued pursuant to, governed by and is entitled to the benefits of, the Loan Agreement.

The Loan Agreement, among other things, contains provisions providing for the acceleration of the Maturity Date of the unpaid principal amount of the Loans upon demand by the Lender or upon the occurrence of certain stated events and allowing for prepayments on account of the Borrower prior to the Maturity Date upon the terms and conditions specified in the Loan Agreement.

Demand, diligence, presentment, protest and notice of non-payment are hereby waived by the Borrower.

THIS NON-NEGOTIABLE PROMISSORY NOTE SHALL BE GOVERNED BY, AND CONSTRUED AND INTERPRETED IN ACCORDANCE WITH, THE LAW OF THE STATE OF OHIO.

IN WITNESS WHEREOF, the Borrower has caused this Non-negotiable Promissory Note to be executed and delivered by its duly authorized officer as of the day and year set forth above.



	MPLX LP

	By:		MPLX GP LLC, its General Partner

	By:		/s/ Thomas Kaczynski
	Name:		Thomas Kaczynski
	Title:		Vice President of Finance and Treasurer

Schedule 1

Principal Amount of the Loan



Date	Loan	Interest Accrued	Interest Paid	Principal Paid	Ending Principal Balance

RETENTION AGREEMENT

TH IS RE TENTI ON A GREEMEN T ("Retention Agreement"), is made and entered into on S e ptember 14, 2015, by and between Marathon Petroleum Company LP (the "Company " ) , and Nancy K. Buese ("Execu tive") t o be eff ecti v e as of the closing of the Merger.

RECITALS

WHER EAS , Executive and MarkWest Hydrocarbon, Inc., a subsidiary of MarkWest Energy Partners, L.P ., a r e parties to that certain Employment Agreement dated, Se p t e mber 5, 2007, a copy of which is attached hereto as Ex h i b i t A (" Prior Agreement"), under which Executive is entit led t o , a mon g oth er things, lump sum cash severance benefits as described in Section 5(a) of the Prior Agreement ("Severance Benefits") upon c ert a in terminations of employment, including a quali fying volun t ary t er minat i on by Executive under Section 5(e)(ii)(E) of the Prior Agreement within one year of a "C hange of Control" (as such term is defined in the Prior Agreement);

WHE REAS , on July 11, 2015, MarkWest Energy Partners, L.P. entered into an Agreement and Plan of Merger among MPLX LP, MPLX GP LLC, Marathon Petroleum Corporation , and Sapphire Hold c o LLC, a s a mended (the "Merger Agreement"), pursuant to w hich S ap phire H o ldco LLC will be merged with and into MarkWest Energy Partners, L.P . , with MarkWest Energy Partners, L.P. continuing as the surviving e n tit y ( t he " Merger");

WHE REAS , if consummated, the Merger would constitute a Change of Control under the Prior Agreement and, following the Closing, Executive would become an employee of the Company or one of its wholly owned subsidiaries ( rat her than an employee of MarkWest Hydrocarbon, Inc.), but Executive would continue to provide services to MarkWest Energy Partners, L.P. and certain related entities; and

WHE REAS , Executive and the Company now desire, contingent on the closing of the Merger, to enter into this Retention Agreement as of the date hereof, which Retention Agreement shall become effective contingent upon the closing of th e Merger ("Closing").

NOW, THEREFORE , contingent on the Closing, in consideration of t he mutual promises contained her e i n , and fo r o th er goo d an d v aluable consideration, the receipt and sufficiency of which a r e h ere by acknowledged, Executive and the Company (the "Parties"), intending to be legally bound, hereby agree as provided herein.

T e rmination of Prior Agreement. Executive and the Company mutually agree that, notwithstanding anything in the Prior Agreement to the contrary, except as provided in this Re t ention Agreement, the Prior Agreement (and the Term (as defined in the Prior Agreement ) of the Prior Agreement) shall terminate, without penalty, on th e date on w hich th e C losing ac t u a lly occurs ( t he " Closing Date") and, from and after the Closing Da t e, neither Executive nor the Company shall have any rights or obligations under t he Prior Agreement. For the sake of clarity, as of the Closing

Date, Executive shall not have any rights or entitlement to the Severance Benefits under the Prior Agreement. Executive shall, however, be entitled to the accelerated vesting of equity awards under any MarkWest Hydrocarbon, Inc. or Mark Wes t Energy Partners, L.P . equity p lan or under Section 3(c)(ii) of the Employment Agreement that will come due as a consequence of the Change of Control resulting from the consummation of the Merger.

Position and Duties. Commencing on the Closing Date, Executive shall serve as Executive Vice President and Chief Financial Officer at MPLX GP LLC. During Executive's continued employment with the Company or its Affiliates, Executive shall perform the duties assigned to Executive by t he Company's Chief Executive Officer or its designee from time to time, and E xecut i ve shall devot e s ub stan tially all of Executive's full business time, attention and effort to the affairs of the Company and its Affiliates an d s h a ll use reasonable best efforts to promote the interests of the Company and its Affiliates. As used in this Retention Agreement, "Affiliate" means, with respect to any entity, any other entity that directly or indir ect ly controls, is controlled by, or is under common contro l with suc h first entity, and specifically includes any entity that is under common control with Marathon Petroleum Corporation .


3.	Compensation and Be n e fits.


a.	Salary. For services commencing on the Closing Date, the Company shall pay, or shall cause Executive's then-current employer to pay, Executive in accordance wit h its normal payroll practices an annual salary at a rate of $450,000 per year. Executive will be eligible for a market-based pay increase in April of 2016 and each succeeding April thereafter in accordance with Company practices.

Retention Bonus. As soon as adminis trat iv ely feasib le after the Closing Date, but in no eve nt later than the 1 ^st day of the month coincident with or next following the Closin g Date, Executive shall be granted an award cumulatively valued in the amount of $4,271,400 as of the actual grant date. The award, as described in the prior sentence, shal l be divided into separate grants, as set out below.

i. Retention Award . Executive sha ll be granted a retention award in the amount of $1,808,900 (the "Retention Award"). The Retention Award shall be paid part in cash (the "Cash Portion") and part in phantom partnership units of MPLX LP (the "Equity Portion") .


1.	The Cash Portion of the Retention Award sha ll be equal to the sum of (i) the employee portion of the Federal Insurance Contribution Act ("F ICA") taxes that are due and required to be withheld upon grant of the Retention Award ("FICA Amoun t") p lus , (ii) all income tax withholdings due as a result of the taxable nature of the payment of the

FICA Amount (it being understood that the amounts in t his subsection (ii) must be cal culated iterati vel y to account for the circular nature of the income tax withh o lding obligations related to the payment of the FICA Amount and the related income tax withholdings). The Cash Portion shall be timely remitted directly to the relevant taxing authorities.

The Equity Portion shal l equal the excess of (i) the Retention Award, over (ii) the Cash Portion . The Equity Portion shall consist of phantom partnership units of MPLX LP value d as of the actual grant date. As will be provided in the ap plicable award agreement, th e phantom partnership units and accrued DERS/distributions shall vest and become payable upon Executive's separation from service (within the meaning of Section 409A of the Internal Revenue Code of 1986, as ame nded (the “ Code")) from the ap plicable Code Section 409A "service r ecipient" w ith respect to the Retention Award (as defined in Treasury Regulation 1.409A l(h)(3) for any reason and at any time , except if Executive's se paration from service is due to t he termination of his employment for Cause (as defined in Section 4(b) of the Prior Agreement, except that the terms "Board," "Company," and "Partnership," as u sed in Section 4 (b) of the Prior Agreement shall mean the Company, as herein defined, or the Executive's employer, a s the case may be). If Executive's "separation from service" is due to the termination of his employment for Cause, the Retention Award and the phantom partnership units under this Paragraph 3.b.i. shall be forfeited in their entirety. The phantom partnership units contemplated under this Paragraph 3.b.i. shal l be subject to the terms and conditions of the MPLX LP 2012 Incentive Compensation Plan, attached hereto as Exhibit B, and the applicable award agreement, which shall be similar in form to the MPLX LP 2012 Incentive Compensation Plan Phantom Unit Award Agreement, attached hereto as Exhibit C. For the sake of clarity, it is the intention of the parties that Executive will not incur a "separation from service" for purposes of this Paragraph 3.b.i. when or if Executive's em ployment with MarkWest Hydrocarbon, Inc. is transferred to the Company or its Affiliates so long as Executive continues to provide sufficient services to MarkWest Energy Partners, L.P. and certain related entities pursuant to Treasury Regulation 1.409A-l(h)(I)(ii) .

ii. Additional Long-Term Incentive Award . Executive shall be granted phantom partnership units of MPLX LP valued in the amount of $1,462,500 as of the actual grant date. As will be provided in the applicab le award agreement, the award will vest in three cumulative annual inst allm ent s, as follows: (1 ) one-third of the phantom partnership units shall vest on the first

anniversary of the grant date; (2) an additional one-third of the phantom partnership units sha ll vest on the second anniversary of the grant date; and (3) all remaining phantom partnership units shall vest on the third anniversary of the grant date; provided , however , that except as provided below or in the applicable award agreement, Executive must be providing continuous service to Marathon Petroleum Corporation or any of its subsidiaries or Affiliates from the grant date through the applicable vesting date in order for the p hantom partnership units to vest. No twithstanding the foregoing, the applicable award agreement will provide that the phantom partnership units contemplated under this Paragraph 3.b.ii shall become fully vested upon Executive's separation from service as a result of the forced relocation of Executi ve's principal place of em ployment to a location more than 50 miles from Executive's th en-current principal place of employment. The award of the phantom partnership unit s contemplated under this Paragraph 3.b.ii. shall be subject to the te rms and conditions of the MPLX LP 2012 Incentive Compensation Plan, attached hereto as Exhibit B, and the applicable award agreement, which shall be similar in form to the MPLX LP 2012 Incentive Compensation Plan Phantom Unit Award Agreement, attached hereto as Exhibit D.

iii. Retention Bonus Award . Executive shall be granted restricted stock of Marathon Petroleum Corporation, valued in the amount of $ 1,000,000 as of the actual grant date. As will be provided in the applicable award agreement, the award will vest in full on the third anniversary of the grant date; provided , however, that except as provided below or in the applicable award agreement, Executive must be providing continuous service to Marathon Petroleum Corporation or any of its subsidiaries or Affiliates from the grant date through the applica ble vesting date in order for the restricted stock award to vest. Notwithstanding the foregoing, the applica ble award agreement will provide that the restricted stock contemplated under this Paragraph 3.b.iii shall become f ully vested upon Executive's separation from service as a result of the forced relocation of Executive's principal place of employment to a location more than 50 miles from Executive's then-current principal place of employment. The award of restricted stock of Marathon Petroleum Corporation contemplated under this Paragraph 3.b.iii. shall be subject to the terms and conditions of the Marathon Petroleum Corporation 2012 Incentive Compensation Plan, as amended, attached hereto as Exhibit E, and the applicable awar d agreement, which shall be similar in form to the Marathon Petroleum Corporation 2012 Incentive Compensation Plan Restricted Stock Award Agreement, attached hereto as Exhibit F.

portion so delayed, s hall be m ade on the soonest date permissible without triggering the additional tax due under Section 409A of the Code.

Short-Term Incentives. During Executive's continued employment in a senior managemen t position , Executive shall be eligible to receive bonuses / short - term cash incentives in accordance with the Company's or its Affiliate's cash bonus / short-term incentive program(s) for senior management, as such programs may be modified from time to time. For the 2015 calendar year, Executive shall be entitled to a short-term cash bonus determined by the Company as of the Closing Date, under the performance metrics e sta blished by the MarkWest Hydrocarbon, Inc. short-term incentive plan and which shall be paid to Executive as soon as practicable following the end of the Partnership's 2015 calendar year, but within the first two weeks of calendar year 2016 .

Long-Term Incentives. Except as otherwise provided in this Paragraph 3.d., during Executive's continued employment in a senior management position, Executive shall be elig i b le to receive long-term incentive grants in the form of equity in accord ance with the Company's or its Affiliate's long-term incentive program(s) for senior management, as such progr ams may be modified from time to time. Executive will not receive a long-term incentive award in calendar year 2016 since a Lon g Term Incentive Award has been included in the Retention Bonus as set forth in Paragraph 3.b.


e.	Change-in-Control Severance Benefits. During Executive's continued employment in a senior management position, Executive shall be entitled to participate in t h e Marathon Petroleum Corporation Amended and Restated Executive Change in Control Severance Benefits Plan, under terms and conditions established by the Company.


f.	Savings and Retirement Plans. In addition to base salary and the bonuses, Executive shall be entitled to participate during Executive's continued employment with the Company in all savings and retirement plans, practices, policies and programs that are from time to time generally available to other similarly-situated, senior executives of the Company or its Affiliates.

Welfare Benefits. During Executive's continu ed employmen t with t he Company or its Affiliates, Executive and Executive's eligible dependents, as the case may be, shall be e ligible for participation in all benefits under welfare benefit plans, practices, policies, and programs provided by the Company or its Affiliates generally available to other similarly-situated, senior executives of the C om pany or its Affiliates.


h.	Fringe Benefits / Perquisites. During Executive's continued em ployment with

the Company or its Affiliates in a senior management position, Executive shall be entitled to all fringe benefits that are from time to time generally available to other similarly-situated, senior executives of the Company or its Affiliates.


i.	Vacation. Executiv e sha ll be en titled to the same amount of vacation as Executive received under the Mar kWest Hydrocarb on, Inc . vacation plan immediately prior to the Closing Date or such vacation time which is provided for similarly situated executives at the Company or its Affiliates under the Co m pany's or its Affiliate's vacation policy, whichever is greater.

Expenses. During Executive's continued employment with the Company or its Affiliates, Executive shall be entitled to receive prompt reimbursement for all reasonable employment related expenses incurred by Executive upon receipt by the Company or its Affiliate of accounting in accordance with practices, policies, and procedures generally available to other senior executives of the Company or its Affiliates, provided, that all reimbursements shall in any event be made within 2.5 months following the year in which they were incurred.


k.	Officers and Directors Liability Insurance; Indemnification. Executive shall receive coverage under the Company ' s and its Affiliates' indemnification and directors and officer s li a bility policies to the same extent that it provides su c h coverage to similarly-situated, senior executives of the Company or its Affiliates.


l.	Crediting of Prior Service . For the purpose of det e rminin g eligibility for Company and Affiliate compensation a nd benefits, vacation accruals, and vesting in savings and retirement plans, Executive shall be credited for any past service that was recognized by MarkWest Hydrocarbon, Inc.


4.	Termination of Employment .

Executive's continued employment with the Company and its Affiliates shall be "at will," meaning that Executive may resign for any reason without any resulting l ia bility to the Company or its Affiliates, and the Company may terminate (or cause the Executive's employer to terminate) Executive's employment for any reason, or no reason, with or without cause, without any resulting liability to Executive, except as expressly provided in this Retention Agreement.


b.	In addition to any amounts or benefits payable under this Retention Agreement, E x ecuti v e shall, except as otherwise specifically provided herein, be entitled to any payments or benefits provided under the terms of any p lan, policy or program of the Company or its Affiliates in which Executive participates or as otherwise re quir ed b y a pplicable law.

Restrictive Covenants . Executive acknowledges and agrees that the undertakings, covenants and agreements set forth in Section 7 of the Prior Agreement s hall survive and are incorporated by reference into this Retention Agreement. For these purposes, th e "Term" s hall be mean Executive's continued employment with the Company or its Affiliates under this Retention Agreement; the term "Board" sh al l mean the Company; the term "Company" shall mean the Company, as herein defined; and the term "MarkWest Parties" shall mean the Company and its Affiliates.


6.	Miscellaneous .


a.	T he Company may assign its rights and obligations un d er this Retention Agreement to any Affiliate. The Company may also assign its rights and obligations under this Retention Agreement to any successor entity wh ic h acquired a ll or substantially all of the assets of the Company, by merger or otherwise.


b.	This Retention Agreement shall be governed, construed, interpreted and enforc e d in accordance with the substantive laws of the state of Ohio, without reference to the principles of conflicts of law of Ohio or any other jurisdiction, and where ap pli ca bl e, the laws of the United States.

It is th e intention of the Parties that payments or benefits payable under this Retention Agreement not be subject to the additional tax imposed pursuant to Section 409A of the Code, and the provisions of this Retention Agreement shall be co nstru ed a nd a dministered in accordance with such intent. To the extent such po t e nt i al payments or be n efi t s co uld b ec om e s ubject to Section 409A of the Code , the Parties shall cooperate to amend this Retention Agreement with the intent of giving Exec ut ive the economic b enefi t s described he r ein in a manner that does not result in s uch tax being imposed . If the Parties are unable to agree on a mutually acceptable amendment, the Company may, without Executive's consent and in such ma nn er as it reaso n a bly deems appropriate or desirable, amend or modify this Retention Agreement or delay the payment of any amounts hereunder to the minimum extent necessary to meet the requirements of Section 409A of the Code. To the ex te n t req ui re d by Section 409A of the Code, if Executive is required to execute a re lease of claims, including the Release, as a condition to recei pt of any payments or benefits under this Retention Agreement, and the period during which Executive has to execute such release (including the Release) spans two cale nd ar years , s u ch p ay m ents a nd ben efits s h a ll be paid (or sh al l commence) in the se c ond calendar year. T he Company makes no representations or warranties as to whet her this Retention Agreement (or the Prior Agreement) complies with or is exe mp t fro m S ecti on 4 0 9A of th e Code. Executive acknowled ge s an d agrees that, with respect to issues of documentary compliance under Code Section 409A, (i) the Company and its Affiliates have no obligation to take any action to prevent the assessment of any additional income tax, interest or penalties imposed under Section 409A of the Code on any person (including

Executive), (ii) the Company and its Affiliates, and each of their employees and representatives shall not have any liability to Executive with respect thereto, and (iii) Executive will not make any claim against the Company or its Affiliates or any of their employees and representatives, for any liabilities, including for any additional income taxes, interest or penalties, that Executive may incur hereunder.

The terms of this Retention Agreement are intended by Executive and the Company to be the final expression of the Parties agreement with respect to matters addressed herein and may not be contrad ic ted by evidence of any prior or contemporaneous agreement, except as noted herein. F o r purposes of clarification , nothing in this Re t ention Agreement shall negate the obligations to Executive u n der Section 6 of the Prior Agreement with respect to payments Executive receives or is entitled to receive under Paragraph 3.b.i of this Retention Agreement and accelerated vesting of equity awards under any MarkWest Hydr oca rb on, Inc. or MarkWest Energy Partners, L.P. equity plan or under Section 3(c)(ii) of t h e Pr i or Ag r eeme n t, b ut t h ere shal l be no o bligations to Executive u n d e r Section 6 of t he Prior Agreement with respect to any other payments co nt e m p l a t e d under this Retention Agreement.

This Retention Agreement s u persedes al l p rior agreements between the Parties, an d between MarkWest Hydrocarbon, Inc . (or an Affiliate there o f) and Executive , concerning the subject matter hereof (including, but not limited to, salary, bo nuses , e quity awards, deferred compensation, and severance benefits (cash or n o n cas h )), a n d incl uding, but not limited to, that certain Retention Agreement dated as of July 11, 2015 (which agreement is hereby rescinded by the Parties) and the Prior Agreement (i.e., Executive's Emp loyment Agreement, dated September 5, 2007), except to the extent expressly provided herein.

This Retention Agreement may not be modified, amended, or terminated except by an instrument in writing, signed by Executive and a duly authorized officer of the Com pany except in the case of a cancellation of the Merge r in w hich case this Retention Agreement terminates without any required action on behalf of the Executive or the Company. By an instrument in writing similarly executed, Executive or a duly authorized officer of the Company may waive com pliance by the other Party or Parties with any provision of this Retention Agreement that such other party was or is obligated to comply with or perform, provided, however , that such waiver shall not operate as a waiver of, or estoppel with respect to, any other subsequent failure . N o failure to exercise and no delay in exerci si ng any r i g ht, remedy, or power hereunder preclude any other or further exercise of any other right, remedy, or power provided herein or by law or in equity.


g.	This Retention Agreement may be executed in one or more counterparts, each of which shal l be deemed to be an original but all of which together will constitute one and the same instrument.

IN WITNESS WHEREOF, this Retention Agreement has been executed to be effective as of the date and year first written above.



MARATHON PETROLEUM COMPANY LP

By	/s/ Gary R. Heminger
	Name:	Gary R. Heminger
	Title:	President and Chief Executive Officer of Marathon Petroleum Corporation


	EXECUTIVE
	/s/ Nancy K. Buese
	Nancy K. Buese

[Signature Page to Retention Agreement ]

EXHIBIT A

EMPL O YME N T AGREE M ENT

THIS EMPLOYMENT AGREEMENT (the “ Agreement ”) is made and entered into as of this 5 ^th day of September 2007 by and between MarkWest Hydrocarbon, Inc., a Delaware corporation, having its principal executive offices in Denver, Colorado (the “Company”) and Nancy K. Buese, residing in Evergreen, Colorado (the “Executive”).

WHEREAS , the Company derives its revenue and value through its natural gas liquids and gas marketing activities and through its ownership in MarkWest Energy Partners, L.P. (the " Partnership" ), a publicly traded Delaware master limited partnership engaged in the gathering, transportation and processing of natural gas, the transportation and fractionation and storage of NGLs, and the gathering and transportation of crude oil;

WHEREAS , the Company's ownership interest in the Partnership consists of ownership of an approximately 17% limited partner interest in MarkWest Energy Partners, L.P., and ownership of approximately 89.7% of MarkWest Energy GP, L.L.C. (the "GP"), the Partnership's general partner;

WHEREAS , the Company and GP have entered into a services agreement (the " Services Agreement" ) pursuant to which the Company acts in a management capacity providing day-to day operational, business and asset management, accounting, information services, personnel, and related administrative services to the Partnership;

WHEREAS , the Executive is currently serving as Senior Vice President and Chief Financial Officer of the Company, and in such capacity provides services to or on behalf of the Company and its affiliates, and to the Partnership and its affiliates pursuant to the Services Agreement; and

WHEREAS , the Company and the Executive mutually desire to formalize the employment arrangement of the Executive and to agree upon the terms of the Executive's employment as the Senior Vice President and Chief Financial Officer of the Company and, in addition, to agree as to certain benefits of said employment.

NOW, T HE REFORE , in consideration of the mutual promises and agreements set forth below, the Company and the Executive hereby agree as follows:

1. T ERM OF EMPLOYMENT : Subject to the terms of this Agreement, the Company hereby continues the employment of the Executive, and the Executive hereby accepts such continuing employment , effective September 5, 2007 (the " Effective Date" ), tor a period of three years, subject to earlier termination as provided in Paragraph 4, herein (the "Term"); provided, however, that the Term will automatically be extended by twelve months on the third anniversary of the Effective Date and on each anniversary of the Effective Date thereafter, unless one party to this Agreement provides written notice of non-renewal to the other party at least 30 days prior to the effective date of such automatic extension. The consequences of termination of employment to each party are as set forth in this Agreement. Portions of this Agreement that by their terms provide or imply that they survive the end of the Term shall survive the end of the Term.

2. POSITION AND DUTIES :

a. Positi o n : During the Term, the Executive shall serve as Senior Vice President and Chief Financial Officer of the Company and shall have such duties, responsibilities, and authority as are customarily required of and given to the Senior Vice President and Chief Financial Officer of a public mid-stream energy company. The Executive shall report directly to the Company's Chief Executive Officer and shall perform his or her duties and responsibilities primarily at the Company's offices in Denver, Colorado.

b. Commitment of the Executive : During the Term, the Executive shall devote substantially Executive's full business time, energy, and ability to the business of the Company, the Partnership, and their respective affiliates . As used in this Agreement, the term " Affiliate " means, with re s p ec t to any entity, any other entity that directly or indirectly controls, is controlled by, or is under common control with such first entity.

c. Other Positions and Services : The Executive may (i) with the prior written approval of the Company's Board of Directors (the " Board "), which approval shall not be unreasonably withheld or delayed, serve as a director or trustee of other for profit corporations or businesses, provided , that if a directorship is approved and the Board later determines (A) that the directorship would violate Paragraph 7 of this Agreement, or (B) that the Board no longer approves of the directorship, which approval shall not be unreasonably withdrawn, it shall notify the Executive in writing and the Executive shall resign such directorship within a reasonable period of time, (ii) serve on civic or charitable boards or committees, and (iii) deliver lectures, fulfill speaking engagements, or teach at educational institutions (and retain any fees therefrom); provided , however, that the Executive may not engage in any of the activities described in this Paragraph 2(c) to the extent such activities interfere materially with the performance of the Executive's duties and responsibilities to the Company.

d. Investments : Except as may otherwise be permitted by this Agreement, without the prior express authorization of the Board, the Executive shall not, during the Term, directly or indirectly render services of a business, professional, or commercial nature to any other person or firm, whether for compensation or otherwise. Notwithstanding the foregoing, the Executive may be an investor, shareholder, joint venturer, or partner in any such business (hereinafter referred to as "Investor"); provided , that Executive's status as an Investor shall not (i) pose a conflict of interest with regard to Executive's employment, (ii) require the Executive's active involvement in the management or operation of such Investment (recognizing that the Executive shall be permitted to monitor and oversee the Investment), or (iii) interfere materially with the performance of the Executive's duties and obligations hereunder. For the purposes of clause (i) of the preceding sentence, the Executive shall not be deemed to be subject to a conflict of interest merely by reason of the ownership of less than five percent (5%) of (i) the outstanding stock of any entity whose stock is traded on an established stock exchange or on the National Association of Securities Dealers Automated Quotation System, or (ii) the outstanding stock, partnership interests or other form of equity interest of any venture fund, investment pool or similar investment vehicle .

e. No Conflict : The Executive represents and warrants that, to the best of Executive ' s knowledge after the review of Executive's personal files, he has the full right and authority to enter into this Agreement and to render the services as required under this Agreement, and that by signing this Agreement and rendering such services he is not breaching any contract or legal obligation he owes to any third party.

3. COMPENSATION AND BENEFITS : During the Term, while the Executive is employed by the Company, the Company shall compensate the Executive for his or her services as set forth in this Paragraph 3. The Executive recognizes that during the Term of the Agreement, the Company reserves the right to change from time to time the terms and benefits of any retirement, welfare or fringe benefit plan of the Company, including the right to change any service provider, so long as such changes are also applicable generally to all executives of the Company.

a. Salary : During the Term, the Company shall pay the Executive a base salary at an annual rate of $250,000.00 (the " Base Salary" ). Base Salary shall be earned and shall be payable in periodic installments in accordance with the Company's payroll practices. Amounts payable shall be reduced by standard withholding and other authorized deductions. The Compensation Committee of the Board (the " Compensation Committee" ) will review the Executive's salary at least annually and may adjust the Executive's Base Salary in its sole discretion. Executive's salary as so adjusted shall thereafter be treated as Executive's Base Salary hereunder.

b. Cash Bonus / Short-Term Incentives : The Executive shall be eligible to receive bonuses/short-term cash incentives in accordance with the Company's cash bonus/short term incentive program(s) for senior management, as such program(s) may be modified from time to time. All bonuses/short-term cash incentives shall be paid in a manner that complies with the requirements of Section 409A of the Internal Revenue Code of 1986, as amended (the "Code").

c. E q u ity Compen s ation Programs :

(i) General . The Executive shall be entitled to participate in all equity compensation programs sponsored by the Company, the Partnership, or their Affiliates (the "Equity Plans"). The size and terms of any grants to be made to Executive shall be established by the Compensation Committee, or the Compensation Committee of the Partnership, in their sole discretion.

(ii) Change of Control . All grants made under the Equity Plans (including those made prior to the effective date of this Agreement) shall vest in full immediately prior to the occurrence of a Change of Control. For purposes of this Agreement, a Change of Control shall mean the first to occur of:

(A) any "person" (as defined in Section 13(d) and 14(d) of the Securities Exchange Act of 1934, as amended (the " Exchange Act ")) other than (1) the Company or any Affiliate of the Company as of the date of this Agreement, (2) any employee benefit plan of the Company or any Affiliate of the Company, or (3) any person or entity organized, appointed or established by the Company for or pursuant to the terms of any such plan which acquires beneficial ownership of voting securities of the Company, is or becomes the beneficial owner, directly or indirectly, of securities of the Company representing 50% or more of the combined voting power of the Company's then outstanding securities.

(B) the individual directors of the Board on the effective date of this Agreement (" Incumbent Directors ") cease to constitute at least two - thirds of the Board wi t hin any three ( 3) year period. For purposes of this paragraph , any new director whose election by the Board or nomination for election by the Company's stockholders was approved by a vote of at least two - thirds of the Incumbent Directors shall be considered an Incumbent Director. However, no director whose initial election to the Board occurs as a result of an actual or threatened election contest with respect to the election or removal of director or other actual or threatened solicitation of proxies or consents by or on behalf or a person other than the Board shall be considered an Incumbent Director;

(C) consummation of a reorganization, merger or consolidation of the Company (a " Business Combination "), in each case, unless, following such Business Combination, the individuals and entities who were the beneficial owners of outstanding voting securities of the Company immediately prior to such Business Combination beneficially own, by reason of such ownership of the Company's voting securities immediately before the Business Combination, directly or indirectly, more than 50% of the combined voting power of the then outstanding voting securities entitled to vote generally in the election of directors of the company resulting from such Business Combination (including, without limitation, a company which as a result of such transaction owns the Company or all or substantially all of the Company's assets either directly or through one or more subsidiaries) in substantially the same proportions as their ownership of the outstanding voting securities of the Company immediately prior to such Business Combination; or

(D) approval by the stockholders of the Company of a complete liquidation or dissolution of the Company.

(E) any sale, lease, exchange, or other transfer or disposition of all or substantially all of the assets of the Partnership or the GP;

(F) consummation of any Business Combination with respect to the GP, unless, following such Business Combination, the individuals and entities who were the beneficial owners of outstanding voting securities of the GP as of the initial public offering of securities in the Partnership, beneficially own, by reason of such ownership of the GP's voting securities, directly or indirectly, more than 50% of the combined voting power of the then outstanding voting securities entitled to vote generally in the election of directors of the company resulting from such Business Combination (including, without limitation, a company which as a result of such transaction owns the GP or all or substantially all of the GP's assets either directly or through one or more subsidiaries) in substantially the same proportions as their ownership of the outstanding voting securities of the GP as of the initial public offering of securities in the Partnership; or

(G) the general partner of the Partnership (whether it be the GP or another entity) ceases to be an Affiliate of the Company .

Notwithstanding the foregoing subparagraphs (A) through (G), in no event shall any transaction or series of transactions entered into between the Company, the Partnership, the GP, or their respective Affiliates as of the date of this Agreement or entities wholly owned by the forgoing, or changes associa t ed therewith, be considered a Change in Control.

d. Retirement Plans : The Executive shall be entitled to participate in all retirement plans applicable generally to other senior executives of the Company, in accordance with the terms of such plans, as they may be amended from time to time.

e. W elfare Benefit Plans : The Executive and Executive's family, as the case may be, shall be eligible to participate in and shall receive all benefits under the Company's welfare benefit plans and programs applicable generally to other senior executives of the Company (collectively, as amended from time to time, the "Company Plans"), in accordance with the terms of the Company Plans.

f. V a cation and Sick L eave : Executive shall be entitled to paid vacation, sick leave, and paid time off in accordance with the plans, policies, and programs in effect generally with respect to other senior executives of the Company, including the limitations, if any, on the carry-over of accrued but unused time.

g. E x penses : The Company shall reimburse the Executive for reasonable expenses for cellular telephone usage, entertainment, travel, meals, lodging, and similar items incurred in the conduct of the Company's business. Such expenses shall be reimbursed m accordance with the Company's expense reimbursement policies and guidelines.

h. Fringe Benefits and P erquisites : Executive and Executive's family, as the case may be, shall be eligible for all other fringe benefits or perquisites offered generally to senior executives of the Company (and their families, as applicable).

i. Officers and D irectors L iability I nsurance; I ndemnifica t io n : During Executive's employment w i th the Company and thereafter so long as Executive may have liability arising out of Executive's service as an officer or director of the Company or any Affiliate, the Company agrees to continue and maintain a director's and officer's liability insurance policy (" D&O Insurance" ) covering Executive in an amount that is reasonable and customary based on the size and business activities of the Company, the Partnership, and their Affiliates, and the authorities, power, responsibilities, and duties of Executive. To the fullest extent permitted by the indemnification provisions of the Company's governing instruments in effect as of the date of this Agreement and the indemnification provisions of the governing laws of the jurisdiction of the Company's formation in effect from time to time (collectively, the "Indemnification Provisions " ), and in each case subject to the conditions thereof, the Company shall (i) indemnify the Executive, as a director (if applicable) and officer of the Company or an Affiliate of the Company or a trustee or fiduciary of an employee benefit plan of the Company or an Affiliate of the Company, or, if the Executive shall be serving in such capacity at the Company's request, as a director or officer of any other entity (other than an Affiliate of the Company) or as a trustee or fiduciary of an employee benefit plan not sponsored by the Company or an Affiliate of the Company, against all liabilities and reasonable expenses that may be incurred by the Executive in any threatened, pending, or completed action, suit or proceeding, whether civil, criminal or administrative, or investigative and whether formal or informal, because the Executive is or was a director or officer of the Company or any Affiliate, a director or officer of such other entity or a trustee or fiduciary of such employee benefit p l an, and against which the Executive may be indemnified by the Company, and (ii) pay for or advance to Executive the reasonable expenses incurred by the Ex ecutive in the defense of any proceeding to which the Executive is a party because the Executive is or was a director or officer of the Company or an Affiliate, a director or officer of such other entity or a trustee or fiduciary of such employee benefit plan. The rights of the Executive under the Indemnification Provisions shall survive the termination of the employment of the Executive by the Company.

4. TERMINATION : The Executive's employment with the Company during the Term may be terminated by the Company or the Executive pursuant to this Paragraph 4, subject to the provisions of Paragraph 5:

a. De at h o r Disability : If the Executive has a Disability (as defined below), the Company may give to the Executive written notice of its intention to terminate the Executive's employment. In such event, the Executive's employment with the Company shall terminate effective on the 30th day after receipt of such notice by the Executive, provided that, within the 30 - day period after such receipt, the Executive shall not have returned to full-time performance of the Executive's material duties. For purposes of this Agreement, "Disability" shall mean any physical or mental condition which prevents the Executive, for a period of 90 consecutive days, from performing and carrying out Executive's material duties and responsibilities with the Company, as determined under the Company's long-term disability plan . The Executive's employment hereunder shall terminate automatically upon the Executive's death.

b. Cause : The Company may terminate this Agreement immediately upon written notice to the Executive if, after the Executive is given an opportunity to be heard by the Board and to present evidence on Executive's behalf, a formal determination is made by a majority of the directors on the Board and at least two-thirds of the Board's non-employee directors, that the Executive should be terminated for "Cause". Any one or more of the following events shall constitute " Cause ":

(i) conviction of (or pleading nolo contendere to) a felony that is injurious to the business or reputation of the Company, the Partnership, or their Affiliates;

(ii) engaging in intentional wrongdoing (including without limitation, theft, fraud, embezzlement, or willful misappropriation of the funds or property of the Company, the Partnership, or their Affiliates), or failure by Executive to substantially adhere to the Company work rules, policies or procedures, that is injurious to the business or reputation of the Company, the Partnership, or their Affiliates, or breach of fiduciary duties for enrichment of the Executive;

(iii) illegal or prohibited treatment of or relations with any employee, agent or consultant of the Company, the Partnership, or their Affiliates or of any person with whom the Company, the Partn e rship, or their Affiliates have a business relationship, in the form of illegal or prohibited discrimination, harassment, abuse, assault or other actions of a similar nature ;

(iv) Executive has failed to perform substantially Executive's material duties as contemplated by Paragraph 2 above (other than such failure resulting from incapacity due to physical or mental illness), which, for avoidance of doubt, shall include Executive's insubordination to his or her direct or indirect reports or to the Board, after (i) a written demand for corrected performance is delivered to Executive by the Board which identifies specifically the manners in which the Board believes Executive has not performed substan t ially Executive's material duties , and (ii) Execu t ive's failure to cure such items identified in the Board's letter within 30 days .

(v) any material breach of Executive's obligations under this Agreement including, but not limited to, a breach of Executive's obligations under Paragraph 7 ; provided, however, that in the event such breach is curable and is actually cured within ten (10) days after written notice detailing the nature and facts of such breach is delivered to Executive, the breach sha ll not be considered "Cause" for Executive's termination.

(vi) engaging in actions or behavior that bring Executive into public hatred, disreput e, scorn, or ridicule, or shock, insult, or offend the community or public morals or decency, in each case resulting in injury to the business or reputation of the Company or inhibiting the a bili t y of Executive to effectively represent publicly the Company, the Partnership, or their Affiliates .

c. Other than Death or Disability or Cause : The Company may terminate the Executive's employment upon thirty (30) days written notice to the Executive at any time and f or any reason other than Death, Disability, or Cause.

d. T ermination by E x ecutive : The Executive may terminate Executive's employment upon thirty (30) days written notice to the Company at any time and for any reason.


5.	OB LIGATIONS OF THE COM PAN Y A N D THE EXE C UTIVE UPON TERMI N AT I ON :

a. Death or Disability : If the Executive's employment is terminated by reason of the Executive's death or Disability during the Term, the Term shall end and the Company shall provide to Executive or Executive's legal representatives:

(i) payment of the sum of (A) any Base Salary and bonus earned but not yet paid to the Executive through the date of termination, and (B) any other compensation earned through the date of termination but not yet paid or delivered to the Executive (" Accrued Obligations " ) ,

(ii) the payments and benefits provided in P a ragraph 5(g),

(iii) payment to the Executive of a lump sum equal to (A) 24 months of the E xecutive's then current Base Salary , (B) two (2) times the average annual bonus earned by the Executi v e f o r the tw o mos t recentl y completed fiscal years, and (C) a pro-rata portion of the target amount of the annual bonus for the fiscal year of termination, calculated based on the portion of such fiscal year the Executive is employed. The lump sum payment shall be made w ithin thirty (30) days o f t er minat i on or, i f the paym e nt , or any portion thereof , must be delayed t o c ompl y wi t h C ode Secti o n 409A becau se the indi v idual is a "sp e cified employe e" as defined in Code Section 409(A)(a)(2)(B)(i), the payment, or the portion so delayed, shall be made on the soonest date permissible without triggering the additional tax due under Code Section 409A;

(iv) subject to Paragraph 3(c), the accelerated vesting of each stock option or unit option, phantom unit, restricted stock or restricted unit, or other equity incentive award granted under the Equity Plans (or portion thereof) that would have otherwise vested solely upon the Executive remaining in the continuous employment of the Company for a period of twelve (12) months after the date of termination, and

(v) payment of all premiums for properly elected group health plan continuation coverage for Executive and his or her spouse and dependents pursuant to the Consolidated Omnibus Budget Reconciliation Act of 1985 (" COBRA" ) for the lesser of (A) the number of months of Base Salary to be paid to Executive under subparagraph (iii)(A), above, or (B) the duration of such COBRA coverage. All such premiums shall be paid on the first day of the month . In addition, in the event that payment of such premiums is taxable to executive, the Company shall pay to Executive an amount, as and when such premiums are paid, such that after taking into account all taxes due on the premiums and on the additional payment, the Executive will be in the same economic position as he would have been in had such premiums been non- taxable.

The Company shall be obligated to make the foregoing payments and to provide the foregoing benefits upon the Executive (or, if applicable, the Executive's l egal representative) and the Company signing a mutual release (the " Release" ) of all claims (including claims by, on behalf of, or against the Partnership, any Affiliates of the Partnership or the Company, and their respective directors, agents, employees, and assigns) in a form provided by the Company, which release shall, if applicable, give the Executive appropriate notifications under the Age Discrimination in Employment Act, as amended by the Older Workers Benefit Protection Act, and which shall not affect (x) rights under COBRA and (y) conversion rights under any applicable life insurance policies.

b. T e r mi n a t i on for Cause : If the Executive's employment i s terminated by the Company for Cause, the Term shall terminate without further obligations to the Executive under this Agreement after the date of such termination, other than for (i) payment of the Accrued Obligations, and (ii) the payments and benefits provided in Paragraph 5(h).

c. Other than Death or Disability or Cause : If the Company terminates the Executive's employment during the Term for any reason other than Death, Disability, or Cause, the Term shall end on the date of such termination and the Executive shall, upon signing of a Release, be entitled to the payments, benefits and other comp e nsation provided above in Paragraph 5(a).

d. Voluntary Termination by Executive : If the Executive terminates his or her employment without Good Reason, as defined below, the Term shall end and the Company shall provide to Executive:

(i) the Accrued Obligations

(ii) the payments and benefits provided in Paragraph 5(h)

(iii) if the Executive's total, aggregate term of employment with the Company (notwithstanding any breaks in service) exceeds one (1) year, then upon signing a Release, the Executive shall also receive:

(A) a lump sum payment equal to three (3) months of the Executive's then current Base Salary, which amount shall be paid within ten (10) days of termination or, if the payment, or any portion thereof, must be delayed to comply with Code Section 409A because the individual is a "specified employee" as defined in Code Section 409A(a)(2)(B)(i), the payment, or the portion so delayed, shall be made on the soonest date permissible without triggering the additional tax due under Code Section 409A;

(B) payment of all premiums for properly elected COBRA coverage for Executive and his or her spouse and dependents for the lesser of (A) the number of months of Base Salary to be paid to Executive under subsection (d)(iii)(A), above, or (B) the duration of such COBRA coverage.


e.	Term in at i o n by Executive for Good Reason :

(i) In General . If the Executive terminates his or her employment for Good Reason, as defined below, the Term shall terminate on the date of such termination and the Executive shall, upon signing a Release, be entitled to the payments, benefits and other compensation provided above in Paragraph S(a).

(ii) " Good Reason ". For purposes of this Agreement, the Executive's termination of employment with the Company shall be on account of "Good Reason" if it occurs for any of the following reasons: (A) any failure by the Company to comply with any of the provisions of Paragraph 3 of this Agreement, including but not limited to the failure by the Company to pay to the Executive any portion of his or her compensation in violation of the provisions of Paragraph 3, other than an isolated, insubstantial and inadvertent failure not occurring in bad faith and which is remedied by the Company promptly after receipt of notice thereof given by the Executive; (B) a material diminution in Base Salary or bonus opportunity not related to performance or market conditions, other than which is remedied by the Company within thirty (30) days after receipt of notice thereof given by the Executive; (C) a material diminution in responsibility or authority other than which is remedied by the Company within thirty (30) days after receipt of notice thereof given by the Executive; (D) the forced relocation of Executive's principal place of employment to a location more than 50 miles from the Executive's then-current principal place of employment; or (E) the occurrence of a Change of Control, provided that Executive voluntarily terminates his or her employment within twelve ( 12) months of the Change of Control.

f. Expiration of Term . In the event that the Term expires following the giving of notice of non-renewal pursuant to Paragraph 2, above, then (i) if such notice was given by the Company, the termination shall be deemed to be for "Other than Death or Disability or Cause" and Executive shall , upon signing a Release, be entitled to the payments, benefits, and other compensation provided in Paragraph 5(a) above, and (ii) if such notice was given by the Executive, the termination shall be deemed a "Voluntary Termination by Executive" and Executive shall, upon signing a Release, be entitled to the payments, benefits, a nd other compensation provided in Paragraph 5(d) above .

g. General Partner Membershi p Interes t :

(i) Limited Applic a t i on . The provisions of Paragraph 5(g)(ii) below shall apply solel y in the event that the Company and the Partnership announce formall y to the public (whether through a press release or the filing of a current report on Form 8-K) that they no longer intend to pursue the proposed acquisition/business combination/restructuring transaction that was announced formally to the public on Februar y 21, 2007.

(ii) Repurchase of General Partner Membership Inter e st. Executive is hereby granted the option to elect at any time, by written notice to the Company, to cause the Company to purchase all, but not less than all of Executiv e 's Class B membership interest in MarkWest Energy GP, L.L.C. at the price established pursuant to the formula set forth in the GP LLC Agreement as of the delivery date of Executive's election notice (" Election Date "). If the Executive makes such election , the Company shall purchase the Executive' s Class B membership interest within thirty (30) days following the Election Date, such purchase price to be paid , at Compan y 's election , either (i) in full in cash by wire transfer of immediately available funds; or (ii) by a combination of cash and of common units of the Partnership, with a value for the common units as of the Election Date based on the closing price of the Partnership's common units for the twenty trading days prec e ding the Election Date, with the combination of cash and Partnership common units being equal to the price established pursuant to the formula set forth in th e GP LLC Agreement, provided that the value of the Partnership common units cannot comprise more than 50% of the purchase price established pursuant to the f ormula set forth in the GP LLC Agreement.

h. Exclusive R emedy : Except for the payments and benefits provided in this Paragraph 5, and under Pa r agraph 3(c), the Executive acknowledges and agrees that upon termination of the Term, he shall have no other claims against, and shall be entitled to no other payments or benefits from the Company under this Agreement or pursuant to the Company's policies and plans, other than (A) the Executive's rights under COBRA, (B) any conversion rights under any applicable life insurance policies, (C) payment of any amounts due pursuant to the terms of any equity-based plan of the Company or any welfare or retirement plan of the Company as of the date of termination or which by their specific terms extend beyond such date of termination, and (D) rights with respect to D&O Insurance and / or the In d emnification Provisions. The Executive and the Company have agreed that Executive will not participate in either the M a rkWest Hydrocarbon Inc. 1997 Severance Plan or the MarkWest Hydrocarbon, Inc. 2007 Severance Plan. In lieu of participation in such Severance Plans, the parties have agreed that the Executive will receive certain other payments and benefits as set forth in this Agreement. In no event shall the Executive be oblig a ted to seek other employment or take a ny other action by way of mitigation of the amounts payable to the E x ecutive under any of the provisions of this Agreement and such amounts shall not be reduced whether or not the Executive obtains other employment.

i. Resignations : On and as of the date that the employment of the Executive by the Company shall terminate for any reason, the Executive shall, if applicable, resign from his or her position as a director and officer of the Company or the Partnership, resign from all other positions he or she holds as a director, officer or employee of any subsidiary or Affiliate of the Company or the Partnership, and resign as a named fiduciary of any employee benefit plans sponsored by the Company or the Partnership or their subsidiaries or Affiliates.

6. 280G Provisions .

a. Determination; Efficient Gross-Up : If it is determined that any payment or benefit provided to or for the benefit of the Executive (a " Payment "), whether paid or payable or distributed or distributable pursuant to the terms of this Agreement or otherwise, would be subject to the excise tax imposed by Code section 4999 or any interest or penalties with respect to such excise tax (such excise tax together with any such interest and penalties, shall be referred to as the " Excise Tax "), then a calculation shall first be made under which such payments or benefits provided to the Executive are reduced to the extent necessary so that no portion thereof shall be subject to the Excise Tax (the "4999 Limit"). The Company shall then compare (a) the Executive's Net After-Tax Benefit (as defined below) assuming application of the 4999 Limit with (b) the Executive's Net After-Tax Benefit without application of the 4999 Limit. "Net After-Tax Benefit" shall mean the sum of (i) all payments that Executive receives or is entitled to receive that are contingent on a change in the ownership or effective control of the Company or in the ownership of a substantial portion of the assets of the Company within the meaning of Code section 280G(b)(2), less (ii) the amount of federal, state, local, employment, and Excise Tax (if any) imposed with respect to such payments. In the event (a) is greater than (b), Executive shall receive Payments solely up to the 4999 Limit and Executive shall choose which payments shall be reduced and the amount of the reduction of each payment. In the event (b) is greater than (a), then the Executive shall be entitled to receive all such Payments along with an additional payment (a " Gross-Up Payment ") in an amount such that after payment by the Executive of all taxes (including any interest or penalties imposed with respect to such taxes), including, without limitation, any income taxes (and any interest and penalties imposed with respect thereto) and Excise Tax imposed upon the Gross-Up Payment, the Executive retains an amount of the Gross-Up Payment equal to the Excise Tax imposed upon the Payments .

b. Calculations : All determinations required under this Paragraph 6, including the determination of whether a Payment is subject to the Excise Tax or the amount of any required Gross-Up Payment, shall be made by tax counsel, a nationally recognized certified public accounting firm not serving as auditor for the Company, or another tax professional with experience in such calculations, as selected by the Company and reasonably acceptable to the Executive (the " Tax Professional" ). The Tax Professional shall provide detailed supporting calculations for its determinations both to the Company and the Executive within fifteen days of receipt of any Payment, or such sooner period as may be requested by the Company. All costs relating to the Tax Professional shall be borne exclusively by the Company. Subject to Paragraph 6(d), below, any determination by the Tax Professional shall be binding upon the Company and the Executive.

c. Payment of Gross-Up : Any Gross-Up Payment, as determined pursuant to this Paragraph 6, shall be paid by the Company to the Executive within five business days of the receipt of the Tax Professional's determination, but in no event later than the end of Executive's taxable year next following the taxable year in which the original Excise Tax on the Payments is remitted to the Internal Revenue Service. As a result of the uncertainty in the application of Section 4999 of the Code at the time of the initial determination by the Tax Professional hereunder, it is possible that a Gross-Up Payment which will not have been made by the Company should have been made (“ Underpayment ”). In the event that the Company exhausts its remedies pursuant to Paragraph 6(d) and the Executive thereafter is required to make a payment of any Excise Tax, the Tax Professional shall determine the amount of the Underpayment that has occurred and any such Underpayment shall be promptly paid by the Company to or for the benefit of the Executive, but in no event shall such payment be made later than the end of Executive’s tax year following the tax year in which the Excise Tax is remitted to the Internal Revenue Service.

d. Tax Controversy : The Executive shall notify the Company in writing of any claim by the Internal Revenue Service that, if successful, would require the payment by the Company of an Underpayment. Such notification shall be given as soon as practicable but no later than ten business days after the Executive is informed in writing of such claim and shall apprise the Company of the nature of such claim and the date on which such claim is requested to be paid. The Executive shall not pay such claim prior to the expiration of the thirty - day period following the date on which it gives such notice to the Company (or such shorter period ending on the date that any payment of taxes with respect to such claim is due). If the Company notifies the Executive in writing prior to the expiration of such period that it desires to contest such claim, the Executive shall:

(i) give the Company any information reasonably requested by the Company relating to such claim,

(ii) take such action in connection with contesting such claim as the Company shall reasonably request in writing from time to time, including, without limitation, accepting legal representation with respect to such claim by an attorney reasonably selected by the Company,

(iii) cooperate with the Company in good faith in order effectively to contest such claim, and

(iv) permit the Company to participate in any proceedings relating to such claim;

provided, however, that the Company shall bear and pay directly all costs and expenses (including additional interest and penalties) incurred in connection with such contest and shall indemnify and hold the Executive harmless, on an after-tax basis, for any Excise Tax or income tax (including interest and penalties with respect thereto) imposed as a result of such representation and payment of costs and expenses. Without limitation on the foregoing provisions of this Paragraph 6(d), the Company shall control all proceedings taken in connection with such contest and, at its sole option, may pursue or forgo any and all administrative appeals , proceedings, hearings and conferences with the ta x ing authority in respect of such claim and may, at its sole option, either d irect the Executive to pay the tax claimed and sue for a refund or to contest the claim in any permissible manner , and the Executive agrees to prosecute such contest to a determination before any administ ra tive tribunal, in a court of initial jurisdiction and in one or more appellate courts, as the Company shall determ i ne; provided, however , that if the Company directs the Executive to pay such claim and sue for a refund, the Company shall advance the amount of such payment to the Executive, on an interest - free basis and shall indemnify and hold the Executive harmless, on an after-tax basis, from any Excise Tax or income tax (including interest or penalties with respect thereto) imposed with respect to such advance or with respect to an y imputed income with respect to such advance; and further provided that any extension of the s t atute of limitations relating to payment of taxes for the taxable year of the Executive with respect to w hi c h s uch contested amount is claimed to be due is limited solely to such contested amount. F urthermore, the Company's control of the contest shall be limited to issues with respect to which a Gross - Up Payment would be payable hereunder and the Executive shall be entit l ed to settle or contest, as the case may be, any other issue raised by the Internal Revenue Service or any other taxing authority.

e. Refunds; Etc. : If, after the receipt by the Executive of an amount advanced by the Company pursuant to Section 6(d), the Executive becomes entitled to receive any refund with respect to such claim , the Executive shall (subject to the Company's complying with the requirements of Section 6(d)) promptly pay to the Company the amount of such refund (together with any interest paid or credited thereon after t a xes a pplicable thereto). If, after the r e c e ipt by the Executive of an amount advanced by the Company pursuant to Section 6(d) , a determination is made that the Executive shall not be entitled to any refund with respect to such claim and the Company does not notify the Executive in writing of its intent to contest such denial of refund prior to the expiration of thirty days after such determination , then such advance shall be forgiven and shall not be required to be repaid and the amount of such advance s hall offset, to the extent thereof, the amount of Underpayment required to be paid.

7. CONFIDEN TIAL INFORMATION;NON-CO M PE T ITION , NON- SOL ICIT A TION :

a. Confidential I nformation : Except as permitted or directed by the Board, during the Term or at any time thereafter, Executive shall not divulge, furni s h, make accessible to anyone, lay claim to, attempt to lay claim to or use, or attempt to use, in any way (other than in the ordinary course of the business of the Company) any confidential or secret knowledge or information of the Company, the Partnership, or their respective Affiliates (collectively the "MarkWest Parties") that Executive has acquired or become acquainted with or will acquire or become acquainted with during the period of Executive's employment by the Company, whether developed by himself or by others, concerning any pricing information, trade secrets, confidential or secret plans or material (whether or not patented or patentable) directly or indirectly useful i n any aspect of the business of the MarkWest Parties, any customer or dealer lists of the MarkWest Parties, any confidential or secret development of the MarkWest Parties, or any other confidential information or secret aspects of the business of the MarkWest Parties (collectively, "Confidential Information"). Executive acknowledges that the Confidential Information constitutes a unique and valuable asset of the MarkWest Parties and represents a substantial investment of time and expense by the MarkWest Parties, and that any disclosure or other use of the Confidential Information other than for the sole benefit of the MarkWest Parties would be wrongful and would cause irreparable harm to the MarkWest Parties. Both during and after the Term, Executive shall refrain from any acts or omissions that would reduce the value of the Confidential Information. The foregoing obligations of confidentiality shall not apply to any knowledge or information that is now published or that s ub s equentl y becomes generally publicly known in the form in which it w a s obtained from the MarkWest Parties, oth e r than as a direct or indirect result of the breach of this Agreement by Executive; is lawfully obtained by Executive fr o m a th i rd party , pro v ided th a t Recipient did not have a ctual knowledge tha t such third party was restricted or prohibited from disclosing such information to Executive; or was independently developed by Executive, without use of any information obtained from Company. At the time of the termination of Executive's employment, or at such other time as the Company may request, Employee shall return all memoranda, notes, plans, records, computer tapes and software and other documents and data (and copies th e r e of) relating to Confidential Information that Executive may then possess or have under his or her control.

b. Non-competition; Non-solicitation : Executive understands and agrees that, in addition to Employee’s exposure to Confidential Information, Executive may, in his or her capacity as an employee, at times meet with the MarkWest Parties’ current or prospective customers, suppliers, partners, licensees or other business relations (collectively, "Business Relations" ) on behalf of the MarkWest Parties, and that, as a consequence of using or associating himself with the MarkWest Parties' name, goodwill, and professional reputation, Executive's employment shall place him or her in a position where Executive can develop personal and professional relationships with the MarkWest Parties' current and prospective customers. Executive further acknowledges that, during the course and as a result of Executive's employment, Executive has been or may be provided certain specialized training or know-h ow . Executive understands and agrees that this goodwill and reputation, as well as Executive's knowledge of Confidential Information and specialized training and know-how, could be used unfairly in competition against the MarkWest Parties. Accordingly, in consideration of the employment of Executive by the Company pursuant to this Agreement, Employee agrees that:

(i) during the time period commencing on the date hereof and terminating six (6) months after the end of the Term, Executive shall not directly or indirectly, individually or collectively in conjunction with others, engage in activities that compete with the business that the MarkWest Parties is engaged in at the time of the termination of Executive's employment in whatever geographic regions the MarkWest Parties engages in such business at such time (currently natural gas and refinery off-gas gathering and transportation, natural gas and refinery off-gas processing, off-gas and NGL frac t ionation, NGL, natural gas and derived products marketing, and related services, conducted in the southern Appalachian region of Kentucky, West Virginia, and southern Ohio, in the southwest and mid-continent regions of Oklahoma, Texas, Louisiana, Mississippi, and New Mexico, on the Gulf Coast, and in western Colorado/eastern Utah area); or

(ii) during the time period commencing on the date hereof and terminating eighteen (18) months after the end of the Term, Executive shall not directly or indirectly through another entity or person (i) induce or attempt to induce any employee of the MarkWest Parties to leave the employ of the MarkWest Parties, (ii) solicit to hire any person who was employed by the MarkWest Parties at any time during the one-year period immediately preceding the termination of Executive's employment with the Mar k West Pa rties, or (iii) induce or attempt to induce any current or prospective Business Relation of the MarkWest Parties (including, without limitation, any business entity that the MarkWest Parties have contacted in order to make a proposal to enter into a business relationship) to withdraw, curtail or cease doing business with the MarkWest Parties; provided , however, that Executive shall not be in breach of this paragraph in the event that any entity with whom Executive is employed or otherwise affiliated solicits or hires any person so long as Executive is not consulted concerning or otherwise involved, directly or indirectly, in such solicitation and/or hiring (except for involvement in a general administrative or other perfunctory manner), nor shall Executive be in breach of this paragraph in the event that any person applies for or inquires concerning employment in response to any advertisement or other job posting directed to the public in general, so long as Executive is not consulted concerning or otherwise involved, directly or indirectly, in any aspect of the recruitment, evaluation or hiring of the person(s) in question (except for involvement in a general administrative or other perfunctory manner).

Executive acknowledges that as an executive of a public company he falls within the exception to C.R.S 8 - 2 - 113(2)( d), which exempts executive and management personnel and officers from the prohibitions of non-compete provisions . Executive further agrees, during the period for which Executive has continuing obligations under this Paragraph 7(b), to inform any new employer or other person or entity with whom Executive enters into a business relationship, before accepting employment or entering into a business relationship, of the existence of this Agreement and give such employer, person other entity a copy of this Paragraph 7(b).

c. T hird-Party Beneficiaries : It is the express intent of the parties that the provisions of this Paragraph 7 may be enforced by any of the MarkWest Parties, and that the protections afforded herein shall inure to such MarkWest Parties as intended third-party beneficiaries.

d. Severability : To the extent that any provision of this Paragraph shall be determined to be invalid or unenforceable, the invalid or unenforceable portion of such provision shall be deleted from this Agreement, and the validity and enforceability of the remainder of such provision and of this Paragraph shall be unaffected. In furtherance of and not in limitation of the foregoing, it is expressly agreed that, should the duration of or geographical extent of, or business activities covered by, the noncompetition and non-solicitation agreements contained in Paragraph 7(b) be determined to be in excess of that which is valid or enforceable under applicable law, then such provision shall be construed to cover only that duration, extent, or those activities which may validly or enforceably be covered. Executive acknowledges the uncertainty of the law in this respect and expressly stipulates that this Paragraph shall be construed in a manner which renders its provisions valid and enforceable to the maximum extent (not exceeding its express terms) possible under applicable law.

e. Injunctive Relief : Executive agrees that it would be difficult to compensate the MarkWest Parties fully for damages for any violation of the provisions of this Paragraph 7. Accordingly, Executive specifically agrees that the MarkWest Parties shall be entitled to temporary and permanent injunctive relief to enforce the provisions of this Paragraph and that such relief may be granted without the necessity of proving actual damages. This provision with respect to injunctive relief shall not, however, diminish the right of the MarkWest Parties to claim and recover damages in addition to injunctive relief.

8. SU CC ESS O RSH IP : This Agreement shall inure to the benefit of and be binding upon the Company and its successors and permitted assigns and any such successor or permitted assignee shall be deemed substituted for the Company under the terms of this Agreement for all purposes. As used herein, “successor” and “assignee” shall be limited to any person, firm, corporation, or other business entity which at any time, whether by purchase, merger, reorganization, or otherwise, directly or indirectly acquires the stock of the Company or to which the Company assigns this Agreement by operation of law or otherwise in connection with any sale of all or substantially all of the assets of the Company, provided that any successor or permitted assignee promptly assumes in a writing delivered to the Executive this Agreement and, in no event , shall any such succession or assignment release t he Company from its obligations thereunder. The Company will require any successor (whether direct or indirect, by purchase, merger, consolidation or otherwise) to all or substantially all of the business and/or as s ets of the Company to assume expressly and agree to perform this Agreement in the same manner and to the same extent that the Company would be required to perform it if no such succession had taken place . As used in this Agreement, "Company" sh a ll mean the Company as herein before defined and any successor to its business and / or assets as aforesaid which assumes and agrees to perform this Agreement by operation of law or otherwise .

9. DISP U TE RESOLUTION : An y claim arising out of or in a ny way relating to this Agreement or the termination thereof shall be initiated in the federal or state courts for Denver, Colorado and both Executive and the Company (and the MarkWest Parties, as applicable) hereby submit to the jurisdiction of such courts. Each party shall be responsible for the payment of its own attorneys' fees; provided , however, that, the Company shall reimburse the Executive for all reasonable legal fees incurred by Executive for any claim arising out of or in any way relating to events occurring on and after a Change in Control, except any such claim initiated by Executive that is found to be frivolous or vexatious.

10. GOVERNING LAW : The provisions of this Agreement shall be construed in accordance with, and governed by, the laws of the State of Colorado without regard to principles of conflict of laws.

11. SAVINGS CLAUSE : If any provision of this Agreement or the application thereof is held invalid, the invalidity shall not affect other provisions or applications of the Agreement which can be given effect w i thout the invalid provisions or applications and to this end the provisions of this Agreement are declared to be severable.

12. WAI VER OF BREAC H : No waiver of any breach of any term or provision of this Agreement shall be construed to be, nor shall be, a waiver of any other breach of this Agreement. No waiver shall be binding unless in writing and signed by the party waiving the breach.

13. MODIFICATION : No provision of this Agreement may be amended, modified, or waived except by written agreement signed by the parties hereto.

14. ASSIGNMENT OF AGREEMENT : The Executive acknowledges that Executive's services are unique and personal. Accordingly, the Executive may not assign Executive's rights or del e g a t e Executiv e 's duties or obligations under this Agreement to any person or entity; provided , however, that payments may be made to the Executive's estate or beneficiaries as expressly set forth herein.

15. EN TI R E AGREEME N T : This Agreement is an integrated document and constitutes and contains the complete understanding and agreement of the parties with respect to the subject matter addressed herein, and supersedes and replaces all prior negotiations and agreements, whether written or oral, concerning the subject matter hereof.

16. CONST RUC T ION : Each party has coop e rated in the drafting and preparation of this Agreement. Hence, in any construction to be made of this Agreement, the sam e shall not be construed against any party on the basis tha t the party was the drafter. The captions of this Agreement are not part of the provisions and shall have no force or effect.

17. NOTICES : Notices and all other communications provided for in this Agreement shall be in writing and shall be delivered personally or sent by registered or certified mail, return receipt requested, postage prepaid, or sent by facsimile or prepaid overnight courier to the parties at the addresses set forth below (or at such other addresses as shall be specified by the parties by like notice). Such notices, demands, claims, and other communications shall be deemed given:

a. in the case of delivery by overnight service with guaranteed next day delivery, such next day or the day designated for delivery;

b. in the case of certified or registered United States mail, five days after deposit in the United States mail; or

c. in the case of facsimile, the date upon which the transmitting party received confirmation of receipt by facsimile, telephone, or otherwise; and

d. in the case of personal delivery, when received.

Communications that are to be delivered by the United States mail or by overnight service are to be delivered to the addresses set forth below:


(i)	To the Company:

MarkWest Hydrocarbon, Inc.

Attn: General Counsel

1515 Ar a p a hoe Street, Tower 2, Suite 700

Denver, CO 80202


(ii)	To the Executive:

Nancy K. Buese

1372 Bross Ct.

Evergreen, CO 80439

Each party, by written notice furnished to the other party, may modify the acceptable delivery address, except that notice of change of address shall he effective on ly upon receipt. In the event that the Company is aware that the Executive is not at the location when notice is being given, notice shall be deemed given when received by the Executive, whether at the aforementioned location or at another location.

18. T AX W I T HHOLD IN G : The Company may withhold from any amounts payable under this Agreement such federal, state, or local taxes as shall be required to be withheld pursuant to any applicable law or regulation.

19. REPRESENTATI O N : The Executive represents that he is knowledgeable and sophisticated as to business matters, including the subject matter of this Agreement, that he has read this Agreement and that he understands its terms. The Executive acknowledges that, prior to assenting to the terms of this Agreement, he has been given a reasonable time to review it, to c onsult with counsel of Executive's choice, and to negotiate at arm' s - length with the Company as to its contents . The Executive and the Company agree that the language used in this Agreement is the language chosen by the parties to express their mutu al intent, and that they have entered into this Agreement freely and voluntarily and without pressure or coercion from anyone .

20. 409A SAVINGS CLAUSE : It is the intention of the parties that payments or benefits payable under this Agreement not be subject to the additional tax imposed pursuant to Section 409A of the Code, and the provisions of this Agreement shall be construed and administered in accordance with such intent. To the extent such potential payments or benefits could become subject to Code Section 409A, the parties shall cooperate to amend this Agreement with the goal of giving Executive the economic benefits described herein in a manner that does not result in such tax being imposed. If the parties are unable to agree on a mutually acceptable amendment, the Company may, without the Executive's consent and in such manner as it deems appropriate or desirable, amend or modify this Agreement or delay the payment of any amounts hereunder to the minimum extent necessary to meet the requirements of Code Section 409A.

IN WITNESS WHEREOF, the Company and the Executive, intending to be legally bound, have executed this Agreement on the day and year first above written.



MARKWEST HYDROCARBON, INC.

By	/s/ Frank M. Semple
	Name:	Frank M. Semple
	Title:	President and Chief Executive Officer


	EXECUTIVE
	/s/ Nancy K. Buese
	Nancy K. Buese

EXHIBIT B

Exhibit 10.3

MPLX LP

2012 INCENTIVE COMPENSATION PLAN

1. Objectives . This MPLX LP 2012 Incentive Compensation Plan (the “Plan”) has been adopted by MPLX GP LLC, a Delaware limited liability company (the “Company”), the general partner of MPLX LP, a Delaware limited partnership (the “Partnership”) in order to compensate Employees, Officers and Directors with a high degree of training, experience and ability; to attract new Employees, Officers and Directors whose services are considered particularly valuable to the business of the Company; to encourage the sense of proprietorship of such persons; and to promote the active interest of such persons in the development and financial success of the Partnership, the Company and their Affiliates. These objectives are to be accomplished by making Awards under this Plan and thereby providing Participants with a proprietary interest in, and alignment with, the growth and performance of the Partnership, the Company and their Affiliates.

2. Definitions . As used herein, the terms set forth below shall have the following respective meanings:

“ Affiliate ” means, with respect to any Person, any other Person that directly or indirectly through one or more intermediaries controls, is controlled by or is under common control with, the Person in question. As used herein, the term “control” means the possession, direct or indirect, of the power to direct or cause the direction of the management and policies of a Person, whether through ownership of voting securities, by contract or otherwise.

“ ASC Topic 718 ” means Accounting Standards Codification Topic 718, Compensation – Stock Compensation , or any successor accounting standard.

“ Authorized Officer ” means the Chief Executive Officer of the Company (or any other officer of the Company to whom he or she shall delegate).

“ Award ” means an Option, Restricted Unit, Phantom Unit, DER, Substitute Award, Unit Appreciation Right, Other Unit-Based Award, Performance Unit or Profits Interest Unit granted under the Plan.

“ Award Agreement ” means the written or electronic agreement by which an Award shall be evidenced.

“ Board ” means the board of directors or board of managers, as the case may be, of the Company.

“ Cause ” means, unless otherwise set forth in an Award Agreement or other written agreement between the Company and the applicable Participant, a finding by the Committee, before or after the Participant’s termination of Service, of: (i) any material failure by the Participant to perform the Participant’s duties and responsibilities under any written agreement between the Participant and the Company or its Affiliate(s); (ii) any act of fraud, embezzlement, theft or misappropriation by the Participant relating to the Company, the Partnership or any of their Affiliates; (iii) the Participant’s commission of a felony or a crime involving moral turpitude; (iv) any gross negligence or intentional misconduct on the part of the Participant in the conduct of the Participant’s duties and responsibilities with the Company or any Affiliate(s) of

the Company or which adversely affects the image, reputation or business of the Company, the Partnership or their Affiliates; or (v) any material breach by the Participant of any agreement between the Company or any of its Affiliates, on the one hand, and the Participant on the other. The findings and decision of the Committee with respect to such matter, including those regarding the acts of the Participant and the impact thereof, will be final for all purposes.

“ Change in Control ” shall have the meaning as set forth and defined in individual award agreements. Notwithstanding the foregoing, if a Change in Control constitutes a payment event with respect to any Award which provides for the deferral of compensation and is subject to Section 409A, the transaction or event with respect to such Award must also constitute a “change in control event,” as defined in Treasury Regulation §1.409A-3(i)(5), and as relates to the holder of such Award, to the extent required to comply with Section 409A.

“ Code ” means the Internal Revenue Code of 1986, as amended.

“ Commission ” means the United States Securities and Exchange Commission or any successor organization.

“ Committee ” means the Board, except that it shall mean such committee or sub-committee of the Board as may be appointed by the Board to administer the Plan, or as necessary to comply with applicable legal requirements or listing standards.

“ Director ” means a member of the board of directors or board of managers, as the case may be, of the Company, the Partnership or any of their Affiliates who is not an Employee or Officer, provided that such person is eligible to receive Awards that may be registered under a Registration Statement on Form S-8 (or any successor form) in accordance with applicable Commission or other rules or regulations.

“ Disability ” means either (a) a condition that renders the Participant wholly and continuously disabled for a period of at least two years, to the extent that the Participant is unable to engage in any occupation or perform any work for gainful compensation or profit for which he or she is, or may become, reasonably qualified by education, training or experience; or (b) a condition for which the Participant has obtained a Social Security Administration determination of disability. If a Disability constitutes a payment event with respect to any Award which provides for the deferral of compensation and is subject to Section 409A, then, to the extent required to comply with Section 409A, the Participant must also be considered “disabled” within the meaning of Section 409A(a)(2)(C) of the Code.

“Distribution Equivalent Right” or “DER ” means a contingent right to receive an amount in cash at such times as set forth in an Award Agreement or as determined by the Committee, Units, Restricted Units and/or Phantom Units equal in value to the distributions made by the Partnership with respect to a Unit during the period such Award is outstanding.

“ Employee ” means an employee of the Company, the Partnership or any of their Affiliates, provided that such employee is eligible to receive Awards that may be registered under a Registration Statement on Form S-8 (or any successor form) in accordance with applicable Commission or other rules or regulations. The term Employee under this Plan may also include any other individual who may be considered an “employee” under a Registration Statement on Form S-8 (or any successor form) in accordance with applicable Commission or other rules or regulations.

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“ Exchange Act ” means the Securities Exchange Act of 1934, as amended.

“ Fair Market Value ” of a Unit means, as of a particular date: (i) if the Units are listed on a national securities exchange, the closing price per Unit on the consolidated transaction reporting system for the principal national securities exchange on which the Units are listed on that date, or, if there shall have been no such sale so reported on that date, on the next succeeding date on which such a sale is so reported, or, at the discretion of the Committee, any other reasonable and objectively determinable method based on the listed price per Unit which reflects the price prevailing on the exchange at the time of grant; (ii) if the Units are not so listed but are quoted on a national securities market, the closing sales price per Unit reported on such market for such date, or, if there shall have been no such sale so reported on that date, on the next succeeding date on which such a sale is so reported; or (iii) if the Units are not so listed or quoted, the most recent value determined by an independent appraiser appointed by the Company for such purpose. For any determination of Fair Market Value, if the commitment to measure the Fair Market Value is based on the average trading price over a specified period, such period cannot extend more than thirty (30) days before or thirty (30) days after the grant date and such commitment must be irrevocably established for specified Awards before the beginning of such period.

“ Officer ” means any individual who is appointed or elected to serve as an officer of the Company, the Partnership or any of their Affiliates, provided that such individual is eligible to receive Awards that may be registered under a Registration Statement on Form S-8 (or any successor form) in accordance with applicable Commission or other rules or regulations.

“ Option ” means an option to purchase Units granted pursuant to 6(a) of the Plan.

“ Other Unit-Based Award ” means an Award granted pursuant to 6(f) of the Plan.

“ Participant ” means an Employee, Officer or Director granted an Award under the Plan and any authorized transferee of such individual.

“ Partnership Agreement ” means the Agreement of Limited Partnership of the Partnership, as it may be amended or amended and restated from time to time.

“ Person ” shall have the meaning ascribed to such term in Section 3(a)(9) of the Exchange Act and used in Sections 13(d) and 14(d) thereof, including a “group” as defined in Section 13(d) thereof.

“ Phantom Unit ” means a notional interest granted under the Plan that, to the extent vested, entitles the Participant to receive a Unit or an amount of cash equal to the Fair Market Value of a Unit, as determined by the Committee in its discretion.

“ Plan Year ” means the calendar year.

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“ Profits Interest Unit ” means to the extent authorized by the Partnership Agreement, an interest in the Partnership that is intended to constitute a “profits interest” within the meaning of the Code, Department of Treasury Regulations promulgated thereunder and any published guidance by the Internal Revenue Service with respect thereto.

“ Recoupment Provision ” means any clawback or recovery provision required by applicable law including United States federal and state securities laws or by any national securities exchange on which the Units of the Partnership are listed or any applicable regulatory requirement, or as set forth in any individual Award Agreement under the Plan.

“ Restricted Period ” means the period established by the Committee with respect to an Award during which the Award remains subject to forfeiture and is either not exercisable by or payable to the Participant, as the case may be.

“ Restricted Unit ” means a Unit granted pursuant to 6(b) of the Plan that is subject to a Restricted Period.

“ Retirement ” means termination of employment of an Employee on or after the time at which the Employee either (a) is eligible for retirement under the Marathon Petroleum Retirement Plan or Speedway Retirement Plan, or a successor retirement plan of either, if the Employee is or was a participant in such plan or (b) has attained age 50 and completed ten years of employment with the Partnership, the Company or their Affiliates, as applicable. However, the term Retirement does not include an event following which the Participant remains an Employee. Notwithstanding the foregoing, the term “Retirement” if separately defined in an individual Award Agreement, shall have the meaning as set forth in any such individual Award Agreement.

“ Securities Act ” means the Securities Act of 1933, as amended.

“ SEC ” means the Securities and Exchange Commission, or any successor thereto.

“ Section 409A ” means Section 409A of the Code and the Department of Treasury Regulations and other interpretive guidance issued thereunder, including without limitation any such regulations or other guidance that may be issued after the Effective Date (as defined in 9 below).

“ Service ” means service as an Employee, Officer or Director. The Committee, in its sole discretion, shall determine the effect of all matters and questions relating to terminations of Service, including, without limitation, the questions of whether and when a termination of Service occurred and/or resulted from a discharge for Cause, and all questions of whether particular changes in status or leaves of absence constitute a termination of Service. The Committee, in its sole discretion, subject to the terms of any applicable Award Agreement, may determine that a termination of Service has not occurred in the event of (a) a termination where there is simultaneous commencement by the Participant of a relationship with the Partnership, the Company or any of their Affiliates as an Employee, Officer or Director or (b) a termination which results in a temporary severance of the Service relationship.

“ Substitute Award ” means an Award granted pursuant to 6(g) of the Plan.

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“ Unit ” means a common unit of the Partnership.

“ Unit Appreciation Right ” or “ UAR ” means a contingent right that entitles the holder to receive the excess of the Fair Market Value of a Unit on the exercise date of the UAR over the exercise price of the UAR. Such excess value may take the form of Units or cash as determined by the Committee.

“ Unit Award ” means an Award granted pursuant to 6(d) of the Plan.

3. Administration .

(a) The Plan shall be administered by the Committee, subject to subsection (b) below; provided, however, that in the event that the Board is not also serving as the Committee, the Board, in its sole discretion, may at any time and from time to time exercise any and all rights and duties of the Committee under the Plan. The governance of the Committee shall be subject to the charter, if any, of the Committee as approved by the Board. Subject to the terms of the Plan and applicable law, and in addition to other express powers and authorizations conferred on the Committee by the Plan, the Committee shall have full power and authority to: (i) designate Participants; (ii) determine the type or types of Awards to be granted to a Participant; (iii) determine the number of Units to be covered by Awards; (iv) determine the terms and conditions of any Award; (v) determine whether, to what extent, and under what circumstances Awards may be settled, exercised, canceled or forfeited; (vi) interpret and administer the Plan and any instrument or agreement relating to an Award made under the Plan; (vii) establish, amend, suspend or waive such rules and regulations and appoint such agents as it shall deem appropriate for the proper administration of the Plan; and (viii) make any other determination and take any other action that the Committee deems necessary or desirable for the administration of the Plan. The Committee may correct any defect or supply any omission or reconcile any inconsistency in the Plan or an Award Agreement in such manner and to such extent as the Committee deems necessary or appropriate. Unless otherwise expressly provided in the Plan, all designations, determinations, interpretations and other decisions under or with respect to the Plan or any Award shall be within the sole discretion of the Committee, may be made at any time, and shall be final, conclusive and binding upon all Persons, including the Company, the Partnership, any of their Affiliates, any Participant and any beneficiary of any Participant.

(b) To the extent permitted by applicable law and the rules of any securities exchange on which the Units are listed, quoted or traded, the Board or Committee may from time to time delegate to a committee of one or more members of the Board or one or more Officers the authority to grant or amend Awards or to take other administrative actions pursuant to 3(a); provided, however, that in no event shall an Officer be delegated the authority to grant Awards to, or amend Awards held by, the following individuals: (i) individuals who are subject to Section 16 of the Exchange Act, or (ii) Officers (or Directors) to whom authority to grant or amend Awards has been delegated hereunder; provided, further, that any delegation of administrative authority shall only be permitted to the extent that it is permissible under applicable provisions of the Code and applicable securities laws and the rules of any securities exchange on which the Units are listed, quoted or traded. Any delegation hereunder shall be subject to such restrictions and limitations as the Board or Committee, as applicable, specifies at the time of such delegation, and the Board or Committee, as applicable, may at any time rescind the authority so delegated or appoint a new delegate. At all times, the delegate appointed under this 3(b) shall serve in such capacity at the pleasure of the Board and the Committee.

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4. Units Available for Awards .

(a) Limits on Units Deliverable . Subject to adjustment as provided in 4(c), the number of Units that will be available to be delivered with respect to Awards under the Plan is 2,750,000 common units. If any Award is forfeited, canceled, exercised, paid or otherwise terminates or expires without the actual delivery of Units pursuant to such Award (for the avoidance of doubt, the grant of Restricted Units is not a delivery of Units for this purpose unless and until such Restricted Units vest and any restrictions placed upon them under the Plan lapse), the Units subject to such Award shall again be available for Awards under the Plan. To the extent permitted by applicable law and securities exchange rules, Substitute Awards and Units issued in assumption of, or in substitution for, any outstanding awards of any entity acquired in any form of combination by the Partnership or any Affiliate thereof shall not be counted against the Units available for issuance pursuant to the Plan. There shall not be any limitation on the number of Awards that may be paid in cash. Awards that by their terms do not permit settlement in Units shall not reduce the number of Units available for issuance pursuant to the Plan.

(b) Sources of Units Deliverable Under Awards . Any Units delivered pursuant to an Award shall consist, in whole or in part, of Units acquired in the open market, from the Partnership, any Affiliate thereof or any other Person, or Units otherwise issuable by the Partnership, or any combination of the foregoing, as determined by the Committee in its discretion.

(i) Equity Restructuring . With respect to any “equity restructuring” event that could result in an additional compensation expense to the Company or the Partnership pursuant to the provisions of ASC Topic 718 if adjustments to Awards with respect to such event were discretionary, the Committee shall equitably adjust the number and type of Units covered by each outstanding Award and the terms and conditions, including the exercise price and performance criteria (if any), of such Award to equitably reflect such event and shall adjust the number and type of Units (or other securities or property) with respect to which Awards may be granted under the Plan after such event. With respect to any other similar event that would not result in an ASC Topic 718 accounting charge if the adjustment to Awards with respect to such event were subject to discretionary action, the Committee shall have complete discretion to adjust Awards and the number and type of Units (or other securities or property) with respect to which Awards may be granted under the Plan in such manner as it deems appropriate with respect to such other event.

(ii) Other Changes in Capitalization . In the event of any non-cash distribution, Unit split, combination or exchange of Units, merger, consolidation or distribution (other than normal cash distributions) of Partnership assets to unitholders, or any other change affecting the Units of the Partnership, other than an “equity restructuring,” the Committee may make equitable adjustments, if any, to reflect such change with respect to (A) the aggregate number and kind of Units that may be issued under the Plan; (B) the number

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and kind of Units (or other securities or property) subject to outstanding Awards; (C) the terms and conditions of any outstanding Awards (including, without limitation, any applicable performance targets or criteria with respect thereto); and (D) the grant or exercise price per Unit for any outstanding Awards under the Plan.

5. Eligibility .

In the sole discretion of the Committee, any Employee, Officer or Director shall be eligible to be designated a Participant and receive an Award under the Plan.

6. Awards .

(a) Options and UARs . The Committee shall have the authority to determine the Employees, Officers, and Directors to whom Options and/or UARs shall be granted, the number of Units to be covered by each Option or UAR, the exercise price therefore, the Restricted Period and other conditions and limitations applicable to the exercise of the Option or UAR, including the following terms and conditions and such additional terms and conditions, as the Committee shall determine, that are not inconsistent with the provisions of the Plan. Options which are intended to comply with Treasury Regulation Section 1.409A-1(b)(5)(i)(A) and UARs which are intended to comply with Treasury Regulation Section 1.409A-1(b)(5)(i)(B) or, in each case, any successor regulation, may be granted only if the requirements of Treasury Regulation Section 1.409A-1(b)(5)(iii), or any successor regulation, are satisfied. Options and UARs that are otherwise exempt from or compliant with Section 409A may be granted to any eligible Employee, Officer or Director.

(i) Exercise Price . The exercise price per Unit purchasable under an Option or subject to a UAR shall be determined by the Committee at the time the Option or UAR is granted but, except with respect to a Substitute Award, may not be less than the Fair Market Value of a Unit as of the date of grant of the Option or UAR.

(ii) Time and Method of Exercise . The Committee shall determine the exercise terms and any applicable Restricted Period with respect to an Option or UAR, which may include, without limitation, provisions for accelerated vesting upon the achievement of specified performance goals and/or other events, and the method or methods by which payment of the exercise price with respect to an Option or UAR may be made or deemed to have been made, which may include, without limitation, cash, check acceptable to the Company, withholding Units having a Fair Market Value on the exercise date equal to the relevant exercise price from the Award, a “cashless” exercise or a “net exercise” through procedures approved by the Company, or any combination of the foregoing methods.

(iii) Exercise of Options and UARs on Termination of Service . Each Option and UAR Award Agreement shall set forth the extent to which the Participant shall have the right to exercise the Option or UAR following a termination of the Participant’s Service. Unless otherwise determined by the Committee, if the Participant’s Service is terminated for Cause, the Participant’s right to exercise the Option or UAR shall terminate as of the start of business on the effective date of the Participant’s termination.

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Unless otherwise determined by the Committee, to the extent the Option or UAR is not vested and exercisable as of the termination of Service, the Option or UAR shall terminate when the Participant’s Service terminates.

(iv) Term of Options and UARs . The term of each Option and UAR shall be stated in the Award Agreement, provided , that the term shall be no more than ten (10) years from the date of grant thereof.

(b) Restricted Units and Phantom Units . The Committee shall have the authority to determine the Employees, Officers and Directors to whom Restricted Units and/or Phantom Units shall be granted, the number of Restricted Units or Phantom Units to be granted to each such Participant, the applicable Restricted Period, the conditions under which the Restricted Units or Phantom Units may become vested or forfeited and such other terms and conditions, including, without limitation, restrictions on transferability, as the Committee may establish with respect to such Awards.

(i) Payment of Phantom Units . The Committee shall specify in an Award Agreement, or permit the Participant to elect in accordance with the requirements of Section 409A, the conditions and dates or events upon which the cash or Units underlying an Award of Phantom Units shall be issued, which dates or events shall not be earlier than the date on which the Phantom Units vest and become non-forfeitable and which conditions and dates or events shall be subject to compliance with Section 409A (unless the Phantom Units are exempt therefrom).

(ii) Vesting of Restricted Units . Upon or as soon as reasonably practicable following the vesting of each Restricted Unit, subject to satisfying the tax withholding obligations of 8(b), the Participant shall be entitled to have the restrictions removed from his or her Unit certificate (or book-entry account, as applicable) so that the Participant then holds an unrestricted Unit.

(c) DERs . The Committee shall have the authority to determine the Employees, Officers and/or Directors to whom DERs are granted, whether such DERs are in tandem with other Awards or constitute separate Awards, whether the DERs shall be paid directly to the Participant, be credited to a bookkeeping account (with or without interest in the discretion of the Committee), any vesting restrictions and payment provisions applicable to the DERs, and such other provisions or restrictions as determined by the Committee in its discretion, all of which shall be specified in the applicable Award Agreements. Distributions in respect of DERs shall be credited as of the distribution dates during the period between the date an Award is granted to a Participant and the date such Award vests, is exercised, is distributed or expires, as determined by the Committee. Such DERs shall be converted to cash, Units, Restricted Units and/or Phantom Units by such formula and at such time and subject to such limitations as may be determined by the Committee. Tandem DERs may be subject to the same or different vesting restrictions as the tandem Award, or be subject to such other provisions or restrictions as determined by the Committee in its discretion. Notwithstanding the foregoing, DERs shall only be paid in a manner that is either exempt from or in compliance with Section 409A.

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(d) Unit Awards . Awards of Units may be granted under the Plan (i) to such Employees, Officers and/or Directors and in such amounts as the Committee, in its discretion, may select, and (ii) subject to such other terms and conditions, including, without limitation, restrictions on transferability, as the Committee may establish with respect to such Awards.

(e) Profits Interest Units . Any Award consisting of Profits Interest Units may be granted to an Employee, Officer or Director for the performance of services to or for the benefit of the Partnership (i) in the Participant’s capacity as a partner of the Partnership, (ii) in anticipation of the Participant becoming a partner of the Partnership, or (iii) as otherwise determined by the Committee. At the time of grant, the Committee shall specify the date or dates on which the Profits Interest Units shall vest and become non-forfeitable, and may specify such conditions to vesting as it deems appropriate. Profits Interest Units shall be subject to such restrictions on transferability and other restrictions as the Committee may impose.

(f) Other Unit-Based Awards/Performance Units . Other Unit-Based Awards may be granted under the Plan to such Employees, Officers and/or Directors as the Committee, in its discretion, may select. An Other Unit-Based Award shall be an Award denominated or payable in, valued in or otherwise based on or related to Units, in whole or in part. The Committee shall determine the terms and conditions of any Other Unit-Based Award. Upon vesting, an Other Unit-Based Award may be paid in cash, Units (including Restricted Units) or any combination thereof as provided in the Award Agreement. Without limiting the type or number of Other Unit-Based Awards that may be made under the Plan, any Other Unit-Based Award may be in the form of an Other Unit-Based Award which vests based on performance criteria selected by the Committee (“Performance Units”). Any Award which vests based on performance criteria shall have a minimum performance period of one year from the grant date, provided that the Committee (or its delagate) may provide for earlier vesting following a Change in Control or other specified events involving the Company, or upon a termination of employment by reason of death, Disability or Retirement. Additionally, Employees who are Officers at the time a performance vested Award is made that will settle in full-value Units may be subject to an additional holding period after the performance period ends. The Committee shall set performance criteria in its sole discretion which, depending on the extent to which they are met, may determine the value and/or amount of such performance vested Awards that will be paid out to the Participant and/or the portion of a performance vested Award that may be exercised. Further, the Committee shall have the discretion to adjust the performance goals (either up or down) as well as the level of the performance vested Award that a Participant may earn if it determines that the occurrence of external changes or other unanticipated business conditions have materially affected the fairness of the goals and/or have unduly influenced the Company’s ability to meet them, including without limitation, events such as material acquisitions, force majeure events, unlawful acts committed against the Company or its property, labor disputes, legal mandates, asset write-downs, litigation, claims, judgments or settlements, the effect of changes in tax law or other such laws or provisions affecting reported results, accruals for reorganization and restructuring programs, changes in the capital structure of the Company and extraordinary accounting changes. In addition, performance goals and performance vested Awards shall be calculated without regard to any changes in accounting standards or codifications that may be required by the Financial Accounting Standards Board (or any successor organization) after such performance goals are established.

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(g) Substitute Awards . Awards may be granted under the Plan in substitution of similar awards held by individuals who become Employees, Officers or Directors as a result of a merger, consolidation or acquisition by the Partnership or an Affiliate of another entity or the assets of another entity. Such Substitute Awards that are Options or UARs may have exercise prices less than the Fair Market Value of a Unit on the date of the substitution if such substitution complies with Section 409A and other applicable laws and securities exchange rules.

(h) General .

(i) Award Agreements . Each Award shall be evidenced in either an individual Award Agreement or within a separate plan, policy, agreement or other written document, which shall reflect any vesting conditions or restrictions imposed by the Committee covering a period of time specified by the Committee and shall also contain such terms, conditions and limitations as shall be determined by the Committee in its sole discretion, including but not limited to applicable Recoupment Provisions. Where signature or electronic acceptance of the Award Agreement by the Participant is required, any such Awards for which the Award Agreement is not signed or electronically accepted within 11 months of the grant date shall be forfeited.

(ii) Forfeitures . Except as otherwise provided in the terms of an Award Agreement, upon termination of a Participant’s Service for any reason during an applicable Restricted Period, all outstanding, unvested Awards held by such Participant shall be automatically forfeited by the Participant. The Committee may, in its discretion, waive in whole or in part such forfeiture with respect to any such Award; provided , that any such waiver shall be effective only to the extent that such waiver will not cause any Award intended to satisfy the requirements of Section 409A to fail to satisfy such requirements.

(iii) Awards May Be Granted Separately or Together . Awards may, in the discretion of the Committee, be granted either alone or in addition to, in tandem with, or in substitution for any other Award granted under the Plan or any award granted under any other plan of the Company or any Affiliate. Awards granted in addition to or in tandem with other Awards or awards granted under any other plan of the Company or any Affiliate may be granted either at the same time as or at a different time from the grant of such other Awards or awards.

(iv) Director Awards . The Committee may, in its discretion, provide that Awards granted to Directors shall be granted pursuant to a non-discretionary formula established by the Committee by resolution, subject to the limitations of the Plan. Any such resolution shall set forth the type of Awards to be granted to Directors, the number of Units to be subject to Director Awards, the conditions on which such Awards shall be granted, vest, become exercisable and/or payable and expire, and such other terms and conditions as the Committee shall determine in its discretion. The Committee may also establish a written policy for grants to Directors which shall set forth the type and terms of Awards granted to Directors and such policy may be modified by the Committee from time to time in its discretion.

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(v) Limits on Transfer of Awards .

(A) Except as provided in paragraph (C) below, each Option and UAR shall be exercisable only by the Participant during the Participant’s lifetime, or by the Person to whom the Participant’s rights shall pass by will or the laws of descent and distribution.

(B) Except as provided in paragraph (C) below, no Award and no right under any such Award may be assigned, alienated, pledged, attached, sold or otherwise transferred or encumbered by a Participant other than by will or the laws of descent and distribution and any such purported assignment, alienation, pledge, attachment, sale, transfer or encumbrance shall be void and unenforceable against the Company, the Partnership or any Affiliate.

(C) The Committee may provide in an Award Agreement that an Award may, on such terms and conditions as the Committee may from time to time establish, be transferred by a Participant without consideration to any “family member” of the Participant, as defined in the instructions for use of the Registration Statement on Form S-8 (or any successor form) under the Securities Act, as applicable, or any other transferee specifically approved by the Committee after taking into account any state, federal, local or foreign tax and securities laws applicable to transferable Awards. In addition, vested Units may be transferred to the extent permitted by the Partnership Agreement and not otherwise prohibited by the Award Agreement or any other agreement restricting the transfer of such Units.

(vi) Term of Awards . Subject to 6(a)(iv) above, the term of each Award, if any, shall be for such period as may be determined by the Committee.

(vii) Unit Certificates . Unless otherwise determined by the Committee or required by any applicable law, rule or regulation, neither the Company nor the Partnership shall deliver to any Participant certificates evidencing Units issued in connection with any Award and instead such Units shall be recorded in the books of the Partnership (or, as applicable, its transfer agent or equity plan administrator). All certificates for Units or other securities of the Partnership delivered under the Plan and all Units issued pursuant to book entry procedures pursuant to any Award or the exercise thereof shall be subject to such stop-transfer orders and other restrictions as the Committee may deem advisable under the Plan or the rules, regulations and/or other requirements of the SEC, any securities exchange upon which such Units or other securities are then listed, and any applicable federal or state laws, and the Committee may cause a legend or legends to be inscribed on any such certificates or book entry to make appropriate reference to such restrictions.

(viii) Consideration for Grants . To the extent permitted by applicable law, Awards may be granted for such consideration, including services, as the Committee shall determine.

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(ix) Delivery of Units or other Securities and Payment by Participant of Consideration . Notwithstanding anything in the Plan or any Award Agreement to the contrary, subject to compliance with Section 409A, the Company shall not be required to issue or deliver any certificates or make any book entries evidencing Units pursuant to the exercise or vesting of any Award, unless and until the Board or the Committee has determined, with advice of counsel, that the issuance of such Units is in compliance with all applicable laws, regulations of governmental authorities and, if applicable, the requirements of any securities exchange on which the Units are listed or traded, and the Units are covered by an effective registration statement or applicable exemption from registration. In addition to the terms and conditions provided herein, the Board or the Committee may require that a Participant make such reasonable covenants, agreements and representations as the Board or the Committee, in its discretion, deems advisable in order to comply with any such laws, regulations or requirements. Without limiting the generality of the foregoing, the delivery of Units pursuant to the exercise or vesting of an Award may be deferred for any period during which, in the good faith determination of the Committee, the Company is not reasonably able to obtain or deliver Units pursuant to such Award without violating applicable law or the applicable rules or regulations of any governmental agency or authority or securities exchange. No Units or other securities shall be delivered pursuant to any Award until payment in full of any amount required to be paid pursuant to the Plan or the applicable Award Agreement (including, without limitation, any exercise price or tax withholding) is received by the Company.

7. Amendment and Termination; Certain Transactions .

Except as required by applicable law or the rules of the principal securities exchange, if any, on which the Units are traded:

(a) Amendments to the Plan . Subject to 7(b) below, the Board or the Committee may amend, alter, suspend, discontinue or terminate the Plan in any manner without the consent of any partner, Participant, other holder or beneficiary of an Award, or any other Person. The Board shall obtain unitholder approval of any Plan amendment to the extent necessary to comply with applicable law or securities exchange listing standards or rules.

(b) Amendments to Awards . Subject to 7(a) above, the Committee may waive any conditions or rights under, amend any terms of, or alter any Award theretofore granted, provided that no change, other than pursuant to 7(c) below, in any Award shall materially reduce the rights or benefits of a Participant with respect to an Award without the consent of such Participant. No Option Award may be repriced, replaced, regranted through cancellation or modified without approval of the unitholders of the Partnership (except as contemplated in 7(c) below), if the effect would be to reduce the exercise price for the Units underlying such Award.

(c) Actions Upon the Occurrence of Certain Events . Upon the occurrence of a Change in Control, any transaction or event described in 4(c) above, any change in applicable laws or regulations affecting the Plan or Awards hereunder, or any change in accounting principles affecting the financial statements of the Company or the Partnership, the Committee, in its sole discretion, without the consent of any Participant or holder of an Award, and on such terms and conditions as it deems appropriate, may take any one or more of the following actions:

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(i) provide for either (A) the termination of any Award in exchange for a payment in an amount, if any, equal to the amount that would have been attained upon the exercise of such Award or realization of the Participant’s rights under such Award (and, for the avoidance of doubt, if as of the date of the occurrence of such transaction or event, the Committee determines in good faith that no amount would have been payable upon the exercise of such Award or realization of the Participant’s rights, then such Award may be terminated by the Company without payment) or (B) the replacement of such Award with other rights or property selected by the Committee in its sole discretion having an aggregate value not exceeding the amount that could have been attained upon the exercise of such Award or realization of the Participant’s rights had such Award been currently exercisable or payable or fully vested;

(ii) provide that such Award be assumed by the successor or survivor entity, or a parent or subsidiary thereof, or be exchanged for similar options, rights or awards covering the equity of the successor or survivor, or a parent or subsidiary thereof, with appropriate adjustments as to the number and kind of equity interests and prices;

(iii) make adjustments in the number and type of Units (or other securities or property) subject to outstanding Awards, the number and kind of outstanding Awards, the terms and conditions of (including the exercise price) and/or the vesting and performance criteria included in, outstanding Awards;

(iv) provide that such Award shall vest or become exercisable or payable, notwithstanding anything to the contrary in the Plan or the applicable Award Agreement; and

(v) provide that the Award cannot be exercised or become payable after such event and shall terminate upon such event and may also provide, in the Committee’s sole discretion, to pay or substitute the full value of such Award.

(d) Notwithstanding the foregoing, (i) with respect to an above event that constitutes an “equity restructuring” that would be subject to a compensation expense pursuant to ASC Topic 718, the provisions in 4(c) above shall control to the extent they are in conflict with the discretionary provisions of this 7, provided, however , that nothing in 7(c) or 4(c) above shall be construed as providing any Participant or any beneficiary of an Award any rights with respect to the “time value,” “economic opportunity” or “intrinsic value” of an Award or limiting in any manner the Committee’s actions that may be taken with respect to an Award as set forth in this 7 or in 4(c) above; and (ii) no action shall be taken under this 7 which shall cause an Award to result in taxation under Section 409A, to the extent applicable to such Award.

8. General Provisions .

(a) No Rights to Award . No Person shall have any claim to be granted any Award under the Plan, and there is no obligation for uniformity of treatment of Participants, including the treatment upon termination of Service. The terms and conditions of Awards need not be the same with respect to each recipient.

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(b) Tax Withholding . Unless other arrangements have been made that are acceptable to the Company, the Company or any Affiliate thereof is authorized to deduct or withhold, or cause to be deducted or withheld, from any Award, from any payment due or transfer made under any Award, or from any compensation or other amount owing to a Participant the amount (in cash or Units, including Units that would otherwise be issued pursuant to such Award or other property) of any applicable taxes payable in respect of an Award, including its grant, its exercise, the lapse of restrictions thereon or any payment or transfer thereunder or under the Plan, and to take such other action as may be necessary in the opinion of the Company to satisfy its withholding obligations for the payment of such taxes. In the event that Units that would otherwise be issued pursuant to an Award are used to satisfy such withholding obligations, the number of Units which may be so withheld or surrendered shall be limited to the number of Units which have a Fair Market Value on the date of withholding equal to the aggregate amount of such liabilities based on the minimum statutory withholding rates for federal, state, local and foreign income tax and payroll tax purposes that are applicable to such supplemental taxable income.

(c) No Right to Employment or Services . The grant of an Award shall not be construed as giving a Participant the right to be retained in the employ of the Company, the Partnership or any of their Affiliates, or to remain on the Board, as applicable. Furthermore, the Company, the Partnership and/or an Affiliate thereof may at any time dismiss a Participant from employment free from any liability or any claim under the Plan, unless otherwise expressly provided in the Plan, any Award Agreement or other written agreement between any such entity and the Participant.

(d) Limitation of Liability . No member of the Board or the Committee or Officer to whom the Board or the Committee has delegated authority in accordance with the provisions of 3 of this Plan shall be liable for anything done or omitted to be done by him or her by any member of the Board or the Committee or by any Officer in connection with the performance of any duties under this Plan, except for his or her own willful misconduct or as expressly provided by statute.

(e) No Rights as Unitholder . Except as otherwise provided herein, a Participant shall have none of the rights of a unitholder with respect to Units covered by any Award unless and until the Participant becomes the record owner of such Units.

(f) Section 409A . To the extent that the Committee determines that any Award granted under the Plan is subject to Section 409A, the Award Agreement evidencing such Award shall include the terms and conditions required by Section 409A. To the extent applicable, the Plan and Award Agreements shall be interpreted in accordance with Section 409A. Notwithstanding any provision of the Plan to the contrary, in the event that following the Effective Date (as defined in 9 below), the Committee determines that any Award may be subject to Section 409A, the Committee may adopt such amendments to the Plan and the applicable Award Agreement, adopt other policies and procedures (including amendments, policies and procedures with retroactive effect) and/or take any other actions that the Committee determines are necessary or appropriate to preserve the intended tax treatment of the Award, including without limitation, actions intended to (i) exempt the Award from Section 409A, or (ii) comply with the requirements of Section 409A; provided, however, that nothing herein shall create any

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obligation on the part of the Committee, the Partnership, the Company or any of their Affiliates to adopt any such amendment, policy or procedure or take any such other action, nor shall the Committee, the Partnership, the Company or any of their Affiliates have any liability for failing to do so. Notwithstanding any provision in the Plan to the contrary, the time of payment with respect to any Award that is subject to Section 409A shall not be accelerated, except as permitted under Treasury Regulation Section 1.409A-3(j)(4). Notwithstanding any provision of this Plan to the contrary, if a Participant is a “Specified Employee” within the meaning of Section 409A as of the date of such Participant’s termination of employment and the Company determines, in good faith, that immediate payment of any amounts or benefits under this Plan would cause a violation of Section 409A, then any amounts or benefits which are payable under this Plan upon the Participant’s “separation from service” within the meaning of Section 409A that: (i) are subject to the provisions of Section 409A; (ii) are not otherwise exempt under Section 409A; and (iii) would otherwise be payable during the first six-month period following such separation from service, shall be paid as soon as practicable on the first business day next following the earlier of: (1) the date that is six months and one day following the date of termination; or (2) the date of the Participant’s death.

(g) Lock-Up Agreement . Each Participant shall agree, if so requested by the Company or the Partnership and any underwriter in connection with any public offering of securities of the Partnership or any Affiliate, not to directly or indirectly offer, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant for the sale of or otherwise dispose of or transfer any Units held by it for such period, not to exceed one hundred eighty (180) days following the effective date of the relevant registration statement filed under the Securities Act in connection with such public offering, as such underwriter shall specify reasonably and in good faith. The Company or the Partnership may impose stop-transfer instructions with respect to securities subject to the foregoing restrictions until the end of such 180-day period. Notwithstanding the foregoing, the 180-day period may be extended for up to such number of additional days as is deemed necessary by such underwriter or the Company or Partnership to continue coverage by research analysts in accordance with FINRA Rule 2711 or any successor rule.

(h) Compliance with Laws . The Plan, the granting and vesting of Awards under the Plan and the issuance and delivery of Units and the payment of money under the Plan or under Awards granted or awarded hereunder are subject to compliance with all applicable federal, state, local and foreign laws, rules and regulations (including but not limited to state, federal and foreign securities law and margin requirements), the rules of any securities exchange or automated quotation system on which the Units are listed, quoted or traded, and to such approvals by any listing, regulatory or governmental authority as may, in the opinion of counsel for the Company or the Partnership, be necessary or advisable in connection therewith. Any securities delivered under the Plan shall be subject to such restrictions, and the Person acquiring such securities shall, if requested by the Company or the Partnership, provide such assurances and representations to the Company or the Partnership as the Company or the Partnership may deem necessary or desirable to assure compliance with all applicable legal requirements. To the extent permitted by applicable law, the Plan and Awards granted or awarded hereunder shall be deemed amended to the extent necessary to conform to such laws, rules and regulations. In the event an Award is granted to or held by a Participant who is employed or providing services outside the United States, the Committee may, in its sole discretion, modify the provisions of the

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Plan or of such Award as they pertain to such Participant to comply with applicable foreign law or to recognize differences in local law, currency or tax policy. The Committee may also impose conditions on the grant, issuance, exercise, vesting, settlement or retention of Awards in order to comply with such foreign law and/or to minimize the Company’s or the Partnership’s obligations with respect to tax equalization for Participants employed outside their home country.

(i) Governing Law . The validity, construction and effect of the Plan and any rules and regulations relating to the Plan shall be determined in accordance with the laws of the State of Delaware without regard to its conflicts of laws principles.

(j) Severability . If any provision of the Plan or any Award is or becomes, or is deemed to be, invalid, illegal or unenforceable in any jurisdiction or as to any Person or Award, or would disqualify the Plan or any Award under any law deemed applicable by the Committee, such provision shall be construed or deemed amended to conform to the applicable law or, if it cannot be construed or deemed amended without, in the determination of the Committee, materially altering the intent of the Plan or the Award, such provision shall be stricken as to such jurisdiction, Person or Award and the remainder of the Plan and any such Award shall remain in full force and effect.

(k) Other Laws . The Committee may refuse to issue or transfer any Units or other consideration under an Award if, in its sole discretion, it determines that the issuance or transfer of such Units or such other consideration might violate any applicable law or regulation, the rules of the principal securities exchange on which the Units are then traded, or entitle the Partnership or an Affiliate to recover the same under Section 16(b) of the Exchange Act, and any payment tendered to the Company by a Participant, other holder or beneficiary in connection with the exercise of such Award shall be promptly refunded to the relevant Participant, holder or beneficiary.

(l) No Trust or Fund Created . Neither the Plan nor any Award shall create or be construed to create a trust or separate fund of any kind or a fiduciary relationship between the Company, the Partnership or any of their Affiliates, on the one hand, and a Participant or any other Person, on the other hand. To the extent that any Person acquires a right to receive payments pursuant to an Award, such right shall be no greater than the right of any general unsecured creditor of the Partnership or any participating Affiliate of the Partnership.

(m) No Fractional Units . No fractional Units shall be issued or delivered pursuant to the Plan or any Award, and the Committee shall determine whether cash, other securities or other property shall be paid or transferred in lieu of any fractional Units or whether such fractional Units or any rights thereto shall be canceled, terminated or otherwise eliminated.

(n) Headings . Headings are given to the sections and subsections of the Plan solely as a convenience to facilitate reference. Such headings shall not be deemed in any way material or relevant to the construction or interpretation of the Plan or any provision hereof.

(o) No Guarantee of Tax Consequences . None of the Board, the Committee, the Company or the Partnership provides or has provided any tax advice to any Participant or any other Person or makes or has made any assurance, commitment or guarantee that any federal, state or local tax treatment will (or will not) apply or be available to any Participant or other Person.

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(p) Non-United States Participants . The Board or Committee may grant Awards to persons outside the United States under such terms and conditions as may, in the judgment of the Board or Committee, as applicable, be necessary or advisable to comply with the laws of the applicable foreign jurisdictions and, to that end, may establish sub-plans, modified vesting, exercise or settlement procedures and other terms and procedures. Notwithstanding the above, neither the Board nor the Committee may take any actions under this Plan, and no Awards shall be granted, that would violate the Exchange Act, the Code or any other applicable law.

(q) Facility Payment . Any amounts payable hereunder to any Person under legal disability or who, in the judgment of the Committee, is unable to manage properly his or her financial affairs, may be paid to the legal representative of such Person, or may be applied for the benefit of such Person in any manner that the Committee may select, and the Partnership, the Company and all of their Affiliates shall be relieved of any further liability for payment of such amounts.

9. Term of the Plan .

The Plan shall be effective on the date on which the Plan is adopted by the Board (the “Effective Date”) and shall continue until terminated by the Board. However, any Award granted prior to such termination, and the authority of the Board or the Committee to amend, alter, adjust, suspend, discontinue or terminate any such Award or to waive any conditions or rights under such Award, shall extend beyond such termination date.

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EXHIBIT C

MPLX LP
2012 INCENTIVE COMPENSATION PLAN

PHANTOM UNIT AWARD AGREEMENT

OFFICER – SEVERANCE

As evidenced by this Award Agreement and under the MPLX LP 2012 Incentive Compensation Plan (the “Plan”), MPLX GP LLC, a Delaware limited liability company (the “Company”), the general partner of MPLX LP, a Delaware limited partnership (the “Partnership”) has granted to [NAME] (the “Participant”), an officer of the Company, on [DATE] (the “Grant Date”), [NUMBER] Phantom Units, with each Phantom Unit representing the right to receive a Unit of the Partnership, subject to the terms and conditions in the Plan and this Award Agreement. The number of Phantom Units awarded is subject to adjustment as provided in the Plan, and the Phantom Units hereby granted are also subject to the following terms and conditions:

1. Relationship to the Plan. This grant of Phantom Units is subject to all of the terms, conditions and provisions of the Plan and administrative interpretations thereunder, if any, that have been adopted by the Board. Except as defined in this Award Agreement, capitalized terms shall have the same meanings given to them under the Plan. To the extent that any provision of this Award Agreement conflicts with the express terms of the Plan, the terms of the Plan shall control and, if necessary, the applicable provisions of this Award Agreement shall be hereby deemed amended so as to carry out the purpose and intent of the Plan.

2. Vesting and Forfeiture of Phantom Units. The Phantom Units shall vest in full upon Participant’s separation from service (as defined in Section 409A of the Code), except if Participant’s Employment is terminated for Cause (as such term is defined in Participant’s Retention Agreement with Marathon Petroleum Company LP). If Participant’s Employment is terminated for Cause (as such term is defined in Participant’s Retention Agreement with Marathon Petroleum Company LP), the Phantom Units that have not vested as of the date of such termination for Cause shall be immediately and 100% forfeited to the Company.

3. Dividends and Cash Distributions. During the period of time between the Grant Date and the date the Phantom Units are settled, for any dividends and/or cash distributions from the Partnership on outstanding Units of the Partnership, the Participant shall be credited with the equivalent of all of the dividends and/or cash distributions that would be payable with respect to the Unit of the Partnership represented by each Phantom Unit, including any fractional Phantom Units, then credited to the Participant and the amount related to such credited dividends and/or cash distributions shall be accrued as a credit to the Participant’s account on the date such dividend and/or cash distribution is made. Any additional cash or Phantom Units granted pursuant to this Paragraph 3 shall be subject to the same terms and conditions applicable to the Phantom Units to which these dividend and/or cash distributions relate, including, without limitation, the restrictions on transfer, forfeiture, settlement and distribution provisions contained in this Award Agreement or the Plan.

settle, the Phantom Units will be evidenced by a credit to a bookkeeping account evidencing the unfunded and unsecured right of the Participant to receive Units, subject to the terms and conditions applicable to the Phantom Units. Following vesting and upon the settlement date as described above, the Participant shall be entitled to receive a number of Units of the Partnership equal to the total of the number of Phantom Units granted, with any fractional Phantom Units remaining settled in cash. Such Units shall be issued and registered in the name of the Participant. The Participant shall not have the right or be entitled to exercise any voting rights, receive cash distributions or dividends or have or be entitled to any rights as a Partnership unitholder in respect of the Phantom Units until such time as the Phantom Units have vested and been settled and corresponding Units of the Partnership have been issued.

5. Taxes. Pursuant to the applicable provisions of the Plan, the Company or its designated representative shall have the right to withhold applicable taxes from the Units otherwise deliverable to the Participant due to the vesting of Phantom Units pursuant to Paragraph 2, or from other compensation payable to the Participant, at the time of the vesting and delivery of such Units. Because the Participant is an employee of Marathon Petroleum Corporation, the parent corporation of the Company (“MPC”), and provides beneficial services to the Company through Participant’s Employment with MPC, MPC as the employer of Participant shall be the designated representative for purposes of payroll administration of the Award and withholding of applicable taxes at the time of vesting.

6. Forfeiture or Repayment Resulting from Forfeiture Event.

(a) If there is a Forfeiture Event either during the Participant’s Employment or within two years after termination of the Participant’s Employment, then the Board may, but is not obligated to, cause all of the Participant’s unvested Phantom Units to be forfeited by the Participant and returned to the Company.

(b) If there is a Forfeiture Event either during the Participant’s Employment or within two years after termination of the Participant’s Employment, then with respect to Phantom Units granted under this Award Agreement that have vested, the Board may, but is not obligated to, require that the Participant pay to the Company an amount (the “Forfeiture Amount”) up to (but not in excess of) the lesser of (i) the value of such previously vested Phantom Units as of the date such Phantom Units vested or (ii) the value of such previously vested Phantom Units as of the date on which the Board makes a demand for payment of the Forfeiture Amount. Any Forfeiture Amount shall be paid by the Participant within sixty (60) days of receipt from the Company of written notice requiring payment of such Forfeiture Amount.

(c) This Paragraph 6 shall apply notwithstanding any provision of this Award Agreement to the contrary and is meant to provide the Company with rights in addition to any other remedy which may exist in law or in equity. This Paragraph 6 shall not apply to the Participant following the effective time of a Change in Control.

(d) Notwithstanding the any other provision of this Award Agreement to the contrary, the Participant agrees that the Company may also require that the Participant repay to the Company any compensation paid to the Participant under this Award Agreement, as is required by the provisions of the Dodd-Frank Wall Street Reform and Consumer Protection Act and the regulations thereunder or any other “clawback” provisions as required by law or by the applicable listing standards of the exchange on which the Units of the Partnership are listed for trading.

7. Nonassignability. Upon the Participant’s death, the Phantom Units credited to the Participant under

this Award Agreement shall be transferred to the Participant’s estate and upon such transfer settled in Units of the Partnership. Otherwise, the Participant may not sell, transfer, assign, pledge or otherwise encumber any portion of the Phantom Units, and any attempt to sell, transfer, assign, pledge or encumber any portion of the Phantom Units shall have no effect.

8. Nature of the Grant . Under this Award Agreement, the Participant is subject to the following conditions on the Award:

(a) this grant of Phantom Units is voluntary and occasional and this Award Agreement does not create any contractual or other right to receive future Awards of Phantom Units, or benefits in lieu of Phantom Units even if Phantom Units have been awarded repeatedly in the past.

9. No Employment Guaranteed. Nothing in this Award Agreement shall give the Participant any rights to (or impose any obligations for) continued Employment by the Company or any subsidiary or successor, nor shall it give such entities any rights (or impose any obligations) with respect to continued performance of duties by the Participant.

10. Modification of Instrument. Any modification of this Award Agreement shall be binding only if evidenced by resolution of the Board of the Company, provided that no modification may, without the consent of the Participant, adversely affect the rights of the Participant hereunder.

11. Section 409A. This Award is intended to comply with the requirements of Section 409A of the Code, and shall be interpreted and administered to meet the requirements of such section. If the Participant is a “specified employee” as determined by the Company in accordance with its established policy, any settlement of Phantom Units granted in this Award Agreement that would be a payment of deferred compensation within the meaning of Section 409A of the Code with respect to the Participant as a result of the Participant’s separation from service as defined under Section 409A of the Code (other than as a result of death) and which would otherwise be paid within six months of the Participant’s separation from service shall be payable on the date that is one day after the earlier of (i) the date that is six months after the Participant’s separation from service or (ii) the date that otherwise complies with the requirements of Section 409A of the Code. In addition, notwithstanding any provision of the Plan or this Award Agreement to the contrary, any settlement of this Award which would be a payment of deferred compensation within the meaning of Section 409A of the Code with respect to the Participant and is a settlement as a result of the Participant’s separation from service in connection with a Change in Control, the term “Change in Control” under the Plan shall mean a change in ownership or change in effective control for purposes of Section 409A of the Code. The payment of Award amounts under this Award Agreement described herein is hereby designated as a “separate payment” for purposes of Section 409A of the Code.

12. Definitions. For purposes of this Award Agreement:

or the subsidiary or Affiliate that either (i) employs the Participant or (ii) employed the Participant immediately prior to the Participant’s termination of Employment.

“ Forfeiture Event ” means the occurrence of at least one of the following (a) the Company is required, pursuant to a determination made by the Securities and Exchange Commission or by the Board, or an authorized subcommittee of the Board, to prepare a material accounting restatement due to the noncompliance of the Company with any financial reporting requirement under applicable securities laws as a result of misconduct, and the Board determines that (1) the Participant knowingly engaged in the misconduct, (2) the Participant was grossly negligent with respect to such misconduct or (3) the Participant knowingly or grossly negligently failed to prevent the misconduct or (b) the Board concludes that the Participant engaged in fraud, embezzlement or other similar misconduct materially detrimental to the Company.



	MPLX GP LLC


	By:
		Authorized Officer

EXHIBIT D

MPLX LP
2012 INCENTIVE COMPENSATION PLAN

PHANTOM UNIT AWARD AGREEMENT

OFFICER – GRANT

2. Vesting and Forfeiture of Phantom Units.

(a) The Phantom Units shall vest in three cumulative annual installments, as follows:


(i)	one-third of the Phantom Units shall vest on the first anniversary of the Grant Date;

(ii) an additional one-third of the Phantom Units shall vest on the second anniversary of the Grant Date; and

(iii) all remaining Phantom Units shall vest on the third anniversary of the Grant Date;

provided, however, that the Participant must be in continuous Employment from the Grant Date through the applicable vesting date in order for the applicable Phantom Units to vest. If the Employment of the Participant is terminated for any reason (including non-Mandatory Retirement) other than one listed in subparagraph (b)(i) – (iv) of this Paragraph 2, any Phantom Units that have not vested as of the date of such termination of Employment shall be immediately and 100% forfeited to the Company.

(b) The Phantom Units shall immediately vest in full, irrespective of the limitations set forth in subparagraph (a) above, upon the events set out below, provided such termination of Participant’s Employment constitutes a separation from service (within the meaning of Section 409A of the Code):


(i)	termination of the Participant’s Employment due to death;


(ii)	termination of the Participant’s Employment due to Mandatory Retirement;


(iii)	termination of Participant’s Employment upon the forced relocation of Participant’s principal place of Employment to a location more than 50 miles from Participant’s then-current principal place of Employment; or


(iv)	Participant’s Qualified Termination provided that as of such Qualified Termination the Participant has been in continuous Employment since the Grant Date.

4. Settlement and Issuance of Units. Subject to the terms of the Plan, all vested amounts payable to the Participant in respect of the Phantom Units, including the issuance of Units of the Partnership pursuant to this Paragraph 4, shall be settled in Units and for cash accruals credited under Paragraph 3 above, in cash, within sixty (60) days following the vesting date or as soon as reasonably practicable following the date on which such Phantom Units vest, but in no event later than March 15 of the year after the year in which the Phantom Units vest. During the period of time between the Grant Date and the date the Phantom Units settle, the Phantom Units will be evidenced by a credit to a bookkeeping account evidencing the unfunded and unsecured right of the Participant to receive Units, subject to the terms and conditions applicable to the Phantom Units. Following vesting and upon the settlement date as described above, the Participant shall be entitled to receive a number of Units of the Partnership equal to the total of the number of Phantom Units granted, with any fractional Phantom Units remaining settled in cash. Such Units shall be issued and registered in the name of the Participant. The Participant shall not have the right or be entitled to exercise any voting rights, receive cash distributions or dividends or have or be entitled to any rights as a Partnership unitholder in respect of the Phantom Units until such time as the Phantom Units have vested and been settled and corresponding Units of the Partnership have been issued.

6. Forfeiture or Repayment Resulting from Forfeiture Event.

7. Nonassignability. Upon the Participant’s death, the Phantom Units credited to the Participant under this Award Agreement shall be transferred to the Participant’s estate and upon such transfer settled in Units of the Partnership. Otherwise, the Participant may not sell, transfer, assign, pledge or otherwise encumber any portion of the Phantom Units, and any attempt to sell, transfer, assign, pledge or encumber any portion of the Phantom Units shall have no effect.

8. Nature of the Grant . Under this Award Agreement, the Participant is subject to the following conditions on the Award:

11. Officer Holding Requirement . Participant agrees that any Units of the Partnership received by the Participant in settlement of this Award shall be subject an additional holding period of one year from the date on which the Award is settled, during which holding period such Units (net of any Units of the Partnership used to satisfy the applicable tax withholding requirements) may not be sold or transferred by the Participant. This holding requirement shall cease to apply upon the death, retirement or other separation from service of the Participant during the holding period.

12. Section 409A . This Award is intended to comply with or be exempt from the requirements of Section 409A of the Code. Notwithstanding the foregoing, if the Participant is a “specified employee” as determined by the Company in accordance with its established policy, any settlement of Awards in this Award Agreement which would be a payment of deferred compensation within the meaning of Section 409A of the Code with respect to the Participant as a result of the Participant’s separation from service as defined under Section 409A of the Code (other than as a result of death) and which would otherwise be paid within six months of the Participant’s separation from service shall be payable on the date that is one day after the earlier of (i) the date that is six months after the Participant’s separation from service or (ii) the date that otherwise complies with the requirements of Section 409A of the Code. In addition, notwithstanding any provision of the Plan or this Award Agreement to the contrary, any settlement of the Phantom Units granted in this Award Agreement that would be a payment of deferred compensation within the meaning of Section 409A of the Code with respect to the Participant and is a settlement as a result of the Participant’s separation from service in connection with a Change in Control, the term “Change in Control” under the Plan shall mean a change in ownership or change in effective control for purposes of Section 409A of the Code. The payment of Award amounts under this Award Agreement described herein is hereby designated as a “separate payment” for purposes of Section 409A of the Code.

13. Definitions. For purposes of this Award Agreement:

“Employment” means employment with the Company or any of its subsidiaries or Affiliates including but not limited to MPC and its subsidiaries and Affiliates. For purposes of this Award Agreement, Employment shall also include any period of time during which the Participant is on Disability status. The length of any period of Employment shall be determined by the Company or the subsidiary or Affiliate that either (i) employs the Participant or (ii) employed the Participant immediately prior to the Participant’s termination of Employment.

misconduct or (3) the Participant knowingly or grossly negligently failed to prevent the misconduct or (b) the Board concludes that the Participant engaged in fraud, embezzlement or other similar misconduct materially detrimental to the Company.

“Mandatory Retirement” means termination of Employment as a result of the Company’s policy, if any, in effect at the time of the Grant Date, requiring the mandatory retirement of officers and/or other employees upon reaching a certain age or milestone.

“ Qualified Termination ” for purposes of this Award Agreement shall have the same definition as under the Marathon Petroleum Corporation Amended and Restated Executive Change in Control Severance Benefits Plan (the “CIC Plan”), as in effect on the Grant Date, and such definition and associated terms are hereby incorporated into this Award Agreement by reference. Notwithstanding the definition of a “Change in Control” under the terms of the CIC Plan, for purposes of this Award Agreement such Change in Control for purposes of determining whether a separation from service is a Qualified Termination shall include a Change in Control of either MPC, as the direct employer of the Participant, or a Change in Control of the Partnership, as the issuer of the Award.



	MPLX GP LLC


	By:
		Authorized Officer

EXHIBIT E

MARATHON PETROLEUM CORPORATION

2012 INCENTIVE COMPENSATION PLAN

1. Objectives . This Marathon Petroleum Corporation 2012 Incentive Compensation Plan (this “Plan”) is adopted by Marathon Petroleum Corporation (the “Corporation”) in order to retain employees and directors with a high degree of training, experience and ability; to attract new employees and directors whose services are considered particularly valuable; to encourage the sense of proprietorship of such persons; and to promote the active interest of such persons in the development and financial success of the Corporation and its Subsidiaries. These objectives are to be accomplished by making Awards under this Plan and thereby providing Participants with a proprietary interest in, and alignment with, the growth and performance of the Corporation and its Subsidiaries.

2. Definitions . As used herein, the terms set forth below shall have the following respective meanings:

“Administrator” means: (i) with respect to Employee Awards, the Committee, and (ii) with respect to Director Awards, the Board.

“Authorized Officer” means the Chief Executive Officer of the Corporation (or any other senior officer of the Corporation to whom he or she shall delegate the authority to execute any Award Agreement, where applicable).

“Award” means an Employee Award or a Director Award.

“Award Agreement” means any Employee Award Agreement or Director Award Agreement.

“Board” means the Board of Directors of the Corporation.

“Cash Award” means an award denominated in cash.

“Code” means the Internal Revenue Code of 1986, as amended from time to time.

“Committee” means the Compensation Committee of the Board and any successor committee to the Compensation Committee, as may be designated by the Board to administer this Plan in whole or in part.

“Common Stock” means Marathon Petroleum Corporation common stock, par value $.01 per share.

“Corporation” has the meaning set forth in paragraph 1 hereof.

“Director Award” means any Non-qualified Stock Option, Stock Appreciation Right, Stock Award, Restricted Stock Unit Award, Cash Award or Performance Award granted, whether singly, in combination or in tandem, to a Participant who is a Non-Employee Director pursuant to such applicable terms, conditions and limitations (including treatment as a Performance Award) as the Board may establish in order to fulfill the objectives of the Plan.

“Director Award Agreement” means an individual or common agreement contained within a separate plan document (in written or electronic form) setting forth the terms, conditions, and limitations applicable to a Director Award, to the extent the Board determines such agreement is necessary.

“Dividend Equivalents” means, with respect to shares of Restricted Stock or Restricted Stock Units, with respect to which shares are to be issued at the end of the Restriction Period, an amount equal to all dividends and other distributions (or the economic equivalent thereof) that are payable to shareholders of record during the Restriction Period on a like number of shares of Common Stock granted in the Award.

“Employee” means an employee of the Corporation or any of its Subsidiaries or an individual who has agreed to become an employee of the Corporation or any of its Subsidiaries and actually becomes an employee within the following six months. However, the term “Employee” shall not include any individual who owns directly or indirectly stock possessing more than five percent (5%) of the total combined voting power or value of all classes of stock of the Corporation or any Subsidiary.

“Employee Award” means any Option, Stock Appreciation Right, Stock Award, Restricted Stock Unit Award, Cash Award or Performance Award granted, whether singly, in combination or in tandem, to a Participant who is an Employee pursuant to such applicable terms, conditions and limitations (including treatment as a Performance Award) that the Committee may establish in order to fulfill the objectives of the Plan.

“Employee Award Agreement” means an agreement (in written or electronic form) setting forth the terms, conditions and limitations applicable to an Employee Award, to the extent the Committee determines such agreement is necessary or advisable.

“Equity Award” means any Option, Stock Appreciation Right, Stock Award or Performance Award (other than a Performance Award denominated in cash) granted to a Participant under the Plan.

“Executive Officer” means a “covered employee” within the meaning of Code § 162(m)(3) or any other executive officer designated by the Committee for purposes of exempting compensation payable under this Plan from the deduction limits of Code § 162(m).

“Fair Market Value” of a share of Common Stock means, as of a particular date: (i) if Common Stock is listed on a national securities exchange, the closing price per share of such Common Stock on the consolidated transaction reporting system for the principal national securities exchange on which shares of Common Stock are listed on that date, or, if there shall have been no such sale so reported on that date, on the next succeeding date on which such a sale is so reported, or, at the discretion of the Administrator, any other reasonable and objectively determinable method based on the listed price per share which reflects the price prevailing on the exchange at the time of grant; (ii) if Common Stock is not so listed but is quoted on a national securities market, the closing sales price per share of Common Stock reported on such market for such date, or, if there shall have been no such sale so reported on that date, on the next succeeding date on which such a sale is so reported; or (iii) if Common Stock is not so listed or quoted, the most recent value determined by an independent appraiser appointed by the Corporation for such purpose. For any determination of Fair Market Value, if the commitment to measure the Fair Market Value is based on the average trading price over a specified period, such period cannot extend more than 30 days before or 30 days after the grant date and such commitment must be irrevocably established for specified awards before the beginning of such period.

“Grant Date” means the effective date of the grant of an Award to a Participant pursuant to the Plan, which may be later than but shall never be earlier than the date on which the Committee (or its delegate) met or otherwise took action to effect the grant of such Award.

“Grant Price” means the price at which a Participant may exercise his or her right to receive cash or Common Stock, as applicable, under the terms of an Award.

“Incentive Stock Option” means an Option that is intended to comply with the requirements set forth in Code § 422.

“Non-Employee Director” means an individual serving as a member of the Board who is not then an Employee of the Corporation or any of its Subsidiaries.

“Non-qualified Stock Option” means an Option that is not an Incentive Stock Option.

“Option” means a right to purchase a specified number of shares of Common Stock at a specified Grant Price.

“Participant” means an Employee or Non-Employee Director to whom an Award has been granted under this Plan.

“Performance Award” means an Award made pursuant to this Plan, which Award is subject to the attainment of one or more Performance Goals.

“Performance Goal” means a standard established by the Committee to determine in whole or in part whether a Performance Award shall be earned.

“Plan” has the meaning set forth in paragraph 1 hereof.

“Recoupment Provision” means any clawback or recovery provision required by applicable law including United States federal and state securities laws or by any national securities exchange on which the Common Stock of the Corporation is listed or any applicable regulatory requirement.

“Restricted Stock” means Common Stock that is restricted or subject to forfeiture provisions.

“Restricted Stock Unit” means a unit evidencing the right to receive in specified circumstances one share of Common Stock or equivalent value (as determined by the Administrator) that is restricted or subject to forfeiture provisions.

“Restricted Stock Unit Award” means an Award in the form of Restricted Stock Units.

“Restriction Period” means a period of time beginning on the Grant Date of an Award of Restricted Stock or Restricted Stock Unit Award and ending on the date upon which the Common Stock subject to such Award, or equivalent value, is issued (if not previously issued), paid or is no longer restricted or subject to forfeiture provisions.

“Retirement” means termination of employment of an Employee on or after the time at which the Employee either (a) is eligible for retirement under the Marathon Petroleum Retirement Plan, or a successor retirement plan or (b) has attained age 50 and completed ten years of employment with the Corporation or its Subsidiaries, as applicable. However, the term Retirement does not include an event where immediately following which the Participant remains an Employee.

“Stock Appreciation Right” means a right to receive a payment, in cash or Common Stock, equal to the excess of the Fair Market Value or other specified valuation of a specified number of shares of Common Stock on the date the right is exercised over a specified Grant Price.

“Stock Award” means an Award in the form of, or denominated in, or by reference to, shares of Common Stock, including an award of Restricted Stock.

“Subsidiary” means: (i) in the case of a corporation, a “subsidiary corporation” of the Corporation as defined in Code § 424(f); and (ii) in the case of a partnership or other business entity not organized as a corporation, any such business entity of which the Corporation directly or indirectly owns 50% or more of the voting, capital or profits interests (whether in the form of partnership interests, membership interests, or otherwise).

3. Eligibility . All Employees are eligible for Employee Awards under this Plan in the sole discretion of the Committee. All Non-Employee Directors of the Corporation are eligible for Director Awards under this Plan in the sole discretion of the Board.

4. Common Stock Available for Awards . Subject to the provisions of paragraph 14 hereof, there shall be available for Awards under this Plan granted wholly or partly in Common Stock (including rights or options that may be exercised for or settled in Common Stock) an aggregate of 50 million shares of Common Stock. No more than 20 million shares of Common Stock may be the subject of Awards that are not Options or Stock Appreciation Rights. In the sole discretion of the Committee, 20 million shares of Common Stock may be granted as Incentive Stock Options.

(a) In connection with the granting of an Option or other Award, the number of shares of Common Stock available for issuance under this Plan shall be reduced by the number of shares of Common Stock in respect of which the Option or Award is granted or denominated. For example, upon the grant of stock-settled Stock Appreciation Rights, the number of shares of Common Stock available for issuance under this Plan shall be reduced by the full number of Stock Appreciation Rights granted, and the number of shares of Common Stock available for issuance under this Plan shall not thereafter be increased upon the exercise of the Stock Appreciation Rights and settlement in shares of Common Stock, even if the actual number of shares of Common Stock delivered in settlement of the Stock Appreciation Rights is less than the full number of Stock Appreciation Rights exercised. However, Awards that by their terms do not permit settlement in shares of Common Stock shall not reduce the number of shares of Common Stock available for issuance under this Plan.

(b) Any shares of Common Stock that are tendered by a Participant or withheld as full or partial payment of withholding or other taxes or as payment for the exercise or conversion price of an Award under this Plan shall not be added back to the number of shares of Common Stock available for issuance under this Plan.

(c) Whenever any outstanding Option or other Award (or portion thereof) expires, is cancelled or forfeited or is otherwise terminated for any reason without having been exercised or payment having been made in the form of shares of Common Stock, the number of shares of Common Stock available for issuance under this Plan shall be increased by the number of shares of Common Stock allocable to the expired, forfeited, cancelled or otherwise terminated Option or other Award (or portion thereof). To the extent that any Award is forfeited, or any Option or Stock Appreciation Right terminates, expires or lapses without being exercised, the shares of Common Stock subject to such Awards will not be counted as shares delivered under this Plan.

(d) Shares of Common Stock delivered under the Plan in settlement of an Award issued or made: (i) upon the assumption, substitution, conversion or replacement of outstanding awards under a plan or arrangement of an acquired entity; or (ii) as a post-transaction grant under such a plan or arrangement of an acquired entity, shall not reduce or be counted against the maximum number of shares of Common Stock available for delivery under the Plan, to the extent that the exemption for transactions in connection with mergers and acquisitions from the shareholders approval requirements of the New York Stock Exchange for equity compensation plans applies.

(e) Awards valued by reference to Common Stock that may be settled in equivalent cash value will count as shares of Common Stock delivered to the same extent as if the Award were settled in shares of Common Stock.

Consistent with the requirements specified in this paragraph 4, the Committee may from time to time adopt and observe such procedures concerning the counting of shares against this Plan maximum as it may deem appropriate, including rules more restrictive than those set forth above to the extent necessary to satisfy the requirements of any national securities exchange on which the Common Stock is listed or any applicable regulatory requirement. The Committee and the appropriate officers of the Corporation shall be authorized to, from time to time, take all such actions as any of them may determine are necessary or appropriate to file any documents with governmental authorities, stock exchanges and transaction reporting systems as may be required to ensure that shares of Common Stock are available for issuance pursuant to Awards.

5. Administration .

(a) Authority of the Committee. Subject to the terms of this Plan the Committee shall have the full and exclusive power and authority to administer this Plan with respect to Employee Awards and to take all actions that are specifically contemplated by this Plan or are necessary or appropriate in connection with the administration of this Plan. The Committee shall also have the full and exclusive authority to interpret this Plan and outstanding Employee Award Agreements and to adopt such rules, regulations and guidelines for carrying out this Plan as it may deem necessary or appropriate and the authority to amend this plan without further shareholder approval: (i) to comply with applicable law including United States federal and state securities laws or by any national securities exchange on which the common stock of the Corporation is listed or any applicable regularity requirements, or (ii) in any manner that is not considered to be a material revision of the Plan requiring shareholder approval. Amendments pursuant to this paragraph are permitted only to the extent that such amendments do not adversely affect the rights of any Participant under any Award previously granted to such Participant without the consent of such Participant. The Committee may correct any defect or supply any omission or reconcile any inconsistency in this Plan or in any Employee Award Agreement in the manner and to the extent the Committee deems necessary or desirable to further Plan purposes. Any decision of the Committee in the interpretation and administration of this Plan or any Employee Award Agreement shall lie within its sole discretion and shall be final, conclusive and binding on all parties concerned. All decisions and selections made by the Committee pursuant to the provisions of this Plan shall be made by a majority of its members unless subject to the Committee’s delegation of authority pursuant to paragraph 6 herein. The powers of the Committee shall include the authority (within the limitations described in this Plan):



	•		to determine the time when Employee Awards are to be granted and any conditions that must be satisfied before an Employee Award is granted;



	•		except as otherwise provided in paragraphs 7(a) and 12, to modify the terms of Employee Awards made under this Plan; and



	•		to determine the guidelines and/or procedures for the payment or exercise of Employee Awards.

(b) Limitation of Liability . No member of the Board or the Committee or officer of the Corporation to whom the Board or the Committee has delegated authority in accordance with the provisions of paragraph 6 of this Plan shall be liable for anything done or omitted to be done by him or her by any member of the Board or the Committee or by any officer of the Corporation in connection with the performance of any duties under this Plan, except for his or her own willful misconduct or as expressly provided by statute.

(c) Authority of the Board . The Board shall have the same powers, duties and authority to administer and interpret the Plan and all Director Awards outstanding under the Plan as the Committee retains with respect to Employee Awards, as described above.

(d) Prohibition on Repricing of Awards . No Option or Stock Appreciation Right may be repriced, replaced, regranted through cancellation or modified without shareholders approval (except as contemplated in paragraph 14 of this Plan), if the effect would be to reduce the exercise price for the shares underlying such Option or Stock Appreciation Right.

(e) Prohibition on Buy-out of Awards . No Option or Stock Appreciation Right may be bought back with cash without shareholder approval.

6. Delegation of Authority . The Committee may delegate to a subcommittee, the Chief Executive Officer or other senior officers of the Corporation, or to another committee of the Board, its duties or authority under this Plan with respect to Employee Awards, subject to such conditions or limitations as the Committee may establish; provided, however, that to the extent the Committee determines that it is necessary or desirable to exempt compensation payable under this Plan from the deduction limits of Code §162(m), the Committee will carry out such duties as may be required under Code § 162(m). The Board may delegate to the Committee or to another

committee of the Board, its administrative functions under this Plan with respect to Director Awards subject to such conditions or limitations as the Board may establish. The Committee or the Board or their delegates, as applicable, may engage or authorize engagement of a third party administrator to carry out administrative functions under the Plan.

7. Employee Awards .

(a) The Committee shall determine the type or types of Employee Awards to be made under this Plan and shall designate from time to time the Participants who are to be the recipients of such Employee Awards. Each Employee Award shall be evidenced in either an individual Employee Award Agreement or within a separate plan, policy, agreement or other written document, which shall reflect any vesting conditions or restrictions imposed by the Committee covering a period of time specified by the Committee and shall also contain such terms, conditions and limitations as shall be determined by the Committee in its sole discretion, including but not limited to applicable Recoupment Provisions. Where signature or electronic acceptance by the recipient of an award of the Employee Award Agreement is required, any such awards for which the Employee Award Agreement is not signed or electronically accepted within 11 months of the grant date shall be forfeited. Employee Awards may consist of those listed in this paragraph 7(a) and may be granted singly, in combination or in tandem. Employee Awards may also be made in combination or in tandem with, in replacement of, or as alternatives to, grants or rights under this Plan or any other plan of the Corporation or any of its Subsidiaries, including the plan of any acquired entity; provided that, except as contemplated in paragraph 14 hereof, without shareholders approval, no Option or Stock Appreciation Right may be issued in exchange for the cancellation of an Option or Stock Appreciation Right with a higher exercise price nor may the exercise price of any Option or Stock Appreciation Right be reduced. No Option or Stock Appreciation Right may include provisions that “reload” or “recycle” the Option or Stock Appreciation Right upon exercise or that extend the term of an Option or Stock Appreciation Right beyond ten years from its Grant Date. All or part of an Employee Award may be subject to conditions established by the Committee, which may include, but are not limited to, continuous service with the Corporation and its Subsidiaries and achievement of specific Performance Goals. Upon the termination of employment by a Participant who is an Employee, any unexercised, deferred, unvested, or unpaid Awards shall be treated as set forth in the applicable Employee Award Agreement.

(i) Option . An Employee Award may be in the form of an Option. An Option awarded to an Employee pursuant to this Plan may consist of an Incentive Stock Option or a Non-Qualified Stock Option and will be designated accordingly at the time of grant. The Grant Price of an Option shall be not less than the Fair Market Value of the Common Stock on the Grant Date. The term of an Option shall not exceed ten years from the Grant Date.

(ii) Stock Appreciation Right . An Employee Award may be in the form of a Stock Appreciation Right. The Grant Price for a Stock Appreciation Right shall not be less than the Fair Market Value of the Common Stock on the Grant Date. Any Stock Appreciation Right which is not a Performance Award shall have a minimum Restriction Period of three years from the Grant Date. However, (i) the Committee (or its designee) may provide for earlier vesting following a change of control or other specified events involving the Corporation or upon an Employee’s termination of employment by reason of death, Disability or Retirement; and (ii) vesting of a Stock Appreciation Right may occur incrementally over the three-year minimum Restricted Period, provided no portion of any Stock Appreciation Right Award will have a Restriction Period of less than one year. The term of a Stock Appreciation Right shall not exceed ten years from the Grant Date.

(iii) Restricted Stock. An Employee Award may be in the form of Restricted Stock. Any Restricted Stock awarded which is not a Performance Award shall have a minimum Restriction Period of three years from the Grant Date, provided that: (i) the Committee (or its designee) may provide for earlier vesting following a change of control or other specified events involving the Corporation or upon an Employee’s termination of employment by reason of death, Disability or Retirement; (ii) vesting of a Restricted Stock Award may occur incrementally over the three-year minimum Restricted Period, provided no portion of any Restricted Stock Award will have a

Restriction Period of less than one year; and (iii) no more than three percent (3%) of the total awards authorized under this Plan shall be available and are permitted to be granted to executives with shorter vesting periods than one year. Additionally employees who are officers at the time a Restricted Stock Award is made will have an additional one year holding after the end of the Restriction Period before such shares (net of shares used to satisfy applicable tax withholding) may be sold.

(iv) Restricted Stock Unit Award . An Employee Award may be in the form of a Restricted Stock Unit Award. Any Restricted Stock Unit Award which is not a Performance Award shall have a minimum Restriction Period of three years from the Grant Date, provided that: (i) the Committee (or its designee) may provide for earlier vesting following a change of control or other specified events involving the Corporation or upon an Employee’s termination of employment by reason of death, Disability or Retirement; (ii) vesting of a Restricted Stock Unit Award may occur incrementally over the three-year minimum Restricted Period, provided, no portion of any Restricted Stock Unit Award will have a Restriction Period of less than one year; and (iii) no more than three percent (3%) of the total awards authorized under this plan shall be available and are permitted to be granted with shorter vesting periods than one year to executives. Additionally employees who are officers at the time a Restricted Stock Unit Award is made that will settle in full-value shares will have an additional one year holding after the end of the Restriction Period before such shares (net of shares used to satisfy applicable tax withholding) may be sold.

(v) Rights of Holders of Restricted Stock and Restricted Stock Units. Unless otherwise provided in the Award Agreement, beginning on the date of grant of the Restricted Stock Award and subject to acceptance of the Award Agreement, the Participant shall become a shareholder of the Corporation with respect to all Shares subject to the Award Agreement and shall have all of the rights of a shareholder, including the right to vote such Shares and the right to receive distributions made with respect to such shares. A Participant receiving a Restricted Stock Unit Award shall not possess voting rights with respect to such Award. Except as otherwise provided in an Award Agreement any shares or any other property (other than cash) distributed as a dividend or otherwise with respect to any Restricted Stock Award or Restricted Stock Unit Award as to which the restrictions have not yet lapsed shall be subject to the same restrictions as such Restricted Stock Award or Restricted Stock Unit Award.

(vi) Performance Award . Without limiting the type or number of Employee Awards that may be made under the other provisions of this Plan, an Employee Award may be in the form of a Performance Award. Any Stock Award which is a Performance Award shall have a minimum Restriction Period of one year from the Grant Date, provided that the Committee (or its designee) may provide for earlier vesting following a change of control or other specified events involving the Corporation, or upon a termination of employment by reason of death, Disability or Retirement. Additionally employees who are officers at the time a Performance Award that will settle in full-value shares is made will have an additional one year holding after the Performance Period ends and the Performance Award is settled before such shares may be sold. The Committee shall set Performance Goals in its sole discretion which, depending on the extent to which they are met, may determine the value and/or amount of Performance Awards that will be paid out to the Participant and/or the portion of a Performance Award that may be exercised. A Performance Goal may include one or more of the following and need not be the same for each Participant:



	•		revenue and income measures (which include revenue, gross margin, income from operations, net income, net sales, earnings per share, earnings before interest, taxes, depreciation and amortization, earnings before interest, taxes and amortization, earnings before interest and taxes and economic value added);



	•		expense measures (which include costs of goods sold, selling, finding and development costs, general and administrative expenses and overhead costs);



	•		operating measures (which include refinery throughput, mechanical availability, productivity, operating income, funds from operations, product quality, cash from operations, after-tax operating income, market share, margin and sales volumes);



	•		margins (which include crack spread measures);



	•		refined product measures;



	•		cash management and cash flow measures (which include net cash flow from operating activities, working capital, receivables management and related customer terms);



	•		liquidity measures (which include earnings before or after the effect of certain items such as interest, taxes, depreciation and amortization, improvement in or attainment of working capital levels and free cash flow);



	•		leverage measures (which include debt-to-equity ratio, debt reduction and net debt);



	•		market measures (which include market share, stock price, growth measure, total shareholders return, share price performance, return on equity, return on invested capital and return on assets and market capitalization measures);



	•		return measures (which include return on equity, return on assets and return on invested capital);



	•		corporate value and sustainability measures (which include compliance, safety, environmental and personnel matters);



	•		project completion measures (which may include measures regarding whether interim milestones regarding budgets and deadlines are met, as well as whether projects are completed on time and on or under budget);



	•		other measures such as those relating to acquisitions, dispositions or customer satisfaction; and

Unless otherwise stated, such a Performance Goal need not be based upon an increase or positive result under a particular business criterion and could include, for example, maintaining the status quo, performance relative to a peer group determined by the Committee, or limiting economic losses (measured, in each case, by reference to specific business criteria). In interpreting Plan provisions applicable to Performance Goals and qualified Performance Awards, this Plan is intended to conform with Code § 162(m), including, without limitation, Treasury Regulations § 1.162-27(e), as to grants pursuant to this subsection and the Committee in establishing such goals and interpreting the Plan shall be guided by such provisions. The Committee may also substitute a Performance Goal or peer company(ies) during a measurement period or eliminate them and reallocate such weighting to the remaining Performance Goals if it concludes that the original goal(s) cannot be accurately measured or are no longer valid. Prior to the payment of any compensation based on the achievement of Performance Goals applicable to qualified Performance Awards, the Committee must certify in writing that applicable Performance Goals and any of the material terms thereof were, in fact, satisfied. Subject to the foregoing provisions, the terms, conditions and limitations applicable to any Performance Awards intended to qualify as performance-based compensation for purposes of Code § 162(m) shall be determined by the Committee to the extent required by Code § 162(m).

The Committee shall adjust the Performance Goals (either up or down) and the level of the Performance Award that a Participant may earn under this Plan if it determines that the occurrence of external changes or other unanticipated business conditions have materially affected the fairness of the goals and/or have unduly influenced the Corporation’s ability to meet them, including without limitation, events such as material acquisitions, force majeure events, unlawful acts committed against the Corporation or its property, labor disputes, legal mandates, asset write-downs, litigation, claims, judgments or settlements, the effect of changes in tax law or other such laws or provisions affecting reported results, accruals for reorganization and restructuring programs, changes in the capital structure of the Corporation and extraordinary accounting changes; provided, however, that Performance Awards granted to Executive Officers shall be adjusted only to the extent permitted under Code § 162(m). In addition, Performance Goals and Performance Awards shall be calculated without regard to any changes in accounting standards or codifications that may be required by the Financial Accounting Standards Board after such Performance Goals are established.

(vii) Notwithstanding anything to the contrary contained in this Plan, no Participant who is an Employee may be granted, during any one-year period, Employee Awards collectively consisting of: (i) Options or Stock Appreciation Rights that are exercisable for more than 6 million shares of Common Stock; or (ii) Stock Awards

covering or relating to more than 2 million shares of Common Stock (the limitation in clauses (i) and (ii) being collectively referred to as the “Stock-based Awards Limitations”). No Plan Participant who is an Employee may be granted Employee Awards consisting of cash (including Cash Awards that are granted as Performance Awards) in respect of any calendar year having a value determined on the Grant Date in excess of $20 million.

(viii) Cash Awards . An Employee Award may be in the form of a Cash Award. The criteria used to make such awards are the same as identified in paragraph 7(a)(vi) with the addition of subjective group, team or individual goals aligned to business results. Performance criteria and peer groups related to Cash Award payments may also be adjusted as provided for in paragraph 7(a)(vi).

8. Director Awards.

(a) The Board shall determine the type or types of Director Awards to be made under this Plan and shall designate from time to time the Participants who are to be the recipients of such Director Awards. Each Director Award shall be evidenced in either an individual Director Award Agreement, a common document including but not limited to a separate plan, policy, agreement or other written document, which shall contain such terms, conditions and limitations as shall be determined by the Board in its sole discretion, and may be signed by an Authorized Officer on behalf of the Corporation. Director Awards may consist of those listed in this paragraph 8(a) and may be granted singly, in combination or in tandem. Director Awards may also be made in combination or in tandem with, in replacement of, or as alternatives to, grants or rights under this Plan or any other plan of the Corporation or any of its Subsidiaries, including the plan of any acquired entity; provided that, except as contemplated in paragraph 14 hereof, without shareholders approval, no Option or Stock Appreciation Right may be issued in exchange for the cancellation of an Option or Stock Appreciation Right with a higher exercise price nor may the exercise price of any Option or Stock Appreciation Right be reduced without shareholder approval. No Option or Stock Appreciation Right may include provisions that “reload” or “recycle” the Option or Stock Appreciation Right upon exercise or that extend the term of an Option or Stock Appreciation Right beyond ten years from its Grant Date. All or part of a Director Award may be subject to conditions established by the Board, which may include, but are not limited to, continuous service with the Corporation and its Subsidiaries and achievement of specific Performance Goals. Upon the termination of service by a Participant who is a Director, any unexercised, deferred, unvested or unpaid Awards shall be treated as set forth in the applicable Director Award Agreement.

(i) Option . A Director Award may be in the form of an Option. An Option awarded to a Director pursuant to this Plan shall be a Non-Qualified Stock Option. The Grant Price of an Option shall be not less than the Fair Market Value of the Common Stock on the Grant Date. The term of an Option shall not exceed ten years from the Grant Date.

(ii) Stock Appreciation Right . A Director Award may be in the form of a Stock Appreciation Right. The Grant Price for a Stock Appreciation Right shall not be less than the Fair Market Value of the Common Stock on the Grant Date. The term of a Stock Appreciation Right shall not exceed ten years from the Grant Date.

(iii) Stock Award . A Director Award may be in the form of a Stock Award. Terms, conditions and limitations applicable to a Stock Award granted to a Non-Employee Director pursuant to this Plan shall be determined by the Board.

(iv) Restricted Stock Unit Award . A Director Award may be in the form of a Restricted Stock Unit Award. Terms, conditions and limitations applicable to a Restricted Stock Unit Award granted to a Non-Employee Director pursuant to this Plan shall be determined by the Board.

(v) Cash Awards . A Director Award may be in the form of a Cash Award.

(vi) Performance Award . Without limiting the type or number of Director Awards that may be made under the other provisions of this Plan, a Director Award may be in the form of a Performance Award. Terms, conditions and limitations applicable to any Performance Award granted to a Non-Employee Director pursuant to this Plan shall be determined by the Board. The Board shall set performance goals in its discretion which, depending on the extent to which they are met, may determine the value and/or amount of Performance Awards that will be paid out to the Non-Employee Directors.

9. Award Payment; Dividends; Substitution; Fractional Shares .

(a) General . Payment of Awards may be made in the form of cash or Common Stock, or a combination thereof, and may include such restrictions as the Administrator shall determine, including, in the case of Common Stock, restrictions on transfer and forfeiture provisions. If payment of an Award is made in the form of Restricted Stock, such shares may be issued at the beginning or end of the Restriction Period. In the event that shares of Restricted Stock are to be issued at the beginning of the Restriction Period, the certificates evidencing such shares (to the extent that such shares are so evidenced) shall contain appropriate legends and restrictions that describe the terms and conditions of the restrictions applicable to such shares. In the event that shares of Restricted Stock are to be issued at the end of the Restricted Period, the right to receive such shares shall be evidenced by book entry registration or in such other manner as the Administrator may determine.

(b) Dividends and Interest . Rights to dividends or Dividend Equivalents may be extended to and made part of any Award consisting of shares of Common Stock or units denominated in shares of Common Stock, subject to such terms, conditions and restrictions as the Administrator may establish. The Administrator may also establish rules and procedures for the crediting of interest on deferred cash payments and Dividend Equivalents for Awards consisting of shares of Common Stock or units denominated in shares of Common Stock.

(c) Fractional Shares . No fractional shares shall be issued or delivered pursuant to any Award under this Plan. The Administrator shall determine whether cash, Awards or other property shall be issued or paid in lieu of fractional shares, or whether fractional shares or any rights thereto shall be forfeited or otherwise eliminated.

10. Stock Option and Stock Appreciation Right Exercise . The Grant Price of an Option or Stock Appreciation Right shall be paid in full at the time of exercise in cash or, if elected by the Participant, the Participant may purchase such shares by means of tendering Common Stock valued at Fair Market Value on the date of exercise, or any combination thereof. The Administrator, in its sole discretion, shall determine acceptable methods for Participants to tender Common Stock. Subject to applicable law, Options or Stock Appreciation Rights may also be exercised through “cashless exercise” procedures approved by the Administrator.

11. Taxes . The Corporation or its third party administrator shall have the right to deduct applicable taxes from any Award payment and withhold, at the time of delivery or vesting of cash or shares of Common Stock under this Plan, an appropriate amount of cash or number of shares of Common Stock or a combination thereof for payment of taxes required by law or to take such other action as may be necessary in the opinion of the Corporation to satisfy all obligations for withholding of such taxes. The Administrator may also permit withholding to be satisfied by the transfer to the Corporation of shares of Common Stock owned by the holder of the Award with respect to which withholding is required. If shares of Common Stock are used to satisfy tax withholding, such shares shall be valued at Fair Market Value on the date when the tax withholding is required to be made.

12. Amendment, Modification, Suspension or Termination . The Board or the Committee may amend, modify, suspend or terminate this Plan for the purpose of meeting or addressing any changes in legal requirements or for any other purpose permitted by law, except that: (i) no amendment or alteration that would materially adversely affect the rights of any Participant under any Award previously granted to such Participant shall be made without the consent of such Participant; and (ii) no amendment or alteration shall be effective prior to its approval by the shareholders of the Corporation to the extent shareholder approval is otherwise required by applicable legal requirements or the requirements of any exchange on which the Common Stock is listed. Notwithstanding the foregoing, no amendment may cause an Option or Stock Appreciation Right to be repriced,

replaced, bought back, regranted through cancellation or modified without shareholder approval (except as provided in paragraph 14), if the effect of such amendment would be to reduce the exercise price for the shares underlying such Option or Stock Appreciation Right.

13. Assignability . Unless otherwise determined by the Committee in the Award Agreement, no Award or any other benefit under this Plan shall be assignable or otherwise transferable, except by will or the laws of descent and distribution. Any attempted assignment of an Award or any other benefit under this Plan in violation of this paragraph 13 shall be null and void.

14. Adjustments .

(a) The existence of this Plan and Awards granted hereunder shall not affect in any way the right or power of the Corporation or its shareholders to make or authorize any or all adjustments, recapitalizations, reorganizations or other changes in the Corporation’s capital structure or its business, or any merger or consolidation of the Corporation, or any issue of bonds, debentures, preferred, or prior preference stocks ahead of or affecting the shares of Common Stock or the rights thereof, or the dissolution or liquidation of the Corporation, or any sale or transfer of all or any part of its assets or business or any other corporate act or proceeding, whether of a similar character or otherwise.

(b) Except as provided in this Plan, the issue by the Corporation of shares of stock of any class, or securities convertible into shares of stock of any class, for cash or property, or for labor or services, either upon direct sale or upon exercise of rights or warrants to subscribe therefore, or upon conversion of shares or obligations of the Corporation convertible into such shares or other securities, shall not affect, and no adjustment by reason thereof shall be made with respect to, the number of shares of Common Stock subject to Awards granted hereunder.

(c) If the Corporation shall effect a subdivision or consolidation of shares or other capital adjustments, adoption of any plan of exchange affecting Common Stock, a distribution to holders of Common Stock of securities or other property (other than normal cash dividends), the payment of a stock dividend or other increase or reduction of the number of shares of the Common Stock outstanding without receiving compensation in money, services or property, then (i) the number of shares of Common Stock subject to this Plan, (ii) the Stock-based Awards Limitations, (iii) the number of shares of Common Stock covered by outstanding Awards, (iv) the Grant Prices of all outstanding Awards, and (v) the appropriate Fair Market Values determined for such Awards shall each be adjusted proportionately by the Board as appropriate to reflect such transaction.

(d) In the event of a corporate merger, consolidation, acquisition of property or stock, separation, reorganization or liquidation, the Board may make such adjustments to Awards or other provisions for the disposition of Awards as it deems equitable, and shall be authorized, in its sole discretion: (i) to provide for the substitution of a new Award or other arrangement (which, if applicable, may be exercisable for such property or stock as the Board determines) for an Award or the assumption of the Award, regardless of whether in a transaction to which Code § 424(a) applies; (ii) to provide, prior to the transaction, for the acceleration of the vesting and exercisability of, or lapse of restrictions with respect to, the Award; or (iii) to cancel any such Awards and to deliver to the Participants cash in an amount that the Board shall determine in its sole discretion is equal to the Fair Market Value of such Awards on the date of such event, which in the case of Options or Stock Appreciation Rights shall be the excess of the Fair Market Value of Common Stock on such date over the exercise price of such Award. For the avoidance of doubt, if the exercise price is less than Fair Market Value the Option or Stock Appreciation Right may be canceled for no consideration.

(e) Notwithstanding the foregoing: (i) any adjustments made pursuant to this paragraph 14 to Awards that are considered “deferred compensation” within the meaning of Code § 409A shall be made in a manner which is intended to not result in accelerated or additional tax to a Participant pursuant to Code § 409A and (ii) any adjustments made pursuant to this paragraph 14 to Awards that are not considered “deferred compensation” subject to Code § 409A shall be made in such a manner intended to ensure that after such adjustment, the Awards either: (A) continue not to be subject to Code § 409A; or (B) do not result in accelerated or additional tax to a Participant pursuant to Code § 409A.

15. Restrictions . No Common Stock or other form of payment shall be issued and no payment shall be made with respect to any Award unless the Corporation shall be satisfied based on the advice of its counsel that such issuance will be in compliance with the rules of any securities exchange on which the Common Stock is listed and applicable laws, including United States federal and state securities laws. Certificates (if any) or other writings evidencing shares of Common Stock delivered under this Plan (to the extent that such shares are so evidenced) may be subject to such stop transfer orders and other restrictions as the Administrator may deem advisable under the rules, regulations and other requirements of the Securities and Exchange Commission, any securities exchange or transaction reporting system upon which the Common Stock is then listed or to which it is admitted for quotation and any applicable federal or state securities law. The Administrator may cause a legend or legends to be placed upon such certificates or other writings to make appropriate reference to such restrictions.

16. Unfunded Plan . This Plan shall be unfunded. Although bookkeeping accounts may be established with respect to Participants who are entitled to cash, Common Stock or rights thereto under this Plan, any such accounts shall be used merely as a bookkeeping convenience. The Corporation shall not be required to segregate any assets that may at any time be represented by cash, Common Stock, or rights thereto, nor shall this Plan be construed as providing for such segregation, nor shall the Corporation, the Board or the Committee be deemed to be a trustee of any cash, Common Stock or rights thereto to be granted under this Plan. Any liability or obligation of the Corporation to any Participant with respect to an Award of cash, Common Stock or rights thereto under this Plan shall be based solely upon any contractual obligations that may be created by this Plan and any Award Agreement, and no such liability or obligation of the Corporation shall be deemed to be secured by any pledge or other encumbrance on any property of the Corporation. Neither the Corporation nor the Board nor the Committee shall be required to give any security or bond for the performance of any obligation that may be created by this Plan.

17. Code Section 409A . This Plan is intended to provide compensation which is exempt from or which complies with Code § 409A, and ambiguous provisions of this Plan or any Award Agreement, if any, shall be construed in a manner that would cause Awards to be compliant with or exempt from the application of Code § 409A, as appropriate. For purposes of Code § 409A, each payment under this Plan shall be deemed to be a separate payment. To the extent that it is determined that an Award will be subject to Code § 409A additional provisions, terms and conditions will apply as necessary to comply with Code § 409A and will be reflected in the applicable Employee Award Agreement and such terms will govern with respect to that Award notwithstanding any provision of this Plan to the contrary.

Notwithstanding any provision of this Plan to the contrary, if a Participant is a “specified employee” within the meaning of Code § 409A as of the date of such Participant’s termination of employment and the Corporation determines, in good faith, that immediate payment of any amounts or benefits under this Plan would cause a violation of Code § 409A, then any amounts or benefits which are payable under this Plan upon the Participant’s “separation from service” within the meaning of Code § 409A which: (i) are subject to the provisions of Code § 409A; (ii) are not otherwise excluded under Code § 409A; and (iii) would otherwise be payable during the first six-month period following such separation from service, shall be paid as soon as practicable the first business day next following the earlier of: (1) the date that is six months and one day following the date of termination; or (2) the date of the Participant’s death.

18. Governing Law . This Plan and all determinations made and actions taken pursuant hereto, to the extent not otherwise governed by mandatory provisions of the Code or the securities laws of the United States, shall be governed by and construed in accordance with the laws of the State of Delaware.

19. No Right to Employment . Nothing in this Plan or an Award Agreement shall interfere with or limit in any way the right of the Corporation or a Subsidiary to terminate any Participant’s employment or other service relationship at any time, nor confer upon any Participant any right to continue in the capacity in which he or she is employed or otherwise serves the Corporation or any Subsidiary.

20. Successors . All obligations of the Corporation under this Plan with respect to Awards granted hereunder shall be binding on any successor to the Corporation, whether the existence of such successor is the result of a direct or indirect purchase, merger, consolidation or otherwise, of all or substantially all of the business and/or assets of the Corporation.

21. Tax Consequences . Nothing in this Plan or an Award Agreement shall constitute a representation by the Corporation to a Participant regarding the tax consequences of any Award received by a Participant under this Plan. Although the Corporation may endeavor to: (i) qualify a Performance Award for favorable United States or foreign tax treatment; or (ii) avoid adverse tax treatment ( e.g. , under Code § 409A), the Corporation makes no representation to that effect and expressly disavows any covenant to maintain favorable or unavoidable tax treatment. The Corporation shall be unconstrained in its corporate activities without regard to the potential negative tax impact on holders of Performance Awards under this Plan.

22. Non-United States Participants . The Board or Committee may grant Awards to persons outside the United States under such terms and conditions as may, in the judgment of the Board or Committee, as applicable, be necessary or advisable to comply with the laws of the applicable foreign jurisdictions and, to that end, may establish sub-plans, modified vesting, exercise or settlement procedures and other terms and procedures. Notwithstanding the above, neither the Board nor the Committee may take any actions under this Plan, and no Awards shall be granted, that would violate the Securities Exchange Act of 1934, the Code or any other applicable law.

23. Effectiveness . Subject to shareholder approval, this Plan is effective April 25, 2012. This Plan shall continue in effect for a term of ten years after the date on which the shareholders of the Corporation first approved this Plan, which was April 25, 2012, unless sooner terminated by action of the Board.

EXHIBIT F

MARATHON PETROLEUM CORPORATION

RESTRICTED STOCK AWARD AGREEMENT

OFFICER – 3-YEAR CLIFF VESTING

As evidenced by this Award Agreement and under the Marathon Petroleum Corporation 2012 Incentive Compensation Plan (the “Plan”), Marathon Petroleum Corporation (the “Corporation”) has granted to [NAME] (the “Participant”), an employee of the Corporation or a Subsidiary, on [DATE] (the “Grant Date”), [NUMBER] shares of Restricted Stock (“Restricted Shares”). The number of Restricted Shares awarded is subject to adjustment as provided in the Plan, and the Restricted Shares are subject to the following terms and conditions:

1. Relationship to the Plan. This grant of Restricted Shares is subject to all of the terms, conditions and provisions of the Plan and administrative interpretations thereunder, if any, that have been adopted by the Committee. Except as otherwise defined in this Award Agreement, capitalized terms shall have the same meanings given to them under the Plan. To the extent that any provision of this Award Agreement conflicts with the express terms of the Plan, the terms of the Plan shall control and, if necessary, the applicable provisions of this Award Agreement shall be hereby deemed amended so as to carry out the purpose and intent of the Plan.


2.	Vesting and Forfeiture of Restricted Shares.

(a) The Restricted Shares shall vest on the third anniversary of the Grant Date; provided, however, that the Participant must be in continuous Employment from the Grant Date through the vesting date in order for the Restricted Shares to vest. If the Employment of the Participant is terminated for any reason (including non-Mandatory Retirement) other than one listed in subparagraph (b)(i) – (iv) of this Paragraph 2, any Restricted Shares that have not vested as of the date of such termination of Employment shall be immediately and 100% forfeited to the Corporation.

(b) The Restricted Shares shall immediately vest in full, irrespective of the limitations set forth in subparagraph (a) of this Paragraph 2, upon the events set out below:


i.	termination of the Participant’s Employment due to death;


ii.	Participant’s “separation from service” (within the meaning of Section 409A of the Code) upon the forced relocation of Participant’s principal place of employment to a location more than 50 miles from Participant's then-current principal place of employment;


iii.	termination of the Participant’s Employment due to Mandatory Retirement; or


iv.	Participant’s Qualified Termination provided that as of such Qualified Termination the Participant has been in continuous Employment since the Grant Date.

3. Issuance of Shares. Effective as of the Grant Date, the Committee or its designated representative shall cause a number of shares of Common Stock equal to the number of Restricted Shares to be issued and registered in the Participant’s name, subject to the conditions and restrictions set forth in this Award Agreement and the Plan.

Such issuance and registration shall be evidenced by an entry on the registry books of the Corporation. Any book entries evidencing the Restricted Shares shall carry or be endorsed with a legend referring to the conditions and restrictions set forth in this Award Agreement and the Plan. The Participant shall not be entitled to release of the restrictions on the book entry evidencing such Restricted Shares for any portion of the Restricted Shares unless and until the related Restricted Shares have vested pursuant to Paragraph 2. In the event the Restricted Shares are forfeited in full or in part, the Participant hereby consents to the relinquishment of the forfeited Restricted Shares theretofore issued and registered in the Participant’s name to the Corporation at that time.

4. Forfeiture or Repayment Resulting from Forfeiture Event.

(a) If there is a Forfeiture Event either during the Participant’s Employment or within two years after termination of the Participant’s Employment, then the Committee may, but is not obligated to, cause all of the Participant’s unvested Restricted Shares to be forfeited by the Participant and returned to the Corporation.

(b) If there is a Forfeiture Event either during the Participant’s Employment or within two years after termination of the Participant’s Employment, then with respect to Restricted Shares granted under this Award Agreement that have vested, the Committee may, but is not obligated to, require that the Participant pay to the Corporation an amount (the “Forfeiture Amount”) up to (but not in excess of) the lesser of (i) the value of such previously vested Restricted Shares as of the date such shares vested or (ii) the value of such previously vested Restricted Shares as of the date on which the Committee makes a demand for payment of the Forfeiture Amount. Any Forfeiture Amount shall be paid by the Participant within sixty (60) days of receipt from the Corporation of written notice requiring payment of such Forfeiture Amount.

(c) This Paragraph 4 shall apply notwithstanding any provision of this Award Agreement to the contrary and is meant to provide the Corporation with rights in addition to any other remedy which may exist in law or in equity. This Paragraph 4 shall not apply to the Participant following the effective time of a Change in Control.

(d) Notwithstanding the foregoing or any other provision of this Award Agreement to the contrary, the Participant agrees that the Corporation may also require that the Participant repay to the Corporation any compensation paid to the Participant under this Award Agreement, as is required by the provisions of the Dodd-Frank Wall Street Reform and Consumer Protection Act and the regulations thereunder or any other “clawback” provisions as required by law or by the applicable listing standards of the exchange on which the Common Stock is listed for trading.

5. Taxes. Pursuant to the applicable provisions of the Plan, the Corporation or its designated representative shall have the right to withhold applicable taxes from the shares of Common Stock otherwise deliverable to the Participant due to the vesting of Restricted Shares pursuant to this Award Agreement, or from other compensation payable to the Participant, at the time of the vesting and delivery of such shares.

6. Shareholder Rights. Unless and until the Restricted Shares are forfeited, the Participant shall have the rights of a shareholder with respect to the Restricted Shares as of the Grant Date, including the right to vote the Restricted Shares and the right to receive dividends. The Participant hereby consents to receiving any dividends on the unvested Restricted Shares through the Corporation’s payroll and, accordingly, directs the Corporation’s transfer agent to pay such dividends to the Corporation on his or her behalf.

7. Nonassignability. Upon the Participant’s death, the Restricted Shares shall be transferred to the Participant’s estate. Otherwise, the Participant may not sell, transfer, assign, pledge or otherwise encumber any portion of the Restricted Shares, and any attempt to sell, transfer, assign, pledge or encumber any portion of the Restricted Shares shall have no effect.

8. No Employment Guaranteed. Nothing in this Award Agreement shall give the Participant any rights to (or impose any obligations for) continued Employment by the Corporation or any Subsidiary or successor, nor shall it give such entities any rights (or impose any obligations) with respect to continued performance of duties by the Participant.

9. Modification of Agreement. Any modification of this Award Agreement shall be binding only if evidenced in writing and signed by an authorized representative of the Corporation, provided that no modification may, without the consent of the Participant, adversely affect the rights of the Participant hereunder.

10. Officer Holding Requirement . Participant agrees that any shares vested under this Award shall be subject an additional holding period of one year from the date on which the Award is settled, during which holding period such shares (net of shares used to satisfy the applicable tax withholding requirements) may not be sold or transferred by the Participant. This holding requirement shall cease to apply upon the death, retirement or other separation from service of the Participant during the holding period.

11. Definitions. For purposes of this Award Agreement:

“Employment” means employment with the Corporation or any of its Subsidiaries. For purposes of this Award Agreement, Employment shall also include any period of time during which the Participant is on Disability status. The length of any period of Employment shall be determined by the Corporation or the Subsidiary that either (i) employs the Participant or (ii) employed the Participant immediately prior to the Participant’s termination of Employment.

“ Forfeiture Event ” means the occurrence of at least one of the following (a) the Corporation is required, pursuant to a determination made by the Securities and Exchange Commission or by the Audit Committee of the Board, to prepare a material accounting restatement due to the noncompliance of the Corporation with any financial reporting requirement under applicable securities laws as a result of misconduct, and the Committee determines that (1) the Participant knowingly engaged in the misconduct, (2) the Participant was grossly negligent with respect to such misconduct or (3) the Participant knowingly or grossly negligently failed to prevent the misconduct or (b) the Committee concludes that the Participant engaged in fraud, embezzlement or other similar misconduct materially detrimental to the Corporation.

“Mandatory Retirement” means termination of Employment as a result of the Corporation’s policy, if any, in effect at the time of the Grant Date, requiring the mandatory retirement of officers and/or other employees upon reaching a certain age or milestone.



	Marathon Petroleum Corporation


	By:
		Authorized Officer

RETENTION AGREEMENT

THIS RETENTION AGREEMENT ("Retention Agreement"), is made and entered into on November 12, 2015, by and between Marathon Petroleum Company LP (the "Company"), and John C. Mollenkopf ("Executive") to be effective as of the closing of the Merger.

RECITALS

WHEREAS, Executive and MarkWest Hydrocarbon, Inc., a subsidiary of MarkWest Energy Partners, L. P., are parties to that certain Employment Agreement dated, September 5, 2007, a copy of which is attached hereto as Exhibit A ("Prior Agreement"), under which Executive is entitled to, among other things, lump sum cash severance benefits as described in Section 5(a) of the Prior Agreement ("Severance Benefits") upon certain terminations of employment, including a qualifying voluntary termination by Executive under Section 5(e)(ii)(E) of the Prior Agreement within one year of a "Change of Control" (as such term is defined in the Prior Agreement);

WHEREAS, on July 11, 2015, MarkWest Energy Partners, L. P. entered into an Agreement and Plan of Merger among MPLX LP, MPLX GP LLC, Marathon Petroleum Corporation, and Sapphire Holdco LLC, as amended (the "Merger Agreement"), pursuant to which Sapphire Holdco LLC will be merged with and into MarkWest Energy Partners, L.P., with MarkWest Energy Partners, L.P. continuing as the surviving entity (the "Merger");

WHEREAS, if consummated, the Merger would constitute a Change of Control under the Prior Agreement and, following the Closing, Executive would become an employee of the Company or one of its wholly owned subsidiaries (rather than an employee of MarkWest Hydrocarbon, Inc.), but Executive would continue to provide services to MarkWest Energy Partners, L.P. and certain related entities; and

WHEREAS, Executive and the Company now desire, contingent on the closing of the Merger, to enter into this Retention Agreement as of the date hereof, which Retention Agreement shall become effective contingent upon the closing of the Merger ("Closing").

NOW, THEREFORE, contingent on the Closing, in consideration of the mu tua l promises contained herein, and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, Executive and the Company (the "Parties"), intending to be legally bound, hereby agree as provided herein.

1. Termination of Prior Agreement. Executive and the Company mutually agree that, notwithstanding anything in the Prior Agreement to the contrary, except as provided in this Retention Agreement, the Prior Agreement (and the Term (as defined in the Prior Agreement) of the Prior Agreement) shall terminate, without penalty, on the date on which the Closing actually occurs (the "Closing Date") and, from and after the Closing Date, neither Executive nor the Company shall have any rights or obligations under the

Prior Agreement. For the sake of clarity, as of the Closing Date, Executive shall not have any rights or entitlement to the Severance Benefits under the Prior Agreement. Executive shall, however, be entitled to the accelerated vesting of equity awards under any MarkWest Hydrocarbon, Inc. or MarkWest Energy Partners, L.P. equity plan or under Section 3(c)(ii) of the Prior Agreement that will come due as a consequence of the Change of Control resulting from the consummation of the Merger.

Position and Duties. Commencing on the Closing Date, Executive shall serve as Executive Vice President and Chief Operating Officer at MPLX GP . During Executive's continued employment with the Company or its Affiliates, Executive shall perform the duties assigned to Executive from time to time by the Company's Chief Executive Officer or its designee from time to time, and Executive shall devote substantially all of Executive’s full business time, attention and effort to the affairs of the Company and its Affiliates and shall use reasonable best efforts to promote the interests of the Company and its Affiliates. As used in this Retention Agreement, "Affiliate" means, with respect to any entity, any other entity that directly or indirectly controls, is controlled by, or is under common control with such first entity, and specifically includes any entity that is under common control with Marathon Petroleum Corporation.


3.	Compensation and Benefits.


a.	Salary. For services commencing on the Closing Date, the Company shall pay, or shall cause Executive's then-current employer to pay, Executive in accordance with its normal payroll practices an annual salary at a rate of $480,000 per year. Executive will be eligible for a market-based pay increase in April of 2016 and each succeeding April thereafter in accordance with Company practices.

Retention Bonus. As soon as administratively feasible after the Closing Date, but in no event later than the 1 st day of the month coincident with or next following the Closing Date, Executive shall be granted an award cumulatively valued in the amount of $5,032,160 as of the actual grant date . The award, as described in the prior sentence, shall be divided into separate grants, as set out below.


i.	Retention Award . Executive shall be granted a retention award in the amount of $1,992,160 (the "Retention Award"). The Retention Award shall be paid part in cash (the "Cash Portion") and part in phantom partnership units of MPLX LP (the "Equity Portion").

The Cash Portion of the Retention Award shall be equal to the sum of (i) the employee portion of the Federal Insurance Contribution Act ("FICA") taxes that are due and required to be withheld upon grant of the Retention Award ("FICA Amount") plus, (ii) all income tax withholdings due as a result of the taxable nature of the payment of the FICA Amount (it being understood that the amounts in this subsection (ii) must be calculated iteratively to

account for the circular nature of the income tax withholding obligations related to the payment of the FICA Amount and the related i ncome tax withholdings) . The Cash Portion shall be timely remitted directly to the relevant taxing authorities.

The Equity Portion shall equal the excess of (i) the Retention Award, over (ii) the Cash Portion. The Equity Portion shall consist of phantom partnership units of MPLX LP valued as of the actual grant date. As will be provided in the applicable award agreement, the phantom partnership units and accrued DERS/distributions shall vest and become payable upon Executive's separation from service (within the meaning of Section 409A of the Internal Revenue Code of 1986, as amended (the "Code")) from the applicable Code Section 409A "service recipient" with respect to the Retention Award (as defined in Treasury Regulation 1.409A l(h)(3) for any reason and at any time, except if Executive's separation from service is due to the termination of his employment for Cause (as defined in Section 4(b) of the Prior Agreement, except that the terms "Board," "Company," and "Partnership," as used in Section 4(b) of the Prior Agreement shall mean the Company, as herein defined, or the Executive's employer, as the case may be). If Executive's "separation from service" is due to the termination of his employment for Cause, the Retention Award and the phantom partnership units under this Paragraph 3.b.i . shall be forfeited in their entirety. The phantom partnership units contemplated under this Paragraph 3.b.i. shall be subject to the terms and conditions of the MPLX LP 2012 Incentive Compensation Plan, attached hereto as Exhibit B, and the applicable award agreement, which shall be similar in form to the MPLX LP 2012 Incentive Compensation Plan Phantom Unit Award Agreement, attached hereto as Exhibit C. For the sake of clarity, it is the intention of the parties that Executive will not incur a "separation from service" for purposes of this Paragraph 3.b.i. when or if Executive ' s employment with MarkWest Hydrocarbon, Inc. is transferred to the Company or its Affiliates so long as Executive continues to provide sufficient services to MarkWest Energy Partners, L.P. and certain related entities pursuant to Treasury Regulation 1.409A-l(h)(l)(ii).

ii. Additional Long-Term Incentive Award. Executive shall be granted phantom partnership units of MPLX LP valued in the amount of $2 ,040,000, as o f the act ua l grant date. As will be provided in the applicable award agreement, the award will vest in three cumulative annual installments, as follows : (1) one-third of the phantom partnership units shall vest on the first anniversary of the grant date; (2) an additional one-third of the phantom partnership units shall vest on the second

anniversary of the grant date; and (3) all remaining phantom partnership units shall vest on the third anniversary of the grant date; provided, however , that except as provided below or in the applicable award agreement, Executive must be providing continuous service to Marathon Petroleum Corporation or any of its subsidiaries or Affiliates from the grant date through the applicable vesting date in order for the phantom partnership units to vest. Notwithstanding the foregoing, the applicable award agreement will provide that the phantom partnership units contemplated under this Paragraph 3.b.ii shall become fully vested upon Executive's separation from service as a result of the forced relocation of Executive's principal place of employment to a location more than 50 miles from Executive's then-current principal place of employment. The award of the phantom partnership units contemplated under this Paragraph

3 . b.ii. shall be subject to the terms and conditions of the MPLX LP 2012 Incentive Compensation Plan, attached hereto as Exhibit B, and the applicable award agreement, which shall be similar in form to the MPLX LP 2012 Incentive Compensation Plan Phantom Unit Award Agreement, attached hereto as Exhibit D.

iii. Retention Bonus Award. Executive shall be granted restricted stock of Marathon Petroleum Corporation, valued in the amount of $1,000,000 as of the actual grant date. As will be provided in the applicable award agreement, the award will vest in full on the third anniversary of the grant date; provided, however , that except as provided below or in the applicable award agreement, Executive must be providing continuous service to Marathon Petroleum Corporation or any of its subsidiaries or Affiliates from the grant date through the applicable vesting date in order for the restricted stock award to vest. Notwithstanding the foregoing, the applicable award agreement will provide that the restricted stock contemplated under this Paragraph 3.b.iii shall become fully vested upon Executive's separation from service as a result of the forced relocation of Executive's principal place of employment to a location more than 50 miles from Executive's then-current principal place of employment. The award of restricted stock of Marathon Petroleum Corporation contemplated under this Paragraph 3.b.iii. shall be subject to the terms and conditions of the Marathon Petroleum Corporation 2012 Incentive Compensation Plan, as amended, attached hereto as Exhibit E , and the applicable award agreement, which shall be similar in form to the Marathon Petroleum Corporation 2012 Incentive Compensation Plan Restricted Stock Award Agreement, attached hereto as Exhibit F.

Notwithstanding the foregoing, if any payment, or portion thereof, must be delayed to comply with Section 409A of the Code because Executive is a "specified employee" as defined in Section 409A(a)(2)(B)(i) of the Code , the payment, or the portion so delayed, shall be made on the soonest date permissible without triggering the additional tax due under Section 409A of the Code .

Short-Term Incentives. During Executive's continued employment in a senior management position, Executive shall be eligible to receive bonuses I short-term cash incentives in accordance with the Company's or its Affiliate's cash bonus I short-term incentive program(s) for senior management, as such programs may be modified from time to time. For the 2015 calendar year, Executive shall be entitled to a short-term cash bonus determined by the Company as of the Closing Date, under the performance metrics established by the MarkWest Hydrocarbon, Inc. short-term incentive plan and which shall be paid to Executive as soon as practicable following the end of the Partnership's 2015 calendar year, but within the first two weeks of calendar year 2016.

Long-Term Incentives. Except as otherwise provided in this Paragraph 3.d., during Executive's continued employment in a senior management position, Executive shall be eligible to receive long-term incentive grants in the form of equity in accordance with the Company's or its Affiliate's long-term incentive program(s) for senior management, as such programs may be modified from time to time. Executive will not receive a long-term incentive award in calendar year 2016 since a Long Term Incentive Award has been included in the Retention Bonus as set forth in Paragraph 3.b.

e. Change-in-Control Severance Benefits. During Executive's continued employment in a senior management position, Executive shall be entitled to participate in the Marathon Petroleum Corporation Amended and Restated Executive Change in Control Severance Benefits Plan, under terms and conditions established by the Company.

f . Savings and Retirement Plans. In addition to base salary and the bonuses, Executive shall be entitled to participate during Executive's continued employment with the Company in all savings and retirement plans, practices, policies and programs that are from time to time generally available to other similarly-situated, senior executives of the Company or its Affiliates.

Welfare Benefits. During Executive's continued employment with the Company or its Affiliates, Executive and Executive's eligible dependents, as the case may be, shall be eligible for participation in all benefits under welfare benefit plans, practices, policies, and programs provided by the Company or its Affiliates generally available to other similarly-situated, senior executives of the Company or its Affiliates .


h.	Fringe Benefits / Perquisites. During Executive's continued employment with the Company or its Affiliates in a senior management position, Executive shall be entitled to all fringe benefits that are from time to time generally available to other similarly-situated, senior executives of the Company or its Affiliates.


i.	Vacation. Executive shall be entitled to the same amount of vacation as Executive received under the MarkWest Hydrocarbon, Inc. vacation plan immediately prior to the Closing Date or such vacation time which is provided for similarly situated executives at the Company or its Affiliates under the Company's or its Affiliate's vacation policy, whichever is greater.

2.5 months following the year in which they were incurred.


k.	Officers and Directors Liability Insurance; Indemnification. Executive shall receive coverage under the Company's and its Affiliates' indemnification and directors and officers liability policies to the same extent that it provides such coverage to similarly-situated, senior executives of the Company and its Affiliates.


l.	Crediting of Prior Service. For the purpose of determining eligibility for Company and Affiliate compensation and benefits, vacation accruals, and vesting in savings and retirement plans, Executive shall be credited for any past service that was recognized by MarkWest Hydrocarbon, Inc.


4.	Termination of Employment.

Executive's continued employment with the Company and its Affiliates shall be "at will," meaning that Executive may resign for any reason without any resulting liability to the Company or its Affiliates, and the Company may terminate (or cause the Executive's employer to terminate) Executive's employment for any reason, or no reason, with or without cause, without any resulting liability to Executive, except as expressly provided in this Retention Agreement.


b.	In addition to any amounts or benefits payable under this Retention Agreement, Executive shall, except as otherwise specifically provided herein, be entitled to any payments or benefits provided under the terms of any plan, policy or program of the Company or its Affiliates in which Executive participates or as otherwise required by applicable law.

Restrictive Covenants. Executive acknowledges and agrees that the undertakings, covenants and agreements set forth in Section 7 of the Prior Agreement shall survive and are incorporated by reference into this Retention Agreement. For these purposes, the "Term" shall be mean Executive's continued employment with the Company or its Affiliates under this Retention Agreement; the term "Board" shall mean the Company;

the term "Company" shall mean the Company, as herein defined; and the term "MarkWest Parties" shall mean the Company and its Affiliates.


6.	Miscellaneous.


a.	The Company may assign its rights and obligations under this Retention Agreement to any Affiliate. The Company may also assign it rights and obligations under this Retention Agreement to any successor entity which acquired all or substantially all of the assets of the Company, by merger or otherwise.


b.	This Retention Agreement shall be governed, construed, interpreted and enforced in accordance with the substantive laws of the state of Ohio, without reference to the principles of conflicts of law of Ohio or any other jurisdiction, and where applicable, the laws of the United States.

It is the intention of the Parties that payments or benefits payable under this Retention Agreement not be subject to the additional tax imposed pursuant to Section 409A of the Code, and the provisions of this Retention Agreement shall be construed and administered in accordance with such intent. To the extent such potential payments or benefits could become subject to Section 409A of the Code, the Parties shall cooperate to amend this Retention Agreement with the intent of giving Executive the economic benefits described herein in a manner that does not result in such tax being imposed. If the Parties are unable to agree on a mutually acceptable amendment, the Company may, without Executive's consent and in such manner as it reasonably deems appropriate or desirable, amend or modify this Retention Agreement or delay the payment of any amounts hereunder to the minimum extent necessary to meet the requirements of Section 409A of the Code. To the extent required by Section 409A of the Code, if Executive is required to execute a release of claims as a condition to receipt of any payments or benefits under this Retention Agreement, and the period during which Executive has to execute such release spans two calendar years, such payments and benefits shall be paid (or shall commence) in the second calendar year . The Company makes no representations or warranties as to whether this Retention Agreement (or the Prior Agreement) complies with or is exempt from Section 409A of the Code.

The terms of this Retention Agreement are intended by Executive and the Company to be the final expression of the Parties agreement with respect to matters addressed herein and may not be contradicted by evidence of any prior or contemporaneous agreement, except as noted herein. For purposes of clarification, nothing in this Retention Agreement shall negate the obligations to Executive under Section 6 of the Prior Agreement with respect to payments Executive receives or is entitled to receive under Paragraph 3.b.i of this Retention Agreement and accelerated vesting of equity awards under any MarkWest Hydrocarbon, Inc. or MarkWest Energy Partners, L.P . equity plan or under Section 3(c)(ii) of the Prior Agreement, but there shall be no obligations to

Executive under Section 6 of the Prior Agreement with respect to any other payments contemplated under this Retention Agreement.

e .

This Retention Agreement supersedes all prior agreements between the Parties, and between MarkWest Hydrocarbon , Inc. (or an Affiliate thereof) and Executive , concerning the subject matter hereof (including, but not limited to, salary, bonuses, equity awards, deferred compensation , and severance benefits (cash or noncash)), and including, but not limited to, that certain Retention Agreement dated as of August 5, 2015 (which agreement is hereby rescinded by the Parties) and t he Prior Agreement (i.e., Executive's Employment Agreement, dated September 5, 2007), except to the extent expressly provided herein .

f .

This Retention Agreement may not be modified, amended, or terminated except by an instrument in writing, signed by Executive and a duly authorized officer of the Company except in the case of a cancellation of the Merger in which case this Retention Agreement terminates without any required action on behalf of the Executive or the Company. By an instrument in writing similarly executed, Executive or a duly authorized officer of the Company may waive compliance by the other Party or Parties with any provision of this Retention Agreement that such other party was or is obligated to comply with or perfo rm, pro vi d ed , however, that such waiver shall not operate as a waiver of , or estoppel with respect to, any other subsequent failure . No failure to exercise and no delay in exercising a ny righ t , remedy, or power hereunder preclude any other or further exercise of any other right, remedy, or power provided herein or by law or in equity .


g.	This Retention Agreement may be executed in one or more counterparts, each of which shall be deemed to be an original but all of which together will constitute one and the same instrument.

IN WITNESS WHEREOF, this Retention Agreement has been executed to be effective as of the date and year first written above.



MARATHON PETROLEUM COMPANY LP

By	/s/ Gary R. Heminger
	Name:	Gary R. Heminger
	Title:	President and Chief Executive Officer of Marathon Petroleum Corporation


	EXECUTIVE
	/s/ John C. Mollenkopf
	John C. Mollenkopf

[Signature Page to Retention Agreement ]

EXHIBIT A

EMPL O YME N T AGREE M ENT

TH I S EMPL O YME N T AGREEMENT (the " Agreement ”) is made and entered into as of this 5 ^th day of September 2007 by and between MarkWest Hydrocarbon, Inc., a Delaware corporation, having its principal executive offices in Denver, Colorado (the " Company ”) and John C. Mollenkopf, residing in Littleton, Colorado (the " Executive ").

WHEREAS, the Company derives its revenue and value through its natural gas liquids and gas marketing activities and through its ownership in MarkWest Energy Partners, L.P. (the " Partnership ”), a publicly traded Delaware master limited partnership engaged in the gathering , transportation and processing of natural gas, the transportation and fractionation and storage of NGLs, and the gathering and transportation of crude oil;

WHEREAS, the Company's ownership interest in the Partnership consists of ownership of an approximately 17% limited partner interest in MarkWest Energy Partners, L.P ., and ownership of approximately 89.7% of MarkWest Energy GP, L.L.C. (the " GP" ), the Partnership's general partner;

WHEREAS, the Company and GP have entered into a services agreement (the " Services Agreement ") pursuant to which the Company acts in a management capacity providing day-to day operational, business and asset management, accounting, information services, personnel , and related administrative services to the Partnership;

WHEREAS, the Executive is currently serving as Senior Vice President and Chief Operations Officer of the Company, and in such capacity provides services to or on behalf of the Company and its affiliates, and to the Partnership and its affiliates pursuant to the Services Agreement; and

WHEREAS, the Company and the Executive mutually desire to formalize the employment arrangement of the Executive and to agree upon the terms of the Executive's employment as the Senior Vice President and Chief Operations Officer of the Company and, in addition, to agree as to certain benefits of said employment.

N OW, TH EREF O RE, in consideration of the mutual promises and agreements set forth below, the Company and the Executive hereby agree as follows:

1. TERM OF EMPLOYMEN T : Subject to the terms of this Agreement, the Company hereby continues the employment of the Executive, and the Executive hereby accepts such continuing employment, effective September 5, 2007 (the " Effective Date" ), for a period of three years, subject to earlier termination as provided in Paragraph 4, herein (the "Term"); provided, however, that the Term will automatically be extended by twelve months on the third anniversary of the Effective Date and on each anniversary of the Effective Date thereafter, unless one party to this Agreement provides written notice of non-renewal to the other party at least 30 days prior to the effective date of such automatic extension. The consequences of termination of employment to each party are as set forth in this Agreement . Portions of this Agreement that by their terms provide or imply that they survive the end of the Term shall survive the end of the Term.


2.	POS I T I O N A ND DUTI E S:

a. Position: During the Term, the Executive shall serve as Senior Vice President and Chief Operations Officer of the Company and shall have such duties, responsibilities, and authority as are customarily required of and given to the Senior Vice President and Chief Operations Officer of a public mid-stream energy company. The Executive shall report directly to the Company's Chief Executive Officer and shall perform his or her duties and responsibilities primarily at the Company's offices in Denver, Colorado.

b. Commitment of the Executive: During the Term, the Executive shall devote substantially Executive's full business time, energy, and ability to the business of the Company, the Partnership, and their respective affiliates. As used in this Agreement, the term " Affiliate" means, with respect to any entity, any other entity that directly or indirectly controls, is controlled by, or is under common control with such first entity.

c. Othe r Positions and Services: The Executive may (i) with the prior written approval of the Company's Board of Directors (the " Board ”), which approval shall not be unreasonably withheld or delayed, serve as a director or trustee of other for profit corporations or businesses, provided, that if a directorship is approved and the Board later determines (A) that the directorship would violate Paragraph 7 of this Agreement, or (B) that that the Board no longer approves of the directorship, which approval shall not be unreasonably withdrawn, it shall notify the Executive in writing and the Executive shall resign such directorship within a reasonable period of time, (ii) serve on civic or charitable boards or committees, and (iii) deliver lectures, fulfill speaking engagements, or teach at educational institutions (and retain any fees therefrom) provided, however , that the Executive may not engage in any of the activities described in this Paragraph 2(c) to the extent such activities interfere materially with the performance of the Executive's duties and responsibilities to the Company.

d. I nvestme nt s: Except as may otherwise be permitted by this Agreement, without the prior express authorization of the Board, the Executive shall not, during the Term, directly or indirectly render services of a business, professional, or commercial nature to any other person or firm, whether for compensation or otherwise. Notwithstanding the foregoing, the Executive may be an investor, shareholder , joint venturer, or partner in any such business (hereinafter referred to as " Investor "); provided, that Executive's status as an Investor shall not (i) pose a conflict of interest with regard to Executive's employment, (ii) require the Executive's active involvement in the management or operation of such Investment (recognizing that the Executive shall be permitted to monitor and oversee the Investment), or (iii) interfere materially with the performance of the Executive's duties and obligations hereunder. For the purposes of clause (i) of the preceding sentence, the Executive shall not be deemed to be subject to a conflict of interest merely by reason of the ownership of less than five percent (5%) of (i) the outstanding stock of any entity whose stock is traded on an established stock exchange or on the National Association of Securities Dealers Automated Quotation System, or (ii) the outstanding stock, partnership interests or other form of equity interest of any venture fund, investment pool or similar investment vehicle .

e. No Conflict: The Executive represents and warrants that, to the best of Executive's knowledge after the review of Executive's personal files, he has the full right and authority to enter into this Agreement and to render the services as required under this Agreement, and that by signing this Agreement and rendering such services he is not breaching any contract or legal obligation he owes to any third party.

3. COMPENSATION AND BENEFITS: During the Term, while the Executive is employed by the Company, the Company shall compensate the Executive for his or her services as set forth in this Paragraph 3. The Executive recognizes that during the Term of the Agreement, the Company reserves the right to change from time to time the terms and benefits of any retirement, welfare or fringe benefit plan of the Company, including the right to change any service provider, so long as such changes are also applicable generally to all executives of the Company.

a. Salary : During the Term, the Company shall pay the Executive a base salary at an annual rate of $275,000.00 (the " Base Salary" ). Base Salary shall be earned and shall be payable in periodic installments in accordance with the Company's payroll practices. Amounts payable shall be reduced by standard withholding and other authorized deductions. The Compensation Committee of the Board (the " Compensation Committee' ') will review the Executive's salary at least annually and may adjust the Executive's Base Salary in its sole discretion. Executive's salary as so adjusted shall thereafter be treated as Executive's Base Salary hereunder.

b. Cash Bonus I Short-Term Incentives : The Executive shall be eligible to receive bonuses/short-term cash incentives in accordance with the Company's cash bonus/short term incentive program(s) for senior management, as such program(s) may be modified from time to time. All bonuses/short-term cash incentives shall be paid in a manner that complies with the requirements of Section 409A of the Internal Revenue Code of 1986, as amended (the " Code ").


c.	Equity Compensation Programs :

(i) General. The Executive shall be entitled to participate in all equity compensation programs sponsored by the Company, the Partnership, or their Affiliates (the "Equity Plans"). The size and terms of any grants to be made to Executive shall be established by the Compensation Committee, or the Compensation Committee of the Partnership, in their sole discretion.

(ii) Change of Control. All grants made under the Equity Plans (including those made prior to the effective date of this Agreement) shall vest in full immediately prior to the occurrence of a Change of Control. For purposes of this Agreement, a Change of Control shall mean the first to occur of:

(A) any "person" (as defined in Section 13(d) and 14(d) of the Securities Exchange Act of 1934, as amended (the " Exchange Act" )) other than (1) the Company or any Affiliate of the Company as of the date of this Agreement, (2) any employee benefit plan of the Company or any Affiliate of the Company, or (3) any person or entity organized, appointed or established by the Company for or pursuant to the terms of any such plan which acquires beneficial ownership of voting securities of the Company, is or becomes the beneficial

owner, directly or indirectly, of securities of the Company representing 50% or more of the combined voting power of the Company's then outstanding securities.

(B) the individual directors of the Board on the effective date of this Agreement (" Incumbent Directors' ') cease to constitute at least two-thirds of the Board within any three (3) year period. For purposes of this paragraph, any new director whose election by the Board or nomination for election by the Company's stockholders was approved by a vote of at least two-thirds of the Incumbent Directors shall be considered an Incumbent Director. However, no director whose initial election to the Board occurs as a result of an actual or threatened election contest with respect to the election or removal of director or other actual or threatened solicitation of proxies or consents by or on behalf or a person other than the Board shall be considered a Incumbent Director;

(C) consummation of a reorganization, merger or consolidation of the Company (a " Business Combination" ), in each case, unless, following such Business Combination, the individuals and entities who were the beneficial owners of outstanding voting securities of the C ompany immediately prior to such Business Combination beneficiall y own, by reason of such ownership of the Company's voting securities immediately before the Business Combination, directly or indirectly, more than 50% of the combined voting power of the then outstanding voting securities entitled to vote generally in the election of directors of the company resulting from such Business Combination (including, without limitation, a company which as a result of such transaction owns the Company or all or substantially all of the Company's assets either directly or through one or more subsidiaries) in substantially the same proportions as their ownership of the outstanding voting securities of the Company immediately prior to such Business Combination; or

(D) approval by the stockholders of the Company of a complete liquidation or dissolution of the Company.

(E) any sale, lease, exchange, or other transfer or disposition of all or substantially all of the assets of the Partnership or the GP;

(G) the general partner of the Partnership (whether it be the GP or another entity) ceases to be an Affiliate of the Company.

e. Welfare Benefit Plans: The Executive and Executive's family, as the case may be, shall be eligible to participate in and shall receive all benefits under the Company's welfare benefit plans and programs applicable generally to other senior executives of the Company (collectively, as amended from time to time, the " Company Plans" ), in accordance with the terms of the Company Plans.

f. Vacation and Sick Leave: Executive shall be entitled to paid vacation, sick leave, and paid time off in accordance with the plans, policies, and programs in effect generally with respect to other senior executives of the Company, including the limitations, if any, on the carry-over of accrued but unused time.

g. Expenses: The Company shall reimburse the Executive for reasonable expenses for cellular telephone usage, entertainment, travel, meals, lodging, and similar items incurred in the conduct of the Company's business. Such expenses shall be reimbursed in accordance with the Company's expense reimbursement policies and guidelines.

h. Fringe Benefits and Perquisites. Executive and Executive's family, as the case may be, shall be eligible for all other fringe benefits or perquisites offered generally to senior executives of the Company (and their families, as applicable).

i. Officers and Directors Liability Insurance; Indemnification: During Executive's employment with the Company and thereafter so long as Executive may have liability arising out of Executive's service as an officer or director of the Company or any Affiliate, the Company agrees to continue and maintain a director's and officer's liability insurance policy (" D&O Insurance ”) covering Executive in an amount that is reasonable and customary based on the size and business activities of the Company, the Partnership, and their Affiliates, and the authorities, power, responsibilities, and duties of Executive. To the fullest extent permitted by the indemnification provisions of the Company's governing instruments in effect as of the date of this Agreement and the indemnification provisions of the governing laws of the jurisdiction of the Company's formation in effect from time to time (collectively, the "Indemnification Provisions"), and in each case subject to the conditions thereof, the Company shall (i) indemnify the Executive, as a director (if applicable) and officer of the Company or an Affiliate of the Company or a trustee or fiduciary of an employee benefit plan of the Company or an Affiliate of the Company, or, if the Executive shall be serving in such capacity at the Company's request, as a director or officer of any other entity (other than an Affiliate of the Company) or as a trustee or fiduciary of an employee benefit plan not sponsored by the Company or an Affiliate of the Company, against all liabilities and reasonable expenses that may be incurred by the Executive in any threatened, pending, or completed action, suit or proceeding, whether civil, criminal or administrative, or investigative and whether formal or informal, because the Executive is or was a director or officer of the Company or any Affiliate, a director

or officer of such other entity or a trustee or fiduciary of such employee benefit plan, and against which the Executive may be indemnified by the Company, and (ii) pay for or advance to Executive the reasonabl e expenses incurred by the Executive in the defense of any proceeding to which the Executive is a party because the Executive is or was a director or officer of the Company or an Affiliate, a director or officer of such other entity or a trustee or fiduciary of such employee benefit plan. The rights of the Executive under the Indemnification Provisions shall survive the termination of the employment of the Executive by the Company.

4. TERMINATION : The Executive's employment with the Company during the Term may be terminated by the Company or the Executive pursuant to this Paragraph 4, subject to the provisions of Paragraph 5:

a. Death or Disability: If the Executive has a Disability (as defined below), the Company may give to the Executive written notice of its intention to terminate the Executive's employment. In such event, the Executive's employment with the Company shall terminate effective on the 30th day after receipt of such notice by the Executive, provided that, within the 30-day period after such receipt, the Executive shall not have returned to full-time performance of the Executive's material duties. For purposes of this Agreement, "Disability" shall mean any physical or mental condition which prevents the Executive, for a period of 90 consecutive days, from performing and carrying out Executive's material duties and responsibilities with the Company, as determined under the Company's long-term disability plan. The Executive's employment hereunder shall terminate automatically upon the Executive's death.

b. Cause: The Company may terminate this Agreement immediately upon written notice to the Executive if, after the Executive is given an opportunity to be heard by the Board and to present evidence on Executive's behalf, a formal determination is made by a majority of the directors on the Board and at least two-thirds of the Board's non-employee directors, that the Executive should be terminated for "Cause". Any one or more of the following events shall constitute "Cause":

(i) conviction of (or pleading nolo contendere to) a felony that is injurious to the business or reputation of the Company, the Partnership, or their Affiliates;

(ii) engaging in intentional wrongdoing (including without limitation, theft, fraud, embezzlement, or willful misappropriation of the funds or property of the Company, the Partnership, or their Affiliates) , or failure by Executive to substantially adhere to the Company work rules, policies or procedures, that is injurious to the business or reputation of the Company, the Partnership, or their Affiliates, or breach of fiduciary duties for enrichment of the Executive;

(iii) illegal or prohibited treatment of or relations with any employee, agent or consultant of the Company, the Partnership, or their Affiliates or of any person with whom the Company, the Partnership, or their Affiliates have a business relationship, in the form of illegal or prohibited discrimination, harassment, abuse, assault or other actions of a similar nature;

(iv) Executive has failed to perform substantially Executive's material duties as contemplated by Paragraph 2 above (other than such failure resulting from incapacity due to physical or mental illness), which, for avoidance of doubt, shall include Executive's insubordination to his or her direct or indirect reports or to the Board, after (i) a written demand for corrected performance is delivered to Executive by the Board which identifies specifically the manners in which the Board believes Executive has not performed substantially Executive's material duties, and (ii) Executive's failure to cure such items identified in the Board's letter within 30 days.

(v) any material breach of Executive's obligations under this Agreement including, but not limited to, a breach of Executive's obligations under Paragraph 7; provided, however, that in the event such breach is curable and is actually cured within ten (10) days after written notice detailing the nature and facts of such breach is delivered to Executive, the breach shall not be considered "Cause" for Executive's termination.

(vi) engaging in actions or behavior that bring Executive into public hatred, disrepute, scorn, or ridicule, or shock, insult, or offend the community or public morals or decency, in each case resulting in injury to the business or reputation of the Company or inhibiting the ability of Executive to effectively represent publicly the Company, the Partnership, or their Affiliates.

c. Other than Death or Disability or Cause: The Company may terminate the Executive's employment upon thirty (30) days written notice to the Executive at any time and for any reason other than Death, Disability, or Cause.

d. Termination by Executive : The Executive may terminate Executive's employment upon thirty (30) days written notice to the Company at any time and for any reason.


5.	OBLIGATIONS OF THE COMPANY AND THE EXECUTIVE UPON

TERMINATION :

(ii) the payments and benefits provided in Paragraph 5(g),

(iii) payment to the Executive of a lump sum equal to (A) 24 months of the Executive’s then current Base Salary, (B) two (2) times the average annual bonus earned by the Executive for the two most recently completed fiscal years, and (C) a pro-rata portion of the target amount of the annual bonus for the fiscal year of termination, calculated based on the portion of such fiscal year the Executive is employed. The lump sum payment shall be made within thirty (30) days

of termination or, if the payment, or any portion thereof, must be delayed to comply with Code Section 409A because the individual is a “specified employee” as defined in Code Section 409(a)(2)(B)(i), the payment, or the portion so delayed, shall be made on the soonest date permissible without triggering the additional tax due under Code Section 409A;

(iv) subject to Paragraph 3(c), the accelerated vesting of each stock option or unit option, phantom unit, restricted stock or restricted unit, or o ther equity incentive award granted under the Equity Plans (or portion thereof) that would have otherwise vested solely upon the Executive remaining in the continuous employment of the Company for a period of twelve (12) months after the date of termination, and

(v) payment of all premiums for properly elected group health plan continuation coverage for Executive and his or her spouse and dependents pursuant to the Consolidated Omnibus Budget Reconciliation Act of 1985 (" COBRA" ) for the lesser of (A) the number of months of Base Salary to be paid to Executive under subparagraph (iii)( A), above, or (B) the duration of such COBRA coverage. All such premiums shall be paid on the first day of the month. In addition, in the event that payment of such premiums is taxable to executive, the Company shall pay to Executive an amount, as and when such premiums are paid, such that after taking into account all taxes due on the premiums and on the additional payment, the Executive will be in the same economic position as he would have been in had such premiums been non taxable.

The Company shall be obligated to make the foregoing payments and to provide the foregoing benefits upon the Executive (or, if applicable, the Executive's legal representative) and the Company signing a mutual release (the " Release" ) of all claims (including claims by, on behalf of, or against the Partnership, any Affiliates of the Partnership or the Company, and their respective directors, agents, employees, and assigns) in a form provided by the Company, which release shall, if applicable, give the Executive appropriate notifications under the Age Discrimination in Employment Act, as amended by the Older Workers Benefit Protection Act, and which shall not affect (x) rights under COBRA and (y) conversion rights under any applicable life insurance policies.

b. Termination for Cause : If the Executive's employment is terminated by the Company for Cause, the Term shall terminate without further obligations to the Executive under this Agreement after the date of such termination, other than for (i) payment of the Accrued Obligations, and (ii) the payments and benefits provided in Paragraph 5(h).

c. Other than Dea t h or Disability or Cause : If the Company terminates the Executive's employment during the Term for any reason other than Death, Disability, or Cause, the Term shall end on the date of such termination and the Executive shall, upon signing of a Release, be entitled to the payments, benefits and other compensation provided above in Paragraph 5(a).

d. Voluntarv Termination by Executive : lf the Executive terminates his or her employment without Good Reason, as defined below, the Term shall end and the Company shall provide to Executive:

(i) the Accrued Obligations


(ii)	the payments and benefits provided in Paragraph 5(h)

(A) a lump sum payment equal to three (3) months of the Executive's then current Base Salary, which amount shall be paid within ten (1 0) days of termination or, if the payment, or any portion thereof, must be delayed to comply with Code Section 409A because the individual is a "specified employee" as defined in Code Section 409A(a)(2)(B)(i), the payment, or the portion so delayed, shall be made on the soonest date permissible without triggering the additional tax due under Code Section 409A;

(B) payment of all premiums for properly elected COBRA coverage for Executive and his or her spouse and dependents for the lesser of(A) the number of months of Base Salary to be paid to Executive under subsection (d)(iii)(A), above, or (B) the duration of such COBRA coverage.


e.	Termination by Executive for Good Reason :

(i) In General. If the Executive terminates his or her employment for Good Reason, as defined below, the Term shall terminate on the date of such termination and the Executive shall, upon signing a Release, be entitled to the payments, benefits and other compensation provided above in Paragraph 5(a).

(ii) " Good Reason ”. For purposes of this Agreement, the Executive's termination of employment with the Company shall be on account of "Good Reason" if it occurs for any of the following reasons: (A) any failure by the Company to comply with any of the provisions of Paragraph 3 of this Agreement, including but not limited to the failure by the Company to pay to the Executive any portion of his or her compensation in violation of the provisions of Paragraph 3, other than an isolated, insubstantial and inadvertent failure not occurring in bad faith and which is remedied by the Company promptly after receipt of notice thereof given by the Executive; (B) a material diminution in Base Salary or bonus opportunity not related to performance or market conditions, other than which is remedied by the Company within thirty (30) days after receipt of notice thereof given by the Executive; (C) a material diminution in responsibility or authority other than which is remedied by the Company within thirty (30) days after receipt of notice thereof given by the Executive; (D) the forced relocation of Executive's principal place of employment to a location more than 50 miles from the Executive's then-current principal place of employment; or (E) the occurrence of a Change of Control, provided that Executive voluntarily terminates his or her employment within twelve

(12) months of the Change of Control.

upon signing a Release, be entitled to the payments, benefits, and other compensation provided in Paragraph 5(a) above , and (ii) if such notice was given by the Executive, the termination shall be deemed a "Voluntary Termination by Executive" and Executive shall, upon signing a Release, be entitled to the payments, benefits, and other compensation provided in Paragraph 5(d) above.


g.	General Partner Membership Interest:

(i) Limited Application. The provisions of Paragraph 5(g)(ii) below shall a pp ly solely in the event that the Company and the Partnership announce formally to the public (whether through a press release or the filing of a current report on Form 8-K) that they no longer intend to pursue the proposed acquisition/business combination/restructuring transaction that was announced formally to the public on February 21, 2007.

(ii) Repurchase of General Partner Membership Interest .Executive is hereby granted the option to elect at any time, by written notice to the Company, to cause the Company to purchase all, but not less than all of Executive's Class B membership interest in MarkWest Energy GP, L.L.C. at the price established pursuant to the formula set forth in the GP LLC Agreement as of the delivery date of Executive's election notice (" Election Date" ). If the Executive makes such election, the Company shall purchase the Executive's Class B membership interest within thirty (30) days following the Election Date, such purchase price to be paid, at Company's election, either (i) in full in cash by wire transfer of immediately available funds; or (ii) by a combination of cash and of common units of the Partnership, with a value for the common units as of the Election Date based on the closing price of the Partnership's common units for the twenty trading days preceding the Election Date, with the combination of cash and Partnership common units being equal to the price established pursuant to the formula set forth in the GP LLC Agreement , provided that the value of the Partnership common units cannot comprise more than 50% of the purchase price established pursuant to the formula set forth in the GP LLC Agreement.

h. Exclusive Remedy: Except for the payments and benefits provided in this Paragraph 5, and under Paragraph 3(c), the Executive acknowledges and agrees that upon termination of the Term, he shall have no other claims against, and shall be entitled to no other payments or benefits from the Company under this Agreement or pursuant to the Company's policies and plans, other than (A) the Executive's rights under COBRA, (B) any conversion rights under any applicable l ife insurance policies, (C) payment of any amounts due pursuant to the terms of any equity-based plan of the Company or any welfare or retirement plan of the Company as of the date of termination or which by their specific terms extend beyond such date of termination, and (D) rights with respect to D&O Insurance and/or the Indemnification Provisions. The Executive and the Company have agreed that Executive will not participate in either the MarkWest Hydrocarbon Inc. 1997 Severance Plan or the MarkWest Hydrocarbon, Inc. 2007 Severance Plan. In lieu of participation in such Severance Plans, the parties have agreed that the Executive will receive certain other payments and benefits as set forth in this Agreement. In no event shall the Executive be obligated to seek other employment or take any other action by way of mitigation of the amounts payable to the Executive under any of the provisions of this Agreement and such amounts shall not be reduced whether or not the Executive obtains other employment.

i. Resignations: On and as of the date that the employment of the Executive by the Company shall terminate for any reason, the Executive shall, if applicable, resign from his or her position as a director and officer of the Company or the Partnership, resign from all other positions he or she holds as a director, officer or employee of any subsidiary or Affiliate of the Company or the Partnership, and resign as a named fiduciary of any employee benefit plans sponsored by the Company or the Partnership or their subsidiaries or Affiliates.

6. 280G Provisions.

a. Determination; Efficient Gross-Up : If it is determined that any payment or benefit provided to or for the benefit of the Executive (a " Payment' '), whether paid or payable or distributed or distributable pursuant to the terms of this Agreement or otherwise, would be subject to the excise tax imposed by Code section 4999 or any interest or penalties with respect to such excise tax (such exc i se tax together with any such interest and penalties, shall be referred to as the "Excise Tax "), then a calculation shall first be made under which such payments or benefits provided to the Executive are reduced to the extent necessary so that no portion thereof shall be subject to the Excise Tax (the "4999 Limit"). The Company shall then compare (a) the Executive's Net After-Tax Benefit (as defined below) assuming application of the 4999 Limit with (b) the Executive's Net After-Tax Benefit without application of the 4999 Limit. "Net After-Tax Benefit" shall mean the sum of (i) all payments that Executive receives or is entitled to receive that are contingent on a change in the ownership or effective control of the Company or in the ownership of a substantial portion of the assets of the Company within the meaning of Code section 280G(b)(2), less (ii) the amount of federal, state, local, employment, and Excise Tax (if any) imposed with respect to such payments. In the event (a) is greater than (b), Executive shall receive Payments solely up to the 4999 Limit and Executive shall choose which payments shall be reduced and the amount of the reduction of each payment. In the event (b) is greater than (a), then the Executive shall be entitled to receive all such Payments along with an additional payment (a " Gross-Up Payment" ) in an amount such that after payment by the Executive of all taxes (including any interest or penalties imposed with respect to such taxes), including, without limitation. any income taxes (and any interest and penalties imposed with respect thereto) and Excise Tax imposed upon the Gross-Up Payment, the Executive retains an amount of the Gross-Up Payment equal to the Excise Tax imposed upon the Payments.

b. Calculations : All determinations required under this Paragraph 6, including the determination of whether a Payment is subject to the Excise Tax or the amount of any required Gross-Up Payment, shall be made by tax counsel, a nationally recognized certified public accounting firm not serving as auditor for the Company, or another tax professional with experience in such calculations, as selected by the Company and reasonably acceptable to the Executive (the " Tax Professional "). The Tax Professional shall provide detailed supporting calculations for its determinations both to the Company and the Executive within fifteen days of receipt of any Payment, or such sooner period as may be requested by the Company. All costs relating to the Tax Professional shall be borne exclusively by the Company. Subject to Paragraph 6(d), below, any determination by the Tax Professional shall be binding upon the Company and the Executive.

Payments is remitted to the Internal Revenue Service. As a result of the uncertainty in the application of Section 4999 of the Code at the time of the initial determination by the Tax Professional hereunder, it is possible that a Gross-Up Payment which will not have been made by the Company should have been made (" Underpayment" ). In the event that the Company exhausts its remedies pursuant to Paragraph 6(d) and the Executive thereafter is required to make a payment of any Excise Tax, the Tax Professional shall determine the amount of the Underpayment that has occurred and any such Underpayment shall be promptly paid by the Company to or for the benefit of the Executive, but in no event shall such payment be made later than the end of Executive's tax year following the tax year in which the Excise Tax is remitted to the Internal Revenue Service.

d. Tax Controversy : The Executive shall notify the Company in writing of any claim by the Internal Revenue Service that, if successful, would require the payment by the Company of an Underpayment Such notification shall be given as soon as practicable but no later than ten business days after the Executive is informed in writing of such claim and shall apprise the Company of the nature of such claim and the date on which such claim is requested to be paid. The Executive shall not pay such claim prior to the expiration of the thirty-day period following the date on which it gives such notice to the Company (or such shorter period ending on the date that any payment of taxes with respect to such claim is due). If the Company notifies the Executive in writing prior to the expiration of such period that it desires to contest such claim, the Executive shall:

(i) give the Company any information reasonably requested by the Company relating to such claim,

(ii) take such action in connection with contesting such claim as the Company shall reasonabl y req uest in writing from time to time, including, without limitation, accepting legal representation with respect to such claim by an attorney reasonably selected by the Company,

(iii) cooperate with the Company in good faith in order effectively to contest such claim, and

(iv) permit the Company to participate in any proceedings relating to such claim;

advance the amount of such payment to the Executive, on an interest-free basis and shall indemnify and hold the Executive harmless, on an after-tax basis, from any Excise Tax or income tax (including interest or penalties with respect thereto) imposed with respect to such advance or with respect to any imputed income with respect to such advance; and further provided that any extension of the statute of limitations relating to payment of taxes for the taxable year of the Executive with respect to which such contested amount is claimed to be due is limited solely to such contested amount. Furthermore, the Company's control of the contest shall be limited to issues with respect to which a Gross-Up Payment would be payable hereunder and the Executive shall be entitled to settle or contest, as the case may be, any other issue raised by the Internal Revenue Service or any other taxing authority.

e. Refunds; Etc.: If, after the receipt by the Executive of an amount advanced by the Company pursuant to Section 6(d), the Executive becomes entitled to receive any refund with respect to such claim, the Executive shall (subject to the Company's complying with the requirements of Section 6(d)) promptly pay to the Company the amount of such refund (together with any interest paid or credited thereon after taxes applicable thereto). If, after the receipt by the Executive of an amount advanced by the Company pursuant to Section 6(d), a determination is made that the Executive shall not be entitled to any refund with respect to such claim and the Company does not notify the Executive in writing of its intent to contest such denial of refund prior to the expiration of thirty days after such determination, then such advance shall be forgiven and shall not be required to be repaid and the amount of such advance shall offset, to the extent thereof, the amount of Underpayment required to be paid.

7. CONFIDENTIAL INFORMATION; NON-COMPETITION, NON- SOLICITATION:

a. Confidential Information: Except as permitted or directed by the Board, during the Term or at any time thereafter, Executive shall not divulge, furnish, make accessible to anyone, lay claim to, attempt to lay claim to or use, or attempt to use, in any way (other than in the ordinary course of the business of the Company) any confidential or secret knowledge or information of the Company, the Partnership, or their respective Affiliates (collectively the "MarkWest Parties") that Executive has acquired or become acquainted with or will acquire or become acquainted with during the period of Executive's employment by the Company, whether developed by himself or by others, concerning any pricing information, trade secrets, confidential or secret plans or material (whether or not patented or patentable) directly or indirectly useful in any aspect of the business of the MarkWest Parties, any customer or dealer lists of the MarkWest Parties, any confidential or secret development of the MarkWest Parties, or any other confidential information or secret aspects of the business of the MarkWest Parties (collectively, " Confidential Information" ). Executive acknowledges that the Confidential Information constitutes a unique and valuable asset of the MarkWest Parties and represents a substantial investment of time and expense by the MarkWest Parties, and that any disclosure or other use of the Confidential Information other than for the sole benefit of the MarkWest Parties would be wrongful and would cause irreparable harm to the MarkWest Parties. Both during and after the Term, Executive shall refrain from any acts or omissions that would reduce the value of the Confidential Information. The foregoing obligations of confidentiality shall not apply to any knowledge or information that is now published or that subsequently becomes generally publicly known in the form in which it was obtained from the MarkWest Parties, other than as a direct or indirect result of the breach of this Agreement by Executive; is lawfully obtained by Executive from a third party, provided that Recipient did not have actual knowledge that such third party

was restricted or prohibited from disclosing such information to Executive; or was independently developed by Executive, without use of any information obtained from Company. At the time of the termination of Executive's employment, or at such other time as the Company may request, Employee shall return all memoranda, notes, plans, records, computer tapes and software and other documents and data (and copies thereof) relating to Confidential Information that Executive may then possess or have under his or her control.

b. Non-competition; Non-solicitation : Executive understands and agrees that, in addition to Employee's exposure to Confidential Information, Executive may, in his or her capacity as an employee, at times meet with the MarkWest Parties' current or prospective customers, suppliers, partners, licensees or other business relations (collectively, " Business Relations" ) on behalf of the MarkWest Parties, and that, as a consequence of using or associating himself with the MarkWest Parties' name, goodwill, and professional reputation, Executive's employment shall place him or her in a position where Executive can develop personal and professional relationships with the MarkWest Parties' current and prospective customers. Executive further acknowledges that, during the course and as a result of Executive's employment, Executive has been or may be provided certain specialized training or know-how . Executive understands and agrees that this goodwill and reputation, as well as Executive's knowledge of Confidential Information and specialized training and know-how, could be used unfairly in competition against the MarkWest Parties. Accordingly, in consideration of the employment of Executive by the Company pursuant to this Agreement, Employee agrees that:

(i) during the time period commencing on the date hereof· and terminating six (6) months after the end of the Term, Executive shall not directly or indirectly, individually or collectively in conjunction with others, engage in activities that compete with the business that the MarkWest Parties is engaged in at the time of the termination of Executive's employment in whatever geographic regions the MarkWest Parties engages in such business a t such time (currently natural gas and refinery off-gas gathering and transportation, natural gas and refinery off-gas processing, off-gas and NGL fractionation, NGL, natural gas and derived products marketing, and related services, conducted in the southern Appalachian region of Kentucky, West Virginia, and southern Ohio, in the southwest and mid-continent regions of Oklahoma, Texas, Louisiana, Mississippi, and New Mexico, on the Gulf Coast, and in western Colorado/eastern Utah area); or

(ii) during the time period commencing on the date hereof and terminating eighteen (18) months after the end of the Term, Executive shall not directly or indirectly through another entity or person (i) induce or attempt to induce any employee of the MarkWest Parties to leave the employ of the MarkWest Parties, (ii) solicit to hire any person who was employed by the MarkWest Parties at any time during the one-year period immediately preceding the termination of Executive's employment with the MarkWest Parties, or (iii) induce or attempt to induce any current or prospective Business Relation of the MarkWest Parties (including, without limitation, any business entity that the MarkWest Parties have contacted in order to make a proposal to enter into a business relationship) to withdraw, curtail or cease doing business with the MarkWest Parties; provided, however, that Executive shall not be in breach of this paragraph in the event that any entity with whom Executive is employed or otherwise affiliated solicits or hires any person so long as Executive is not consulted concerning or otherwise involved, directly or indirectly, in such solicitation and/or hiring (except for involvement in a general administrative or other perfunctory manner), nor shall Executive be in breach of this paragraph in the event that any person applies for or inquires concerning employment in response to any

advertisement or other job posting directed to the public in general, so long as Executive is not consulted concerning or otherwise involved, directly or indirectly, in any aspect of the recruitment, evaluation or hiring of the person(s) in question (except for involvement in a general administrative or other perfunctory manner).

Executive acknowledges that as an executive of a public company he falls within the exception to C.R.S 8-2-113(2)(d), which exempts executive and management personnel and officers from the prohibitions of non-compete provisions. Executive further agrees, during the period for which Executive has continuing obligations under this Paragraph 7(b), to inform any new employer or other person or entity with whom Executive enters into a business relationship, before accepting employment or entering into a business relationship, of the existence of this Agreement and give such employer, person other entity a copy of this Paragraph 7(b).

c. Third-Party Beneficiaries : It is the express intent of the parties that the provisions of this Paragraph 7 may be enforced by any of the MarkWest Parties, and that the protections afforded herein shall inure to such MarkWest Parties as intended third-party beneficiaries.

thereunder. The Company will require any successor (whether direct or indirect, by purchase, merger, consolidation or otherwise) to all or substantially all of the business and/or assets of the Company to assume expressly and agree to perform this Agreement in the same manner and to the same extent that the Company would be required to perform it if no such succession had taken place. As used in this Agreement, "Company" shall mean the Company as herein before defined and any successor to its business and/or assets as aforesaid which assumes and agrees to perform this Agreement by operation of law or otherwise.

9. DISPUTE RESOLUTION : Any claim arising out of or in any way relating to this Agreement or the termination thereof shall be initiated in the federal or state courts for Denver, Colorado and both Executive and the Company (and the MarkWest Parties, as applicable) hereby submit to the jurisdiction of such courts. Each party shall be responsible for the payment of its own attorneys' fees; provided , however, that, the Company shall reimburse the Executive for all reasonable legal fees incurred by Executive for any claim arising out of or in any way relating to events occurring on and after a Change in Control, except any such claim initiated by Executive that is found to be frivolous or vexatious.

10. GOVERNING LAW : The provisions of this Agreement shall be construed in accordance with, and governed by, the laws of the State of Colorado without regard to principles of conflict of laws.

11. SAVINGS CLAUSE : If any provision of this Agreement or the application thereof is held invalid, the invalidity shall not affect other provisions or applications of the Agreement which can be given effect without the invalid provisions or applications and to this end the provisions of this Agreement are declared to be severable.

12. WAIVER OF BREACH : No waiver of any breach of any term or provision of this Agreement shall be construed to be, nor shall be, a waiver of any other breach of this Agreement. No waiver shall be binding unless in writing and signed by the party waiving the breach.

13. MODIFICATION : No provision of this Agreement may be amended, modified, or waived except by written agreement signed by the parties hereto.

14. ASSIGNMENT OF AGREEMENT : The Executive acknowledges that Executive's services are unique and personal. Accordingly, the Executive may not assign Executive's rights or delegate Executive's duties or obligations under this Agreement to any person or entity; provided , however , that payments may be made to the Executive's estate or beneficiaries as expressly set forth herein.

15. ENTIRE AGREEMENT : This Agreement is an integrated document and constitutes and contains the complete understanding and agreement of the parties with respect to the subject matter addressed herein, and supersedes and replaces all prior negotiations and agreements, whether written or oral, concerning the subject matter hereof.

16. CONSTRUCTION : Each party has cooperated in the drafting and preparation of this Agreement. Hence, in any construction to be made of this Agreement, the same shall not be construed against any party on the basis that the party was the drafter . The captions of this Agreement are not part of the provisions and shall have no force or effect.

a. in the case of delivery by overnight service with guaranteed next day delivery, such next day or the day designated for delivery;

b. in the case of certified or registered United States mail, five days after deposit in the United States mail; or

c. in the case of facsimile, the date upon which the transmitting party received confirmation of receipt by facsimile, telephone, or otherwise; and


d.	in the case of personal delivery, when received.

Communications that are to be delivered by the United States mail or by overnight service are to be delivered to the addresses set forth below:


(i)	To the Company:

MarkWest Hydrocarbon, Inc. Attn: General Counsel

1515 Arapahoe Street, Tower 2, Suite 700

Denver, CO 80202


(ii)	To the Executive: John C. Mollenkopf

6205 S. Benton Ct.

Littleton, CO 80123

Each party, by written notice furnished to the other party, may modify the acceptable delivery address, except that notice of change of address shall be effective only upon receipt. In the event that the Company is aware that the Executive is not at the location when notice is being given, notice shall be deemed given when received by the Executive, whether at the aforementioned location or at another location.

18. TAX WITHHOLDING : The Company may withhold from any amounts payable under this Agreement such federal, state, or local taxes as shall be required to be withheld pursuant to any applicable law or regulation.

consult with counsel of Executive's choice, and to negotiate at arm's-length with the Company as to its contents. The Executive and the Company agree that the language used in this Agreement is the language chosen by the parties to express their mutual intent, and that they have entered into this Agreement freely and voluntarily and without pressure or coercion from anyone.

IN WITNESS WHEREOF, the Company and the Executive, intending to be legally bound, have executed this Agreement on the day and year first above written .



MARKWEST HYDROCARBON, INC.

By	/s/ Frank M. Semple
	Name:	Frank M. Semple
	Title:	President and Chief Executive Officer


	EXECUTIVE
	/s/ John C. Mollenkopf
	John C. Mollenkopf