PART I—FINANCIAL INFORMATION

See accompanying notes to condensed consolidated financial statements.

See accompanying notes to condensed consolidated financial statements.

See accompanying notes to condensed consolidated financial statements.

(1) Business and Organization

Antero Midstream Partners LP (the “Partnership”) is a growth-oriented master limited partnership formed by Antero Resources Corporation (“Antero Resources”) to own, operate and develop midstream energy infrastructure primarily to service Antero Resources’ increasing production and completion activity in the Appalachian Basin’s Marcellus Shale and Utica Shale located in West Virginia and Ohio. The Partnership’s assets consist of gathering pipelines, compressor stations, interests in processing and fractionation plants, and water handling and treatment assets, through which the Partnership and its affiliates provide midstream services to Antero Resources under long-term, fixed-fee contracts. The Partnership’s condensed consolidated financial statements as of March 31, 2018 include the accounts of the Partnership and its 100% owned operating subsidiaries: Antero Midstream LLC, Antero Water LLC (“Antero Water”), Antero Treatment LLC (“Antero Treatment”), and Antero Midstream Finance Corporation (“Finance Corp”), all of which are entities under common control.

The Partnership also has a 15% equity interest in the gathering system of Stonewall Gas Gathering LLC (“Stonewall”) and a 50% equity interest in a joint venture to develop processing and fractionation assets (the “Joint Venture”) with MarkWest Energy Partners, L.P. (“MarkWest”). See Note 13—Equity Method Investments.

The Partnership’s financial statements are consolidated with the financial statements of Antero Resources (NYSE: AR), our primary beneficiary, for financial reporting purposes. 

(2) Summary of Significant Accounting Policies

(a) Basis of Presentation

These condensed consolidated financial statements have been prepared pursuant to the rules and regulations of the U.S. Securities and Exchange Commission (the “SEC”) applicable to interim financial information and should be read in the context of the December 31, 2017 consolidated financial statements and notes thereto for a more complete understanding of the Partnership’s operations, financial position, and accounting policies.  The December 31, 2017 consolidated financial statements have been filed with the SEC in the Partnership’s 2017 Form 10-K.

These unaudited condensed consolidated financial statements of the Partnership have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial information, and, accordingly, do not include all of the information and footnotes required by GAAP for complete consolidated financial statements. In the opinion of management, these unaudited condensed consolidated financial statements include all adjustments (consisting of normal and recurring accruals) considered necessary for a fair presentation of the Partnership’s financial position as of December 31, 2017 and March 31, 2018, and the results of our operations and cash flows for the three months ended March 31, 2017 and 2018. The Partnership has no items of other comprehensive income; therefore, its net income is equal to its comprehensive income.

Certain costs of doing business incurred by Antero Resources on our behalf have been reflected in the accompanying condensed consolidated financial statements. These costs include general and administrative expenses attributed to us by Antero Resources in exchange for:

Transactions between us and Antero Resources have been identified in the condensed consolidated financial statements (see Note 3—Transactions with Affiliates).

As of the date these condensed consolidated financial statements were filed with the SEC, we completed our evaluation of potential subsequent events for disclosure and no items requiring disclosure were identified, except the declaration of a cash distribution to unitholders, as described in Note 7—Partnership Equity and Distributions.

(b) Revenue Recognition

We provide gathering and compression and water handling and treatment services under fee-based contracts primarily based on throughput or at cost plus a margin. Under these arrangements, we receive fees for gathering oil and gas products, compression services, and water handling and treatment services. The revenue we earn from these arrangements is directly related to (1) in the case of natural gas gathering and compression, the volumes of metered natural gas that we gather, compress and deliver to natural gas compression sites or other transmission delivery points, (2) in the case of oil gathering, the volumes of metered oil that we gather and deliver to other transmission delivery points, (3) in the case of fresh water services, the quantities of fresh water delivered to our customers for use in their well completion operations, (4) in the case of wastewater treatment services, the quantities of wastewater treated for our customers, or (5) in the case of flowback and produced water, the third party out-of-pocket costs we incur plus 3%. We recognize revenue when we satisfy a performance obligation by delivering a service to a customer.

(c) Use of Estimates

The preparation of the condensed consolidated financial statements and notes in conformity with GAAP requires that management formulate estimates and assumptions that affect revenues, expenses, assets, liabilities and the disclosure of contingent assets and liabilities. Items subject to estimates and assumptions include the useful lives of property and equipment and valuation of accrued liabilities, among others. Although management believes these estimates are reasonable, actual results could differ from these estimates.

(d) Cash and Cash Equivalents

We consider all liquid investments purchased with an initial maturity of three months or less to be cash equivalents. The carrying value of cash and cash equivalents approximates fair value due to the short-term nature of these instruments.

(e) Property and Equipment

Property and equipment primarily consists of gathering pipelines, compressor stations, fresh water delivery pipelines and facilities, and our wastewater treatment facility and related landfill to be used for the disposal of waste therefrom, stated at historical cost less accumulated depreciation and amortization. We capitalize construction-related direct labor and material costs. We also capitalize interest on capital costs during the construction phase of the water treatment facility, which is currently undergoing testing and commissioning. We capitalized interest of $3 million for each of the three months ended March 31, 2017 and 2018. Net operating expenses incurred during commissioning are capitalized. Maintenance and repair costs are expensed as incurred.

Depreciation of property and equipment is computed using the straight-line method over the estimated useful lives and salvage values of assets. The depreciation of fixed assets recorded under capital lease agreements is included in depreciation expense. Uncertainties that may impact these estimates of useful lives include, among others, changes in laws and regulations relating to environmental matters, including air and water quality, restoration and abandonment requirements, economic conditions, and supply and demand for our services in the areas in which we operate. When assets are placed into service, management makes estimates with respect to useful lives and salvage values that management believes are reasonable. However, subsequent events could cause a change in estimates, thereby impacting future depreciation amounts.

Amortization of landfill airspace consists of the amortization of landfill capital costs, including those that have been incurred and capitalized and estimated future costs for landfill development and construction, as well as the amortization of asset retirement costs arising from landfill final capping, closure, and post-closure obligations. Amortization expense is recorded on a units-of-consumption basis, applying cost as a rate per-cubic yard. The rate per-cubic yard is calculated by dividing each component of the amortizable basis of the landfill by the number of cubic yards needed to fill the corresponding asset’s airspace. Landfill capital costs and closure and post-closure asset retirement costs are generally incurred to support the operation of the landfill over its entire operating life and are, therefore, amortized on a per-cubic yard basis using a landfill’s total airspace capacity. Estimates of disposal capacity and future development costs are created using input from independent engineers and internal technical teams and are reviewed at least annually. However, subsequent events could cause a change in estimates, thereby impacting future amortization amounts.

Our investment in property and equipment as of the dates presented was as follows (in thousands):

(1) Amortization of landfill costs is recorded over the life of the landfill on a units-of-consumption basis.

(2) Construction-in-progress includes $319 million for the construction of the wastewater treatment facility, which is currently undergoing testing and commissioning.

(f) Asset Retirement Obligations

In December 2017, we completed the construction of a landfill site to be used for the disposal of waste from our wastewater treatment facility. The landfill began accepting waste in January 2018. Our asset retirement obligations relate to our obligation to close, maintain, and monitor landfill cells and support facilities. After an entire landfill has reached capacity and is certified closed, we must continue to maintain and monitor the landfill for a post-closure period, which generally extends 30 years. We record the fair value of our landfill retirement obligations as a liability in the period in which the regulatory obligation to retire a specific asset is triggered. For our individual landfill cells, the required closure and post-closure obligations under the terms of our permits and our intended operation of the landfill cell are triggered and recorded when the cell is placed into service and waste is initially disposed in the landfill cell. The fair value is based on the total estimated costs to close the landfill cell and perform post-closure activities once the landfill cell has reached capacity and is no longer accepting waste. Retirement obligations are increased each year to reflect the passage of time by accreting the balance at the weighted average credit-adjusted risk-free rate that is used to calculate the recorded liability, with accretion charged to direct costs. Actual cash expenditures to perform closure and post-closure activities reduce the retirement obligation liabilities as incurred. After initial measurement, asset retirement obligations are adjusted at the end of each period to reflect changes, if any, in the estimated future cash flows underlying the obligation. Landfill retirement assets are capitalized as the related retirement obligations are incurred, and are amortized on a units-of-consumption basis as the disposal capacity is consumed.

We are under no legal obligations, neither contractually nor under the doctrine of promissory estoppel, to restore or dismantle our gathering pipelines, compressor stations, water delivery pipelines and facilities and water treatment facility upon abandonment. Our gathering pipelines, compressor stations, fresh water delivery pipelines and facilities and water treatment facility have an indeterminate life, if properly maintained. Accordingly, we are not able to make a reasonable estimate of when future dismantlement and removal dates of our pipelines, compressor stations and facilities will occur. It has been determined by our operational management team that abandoning all other ancillary equipment, outside of the assets stated above, would require minimal costs

(g) Equity‑Based Compensation

Our condensed consolidated financial statements reflect various equity-based compensation awards granted by Antero Resources, as well as compensation expense associated with our own plan. These awards include profits interests awards, restricted stock, stock options, restricted units, and phantom units. In each period, we recognize expense in an amount allocated

from Antero Resources, with the offset included in partners’ capital. See Note 3—Transactions with Affiliates for additional information regarding Antero Resources’ allocation of expenses to us.

Under the Antero Midstream Partners LP Long-Term Incentive Plan (“Midstream LTIP”), certain non-employee directors of our general partner and certain officers, employees and consultants of our general partner and its affiliates are eligible to receive awards representing equity interests in the Partnership. An aggregate of 10,000,000 common units may be delivered pursuant to awards under the Midstream LTIP, subject to customary adjustments. For accounting purposes, these units are treated as if they are distributed from us to Antero Resources. Antero Resources recognizes compensation expense for the units awarded to its employees and a portion of that expense is allocated to us. See Note 8—Equity-Based Compensation.

(h) Income Taxes

Our condensed consolidated financial statements do not include a provision for income taxes as we are treated as a partnership for federal and state income tax purposes, with each partner being separately taxed on its distributive share of our items of income, gain, loss, or deduction.

(i) Fair Value Measures

The Financial Accounting Standards Board (the “FASB”) Accounting Standards Codification Topic 820, Fair Value Measurements and Disclosures , clarifies the definition of fair value, establishes a framework for measuring fair value, and expands disclosures about fair value measurements. This guidance also relates to all nonfinancial assets and liabilities that are not recognized or disclosed on a recurring basis (e.g., the initial recognition of asset retirement obligations and impairments of long‑lived assets). The fair value is the price that we estimate would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. A fair value hierarchy is used to prioritize inputs to valuation techniques used to estimate fair value. An asset or liability subject to the fair value requirements is categorized within the hierarchy based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the asset or liability. The highest priority (Level 1) is given to unadjusted quoted market prices in active markets for identical assets or liabilities, and the lowest priority (Level 3) is given to unobservable inputs. Level 2 inputs are data, other than quoted prices included within Level 1, that are observable for the asset or liability, either directly or indirectly.

The carrying values on our balance sheet of our cash and cash equivalents, accounts receivable—Antero Resources, accounts receivable—third party, prepaid expenses, other assets, accounts payable, accounts payable—Antero Resources, accrued liabilities, other current liabilities, other liabilities and the revolving credit facility approximate fair values due to their short-term maturities.

(j) Investments in Unconsolidated Affiliates

The Partnership uses the equity method to account for its investments in companies if the investment provides the Partnership with the ability to exercise significant influence over, but not control, the operating and financial policies of the investee. The Partnership’s consolidated net income includes the Partnership’s proportionate share of the net income or loss of such companies. The Partnership’s judgment regarding the level of influence over each equity method investee includes considering key factors such as the Partnership’s ownership interest, representation on the board of directors and participation in policy-making decisions of the investee and material intercompany transactions. See Note 13–Equity Method Investments.

(k) Adoption of New Accounting Principle

On May 28, 2014, the FASB issued Accounting Standards Update (“ASU”) No. 2014-09, Revenue from Contracts with Customers, which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The ASU replaces most existing revenue recognition guidance in GAAP when it became effective and was incorporated into GAAP as Accounting Standards Codification (“ASC”) Topic 606.  The new standard became effective for us on January 1, 2018. The standard permits the use of either the retrospective or cumulative effect transition

method. We have elected the cumulative effect method. The adoption of ASU 2014-09 did not have a material impact on our financial results. For additional information, see Note 4—Revenue.

(l) Recently Issued Accounting Standard

On February 25, 2016, the FASB issued ASU No. 2016-02, Leases , which requires all leasing arrangements to be presented in the balance sheet as liabilities along with a corresponding asset. The ASU will replace most existing leases guidance in GAAP when it becomes effective.  The new standard becomes effective for us on January 1, 2019.  Although early application is permitted, we do not plan to early adopt the ASU.  The standard requires the use of the modified retrospective transition method.  We are evaluating the effect that ASU 2016-02 will have on our consolidated financial statements and related disclosures. We are evaluating the standard’s applicability to our various contractual arrangements with Antero Resources and have tentatively concluded that the application of the ASU to our contractual arrangements with Antero Resources could be subject to differing interpretations. The accounting treatment for these arrangements under the ASU could include (i) the recognition of our Antero contracts as leases under the ASU, (ii) characterization of our servicing revenues from gathering, compression, and water handling and treatment as revenues from leasing or financing, and (iii) derecognition of assets on our balance sheet that are used to provide services under contracts containing variable payment terms. Other interpretations and applications of the standard are also possible. We continue to monitor relevant industry guidance regarding implementation of ASU 2016-02 and will adjust our implementation of the standard as necessary.  We believe that adoption of the standard will not impact our operational strategies, growth prospects, or cash flow.

(3) Transactions with Affiliates

(a) Revenues

All revenues earned in the three months ended March 31, 2017 and 2018, except revenues earned from third parties, were earned from Antero Resources, under various agreements for gathering and compression and water handling and treatment services.

(b) Accounts receivable—Antero Resources and Accounts payable—Antero Resources

Accounts receivable—Antero Resources represents amounts due from Antero Resources, primarily related to gathering and compression services and water handling and treatment services. Accounts payable—Antero Resources represents amounts due to Antero Resources for general and administrative and other costs.

(c) Allocation of Costs

The employees supporting our operations are employees of Antero Resources. Direct operating expense includes allocated costs of $1.2 million and $1.7 million during the three months ended March 31, 2017 and 2018, respectively, related to labor charges for Antero Resources employees associated with the operation of our gathering lines, compressor stations, and water handling and treatment assets. General and administrative expense includes allocated costs of $13.0 million and $13.2 million during the three months ended March 31, 2017 and 2018, respectively. These costs relate to: (i) various business services, including payroll processing, accounts payable processing and facilities management, (ii) various corporate services, including legal, accounting, treasury, information technology and human resources and (iii) compensation, including equity-based compensation (see Note 8—Equity-Based Compensation for more information). These expenses are charged or allocated to us based on the nature of the expenses and are allocated based on a combination of our proportionate share of gross property and equipment, capital expenditures and labor costs, as applicable. We reimburse Antero Resources directly for all general and administrative costs allocated to us, with the exception of noncash equity compensation allocated to the Partnership for awards issued under the Antero Resources long-term incentive plan or the Midstream LTIP.  

(4) Revenue

(a)   Revenue from Contracts with Customers

All of our revenues are derived from service contracts with customers, and are recognized when we satisfy a performance obligation by delivering a service to a customer. Antero Resources is our most significant customer, and we expect to derive substantially all of our revenues from Antero Resources for the foreseeable future. The following sets forth the nature, timing of satisfaction of performance obligations, and significant payment terms of our contracts with Antero Resources.

Gathering and Compression Agreement

Antero Resources has dedicated all of its current and future acreage in West Virginia, Ohio and Pennsylvania to us for gathering and compression services except for acreage attributable to existing third-party commitments. We also have an option to gather and compress natural gas produced by Antero Resources on any acreage it acquires in the future outside of West Virginia, Ohio and Pennsylvania on the same terms and conditions. Under the gathering and compression agreement, we receive a low pressure gathering fee of $0.30 per Mcf, a high pressure gathering fee of $0.18 per Mcf, and a compression fee of $0.18 per Mcf, in each case subject to CPI-based adjustments since 2014. In addition, the agreement stipulates that we receive a reimbursement for the actual cost of electricity used at our compressor stations.

We satisfy our performance obligations and recognize revenue when low pressure volumes are delivered to a compressor station, high pressure volumes are delivered to a processing plant or transmission pipeline, and compression volumes are delivered to a high pressure line. We invoice the customer the month after each service is performed, and payment is due in the same month.

Water Handling and Treatment Agreement

In connection with Antero Resources’ contribution of Antero Water and certain wastewater treatment assets to us in September 2015 (the “Water Acquisition”), we entered into a water services agreement with Antero Resources whereby we agreed to provide certain water handling and treatment services to Antero Resources within an area of dedication in defined service areas in Ohio and West Virginia. Antero Resources agreed to pay us for all water handling and treatment services provided by us in accordance with the terms of the water services agreement. The initial term of the water services agreement is 20 years from September 23, 2015 and from year to year thereafter until terminated by either party. Under the agreement, we receive a fixed fee of $3.685 per barrel in West Virginia and $3.635 per barrel in Ohio and all other locations for fresh water deliveries by pipeline directly to the well site, as well as $3.116 per barrel for fresh water delivered by truck to high-rate transfer facilities. All of these fees have been subject to annual CPI adjustments since the inception of the agreement in 2015. Antero Resources also agreed to pay us a fixed fee of $4.00 per barrel for wastewater treatment at the advanced wastewater treatment complex, in each case subject to annual CPI-based adjustments and additional fees based on certain costs.

Under the water services agreement, we may also contract with third parties to provide Antero Resources flow back and produced water services. Antero Resources reimburses us for third party out-of-pocket costs plus a 3% markup.

We satisfy our performance obligations and recognize revenue when the fresh water volumes have been delivered to the hydration unit of a specified well pad and the wastewater volumes have been delivered to our wastewater treatment facility. For services contracted through third party providers, our performance obligation is satisfied when the service to be performed by the third party provider has been completed. We invoice the customer the month after each service is performed, and payment is due in the same month.

Minimum Volume Commitments

Both the gathering and compression and water handling and treatment agreements include certain minimum volume commitment provisions, which are intended to support the stability of our cash flows. If and to the extent Antero Resources requests that we construct new high pressure lines and compressor stations, the gathering and compression agreement contains minimum volume commitments that require Antero Resources to utilize or pay for 75% and 70%, respectively, of the capacity of such new construction for 10 years. Antero Resources also committed to pay a fee on a minimum volume of fresh water deliveries in calendar years 2016 through 2019. Antero Resources is obligated to pay a minimum volume fee to us in the event the aggregate volume of fresh water delivered to Antero Resources under the water services agreement is less than 120,000 barrels per day in 2018 and 2019. We recognize revenue related to these minimum volume commitments at the time it is determined that the volumes will not be consumed by Antero Resources, and the amount of the shortfall is known.

Minimum revenue amounts under the minimum volume commitments are as follows (in thousands):

(b)   Disaggregation of Revenue

In the following table, revenue is disaggregated by type of service and type of fee (in thousands). The table also identifies the reportable segment to which the disaggregated revenues relate. For more information on reportable segments, see Note 14—Reportable Segments.

(c)   Transaction Price Allocated to Remaining Performance Obligations

The majority of our service contracts have a term greater than one year, and as such we have utilized the practical expedient in ASC 606, which states that a company is not required to disclose the transaction price allocated to remaining performance obligations if the variable consideration is allocated entirely to a wholly unsatisfied performance obligation. Under our service contracts, each unit of product delivered to the customer represents a separate performance obligation; therefore, future volumes are wholly unsatisfied and thus disclosure of the transaction price allocated to remaining performance obligations is not required.

The remainder of our service contracts, which relate to contracts with third parties, are short-term in nature with a contract term of one year or less. We have utilized an additional practical expedient in ASC 606 which exempts us from disclosure of the transaction price allocated to remaining performance obligations if the performance obligation is part of a contract that has an original expected duration of one year or less.

(d)   Contract Balances

Under our service contracts, we invoice customers after our performance obligations have been satisfied, at which point payment is unconditional. Accordingly, our service contracts do not give rise to contract assets or liabilities under ASC 606. At December 31, 2017 and March 31, 2018, our receivables from contracts with customers were $110 million and $111 million, respectively.

(5) Long-Term Debt

Long-term debt was as follows at December 31, 2017 and March 31, 2018 (in thousands):

(a) Revolving Credit Facility

On October 26, 2017, we entered into an amended and restated senior revolving credit facility (our “Credit Facility” or “revolving credit facility”). The Credit Facility provides for fall away covenants and lower interest rates that are triggered if and when elect to enter into an Investment Grade Period, as described below.

Lender commitments under the Credit Facility are $1.5 billion and the maturity date of the Credit Facility is October 26, 2022. Under the Credit Facility, “Investment Grade Period” is a period that, as long as no event of default has occurred and the Partnership is in pro forma compliance with the financial covenants under the Credit Facility, commences when the Partnership elects to give notice to the Administrative Agent that the Partnership has received at least one of either (i) a BBB- or better rating from Standard and Poor’s or (ii) a Baa3 or better from Moody’s (provided that the non-investment grade rating from the other rating agency is at least either Ba1 if Moody’s or BB+ if Standard and Poor’s (an “Investment Grade Rating”)). An Investment Grade Period can end at the Partnership’s election.    

During a period that is not an Investment Grade Period, the Credit Facility is ratably secured by mortgages on substantially all of our properties, including the properties of our subsidiaries, and guarantees from our subsidiaries. During an Investment Grade Period, the liens securing the obligations thereunder shall be automatically released (subject to the provisions of the Credit Facility).

The revolving credit facility contains certain covenants including restrictions on indebtedness, and requirements with respect to leverage and interest coverage ratios; provided, however, that during an Investment Grade Period, such covenants become less restrictive on the Partnership. The revolving credit facility permits distributions to the holders of our equity interests in accordance with the cash distribution policy adopted by the board of directors of our general partner in connection

with the Partnership’s initial public offering, provided that no event of default exists or would be caused thereby, and only to the extent permitted by our organizational documents. The Partnership was in compliance with all of the financial covenants under the Credit Facility as of December 31, 2017 and March 31, 2018.

Principal amounts borrowed are payable on the maturity date with such borrowings bearing interest that is payable quarterly or, in the case of Eurodollar Rate Loans, at the end of the applicable interest period if shorter than six months. Interest is payable at a variable rate based on LIBOR or the base rate, determined by election at the time of borrowing, plus an applicable margin rate.  Interest at the time of borrowing is determined with reference to (i) during any period that is not an Investment Grade Period, the Partnership’s then-current leverage ratio and (ii) during an Investment Grade Period, with reference to the rating given to the Partnership by Moody’s or Standard and Poor’s.  During any period that is not an Investment Grade Period, the applicable margin rates range from 25 basis points to 225 basis points. During an Investment Grade Period, the applicable margin rates range from 12.5 basis points to 200 basis points.  Commitment fees on the unused portion of the revolving credit facility are due quarterly at rates ranging from 0.25% to 0.375% based on the leverage ratio, during a period that is not an Investment Grade Period, and 0.175% to 0.375% based on the Partnership’s rating during an Investment Grade Period.

At December 31, 2017 and March 31, 2018, we had borrowings under the Credit Facility of $555 million and $660 million, respectively, with a weighted average interest rate of 2.81% and 2.95%, respectively.  No letters of credit were outstanding at December 31, 2017 or March 31, 2018 under the Credit Facility. 

(b) 5.375% Senior Notes Due 2024

On September 13, 2016, the Partnership and its wholly-owned subsidiary, Finance Corp, as co-issuers, issued $650 million in aggregate principal amount of 5.375% senior notes due September 15, 2024 (the “2024 Notes”) at par.  The 2024 Notes are unsecured and effectively subordinated to the revolving credit facility to the extent of the value of the collateral securing the revolving credit facility.  The 2024 Notes are fully and unconditionally guaranteed on a joint and several senior unsecured basis by the Partnership’s wholly-owned subsidiaries (other than Finance Corp) and certain of its future restricted subsidiaries.  Interest on the 2024 Notes is payable on March 15 and September 15 of each year.  The Partnership may redeem all or part of the 2024 Notes at any time on or after September 15, 2019 at redemption prices ranging from 104.031% on or after September 15, 2019 to 100.00% on or after September 15, 2022.  In addition, prior to September 15, 2019, the Partnership may redeem up to 35% of the aggregate principal amount of the 2024 Notes with an amount of cash not greater than the net cash proceeds of certain equity offerings, if certain conditions are met, at a redemption price of 105.375% of the principal amount of the 2024 Notes, plus accrued and unpaid interest.  At any time prior to September 15, 2019, the Partnership may also redeem the 2024 Notes, in whole or in part, at a price equal to 100% of the principal amount of the 2024 Notes plus a “make-whole” premium and accrued and unpaid interest.  If the Partnership undergoes a change of control, the holders of the 2024 Notes will have the right to require the Partnership to repurchase all or a portion of the notes at a price equal to 101% of the principal amount of the 2024 Notes, plus accrued and unpaid interest.

(6)  Accrued Liabilities

Accrued liabilities as of December 31, 2017 and March 31, 2018 consisted of the following items (in thousands):

(7) Asset Retirement Obligations

The following is a reconciliation of our asset retirement obligations for the period shown below (in thousands):

(8) Equity-Based Compensation

Our general and administrative expenses include equity-based compensation costs allocated to us by Antero Resources for grants made pursuant to Antero Resources’ long‑term incentive plan and the Midstream LTIP. Equity‑based compensation expense allocated to us was $6.3 million and $6.2 million for the three months ended March 31, 2017 and 2018, respectively. These expenses were allocated to us based on our proportionate share of Antero Resources’ labor costs. Antero Resources has unamortized expense totaling approximately $88.1 million as of March 31, 2018 related to its various equity-based compensation plans, which includes the Midstream LTIP. A portion of this will be allocated to us as it is amortized over the remaining service period of the related awards. The Partnership does not reimburse Antero Resources for noncash equity compensation allocated to it for awards issued under the Antero Resources long-term incentive plan or the Midstream LTIP.

Midstream LTIP

Our general partner manages our operations and activities, and Antero Resources employs the personnel who provide support to our operations. Our general partner has adopted the Midstream LTIP, pursuant to which non‑employee directors of our general partner and certain officers, employees and consultants of our general partner and its affiliates are eligible to receive awards representing limited partner interests in the Partnership. An aggregate of 10,000,000 common units may be delivered pursuant to awards under the Midstream LTIP, subject to customary adjustments. A total of 7,876,693 common units are available for future grant under the Midstream LTIP as of March 31, 2018. Restricted units and phantom units granted under the Midstream LTIP vest subject to the satisfaction of service requirements, upon the completion of which common units in the Partnership are delivered to the holder of the restricted units or phantom units. Phantom units also contain distribution equivalent rights which entitle the holder of vested common units to receive a “catch up” payment equal to common unit distributions paid during the vesting period of the phantom unit award. Compensation related to each restricted unit and phantom unit award is recognized on a straight-line basis over the requisite service period of the entire award. The grant date fair values of these awards are determined based on the closing price of the Partnership’s common units on the date of grant. These units are accounted for as if they are distributed by the Partnership to Antero Resources. Antero Resources recognizes compensation expense for the units awarded and a portion of that expense is allocated to the Partnership. Antero Resources allocates equity-based compensation expense to the Partnership based on our proportionate share of Antero Resources’ labor costs. The Partnership’s portion of the equity-based compensation expense is included in general and administrative expenses, and recorded as a credit to the applicable classes of partners’ capital.

A summary of restricted unit and phantom unit awards activity during the three months ended March 31, 2018 is as follows:

Intrinsic values are based on the closing price of the Partnership’s common units on the referenced dates. Midstream LTIP unamortized expense of $20.4 million at March 31, 2018, is expected to be recognized over a weighted average period of approximately 1.9 years and our proportionate share will be allocated to us as it is recognized.

(9) Partnership Equity and Distributions

Our Minimum Quarterly Distribution

Our partnership agreement provides for a minimum quarterly distribution of $0.17 per unit for each quarter, or $0.68 per unit on an annualized basis.

If cash distributions to our unitholders exceed $0.1955 per common unit in any quarter, our unitholders and the holder of our incentive distribution rights (“IDRs”), will receive distributions according to the following percentage allocations:

General Partner Interest

Our general partner owns a non-economic general partner interest in us, which does not entitle it to receive cash distributions. However, our general partner is under common control with the holder of the IDRs and may in the future own common units or other equity interests in us and will be entitled to receive distributions on any such interests.

Cash Distributions

The board of directors of our general partner has declared a cash distribution of $0.39 per unit for the quarter ended March 31, 2018. The distribution will be payable on May 18, 2018 to unitholders of record as of May 3, 2018.

The following table details the amount of quarterly distributions the Partnership paid for each of its partnership interests, with respect to the quarter indicated (in thousands, except per unit data):

* Distribution equivalent rights on limited partner interests that vested under the Midstream LTIP.

(10) Net Income Per Limited Partner Unit

The Partnership’s net income is attributed to the general partner and limited partners, in accordance with their respective ownership percentages, and when applicable, giving effect to incentive distributions paid to the holder of the incentive distribution rights. Basic and diluted net income per limited partner unit is calculated by dividing limited partners’ interest in net income, less incentive distributions, by the weighted average number of outstanding limited partner units during the period.

We compute earnings per unit using the two-class method for master limited partnerships. Under the two-class method, earnings per unit is calculated as if all of the earnings for the period were distributed under the terms of the partnership agreement, regardless of whether the general partner has discretion over the amount of distributions to be made in any particular period, whether those earnings would actually be distributed during a particular period from an economic or practical perspective, or whether the general partner has other legal or contractual limitations on its ability to pay distributions that would prevent it from distributing all of the earnings for a particular period.

We calculate net income available to limited partners based on the distributions pertaining to the current period’s net income. After adjusting for the appropriate period’s distributions, the remaining undistributed earnings or excess distributions over earnings, if any, are attributed in accordance with the contractual terms of the partnership agreement under the two-class method.

Basic earnings per unit is computed by dividing net earnings attributable to unitholders by the weighted average number of units outstanding during each period. Diluted net income per limited partner unit reflects the potential dilution that could occur if agreements to issue common units, such as awards under long-term incentive plans, were exercised, settled or converted into common units. When it is determined that potential common units resulting from an award should be included in the diluted net income per limited partner unit calculation, the impact is reflected by applying the treasury stock method. Earnings per common unit assuming dilution for the three months ended March 31, 2018 was calculated based on the diluted weighted average number of units outstanding of 187,172,540, including 238,799 dilutive units attributable to non-vested restricted unit and phantom unit awards. For the three months ended March 31, 2018 there were no non-vested phantom unit and restricted unit awards that were anti-dilutive and therefore excluded from the calculation of diluted earnings per unit.

The Partnership’s calculation of net income per limited partner unit for the periods indicated is as follows (in thousands, except per unit data):

(11) Sale of Common Units Under Equity Distribution Agreement

During the third quarter of 2016, the Partnership entered into an Equity Distribution Agreement (the “Distribution Agreement”), pursuant to which the Partnership may sell, from time to time through brokers acting as its sales agents, common units representing limited partner interests having an aggregate offering price of up to $250 million.  The program is registered with the SEC on an effective registration statement on Form S-3. Sales of the common units may be made by means of ordinary brokers’ transactions on the New York Stock Exchange, at market prices, in block transactions, or as otherwise agreed to between the Partnership and the sales agents.  Proceeds are expected to be used for general partnership purposes, which may include repayment of indebtedness and funding working capital or capital expenditures.  The Partnership is under no obligation to offer and sell common units under the Distribution Agreement.

The Partnership did not issue or sell any common units under the Distribution Agreement during the three months ended March 31, 2018. As of March 31, 2018, additional common units under the Distribution Agreement up to an aggregate sales price of $157.3 million were available for issuance.

(12) Fair Value Measurement

In connection with the Water Acquisition, we have agreed to pay Antero Resources (a) $125 million in cash if the Partnership delivers 176,295,000 barrels or more of fresh water during the period between January 1, 2017 and December 31, 2019 and (b) an additional $125 million in cash if the Partnership delivers 219,200,000 barrels or more of fresh water during the period between January 1, 2018 and December 31, 2020. This contingent consideration liability is valued based on Level 3 inputs related to expected average volumes and weighted average cost of capital.

The following table provides a reconciliation of changes in Level 3 financial liabilities measured at fair value on a recurring basis for the period shown below (in thousands):

We account for contingent consideration in accordance with applicable accounting guidance pertaining to business combinations. We are contractually obligated to pay Antero Resources contingent consideration in connection with the Water Acquisition, and therefore recorded this contingent consideration liability at the time of the Water Acquisition. We update our assumptions each reporting period based on new developments and adjust such amounts to fair value based on revised

assumptions, if applicable, until such consideration is satisfied through payment upon achievement of the specified objectives or it is eliminated upon failure to achieve the specified objectives.

As of March 31, 2018, we expect to pay the entire amount of the contingent consideration amounts in 2019 and 2020. The fair value measurement is based on significant inputs not observable in the market and thus represents a Level 3 measurement within the fair value hierarchy. The fair value of the contingent consideration liability associated with future milestone payments was based on the risk adjusted present value of the contingent consideration payout.

The carrying values of accounts receivable and accounts payable at December 31, 2017 and March 31, 2018 approximated fair value because of their short-term nature. The carrying value of the amounts under the revolving credit facility at December 31, 2017 and March 31, 2018 approximated fair value because the variable interest rates are reflective of current market conditions.

Based on Level 2 market data inputs, the fair value of the Partnership’s 2024 Notes was approximately $651.6 million at March 31, 2018.

(13) Equity Method Investments

In the second quarter of 2016, we exercised our option to purchase a 15% equity interest in Stonewall, which operates the 67-mile Stonewall pipeline on which Antero Resources is an anchor shipper.

On February 6, 2017, we formed the Joint Venture to develop processing and fractionation assets in Appalachia with MarkWest, a wholly owned subsidiary of MPLX, LP. We and MarkWest each own a 50% equity interest in the Joint Venture and MarkWest operates the Joint Venture assets. The Joint Venture assets consist of processing plants in West Virginia, and a one-third interest in a MarkWest fractionator in Ohio.

Our net income includes our proportionate share of the net income of the Joint Venture and Stonewall. When we record our proportionate share of net income, it increases equity income in the condensed consolidated statements of operations and comprehensive income and the carrying value of that investment on its balance sheet. When distributions on our proportionate share of net income are received, they are recorded as reductions to the carrying value of the investment on the balance sheet and are classified as cash inflows from operating activities in accordance with the nature of the distribution approach under ASU No. 2016-15. We use the equity method of accounting to account for our investments in Stonewall and the Joint Venture because we exercise significant influence, but not control, over the entities. Our judgment regarding the level of influence over our equity investments includes considering key factors such as our ownership interest, representation on the board of directors and participation in policy-making decisions of Stonewall and the Joint Venture.

The following table is a reconciliation of our investments in these unconsolidated affiliates (in thousands):

(14)     Reporting Segments

The Partnership’s operations are located in the United States and are organized into two reporting segments: (1) gathering and processing and (2) water handling and treatment.

Gathering and Processing

The gathering and processing segment includes a network of gathering pipelines and compressor stations, that collect and process production from Antero Resources’ wells in West Virginia and Ohio. The gathering and processing segment also includes equity in earnings from processing and fractionation plants through our equity in the Joint Venture with MarkWest.

Water Handling and Treatment

The Partnership’s water handling and treatment segment includes two independent systems that deliver fresh water from sources including the Ohio River, local reservoirs as well as several regional waterways. The water handling and treatment segment also includes a wastewater treatment facility that is currently undergoing testing and commissioning, as well as other fluid handling services which includes high rate transfer, wastewater transportation, disposal and treatment. See Note 2—Summary of Significant Accounting Polices, Property and Equipment.

These segments are monitored separately by management for performance and are consistent with internal financial reporting. These segments have been identified based on the differing products and services, regulatory environment and the expertise required for these operations. We evaluate the performance of the Partnership’s business segments based on operating income. Interest expense is primarily managed and evaluated on a consolidated basis.

Summarized financial information concerning the Partnership’s segments for the periods indicated is shown in the following table (in thousands):