Exhibit 4.27

INDENTURE OF TRUST

between

CLARK COUNTY, NEVADA

and

THE BANK OF NEW YORK MELLON TRUST COMPANY N.A.,

as Trustee

relating to

CLARK COUNTY, NEVADA

INDUSTRIAL DEVELOPMENT REVENUE BONDS

(SOUTHWEST GAS CORPORATION PROJECT)

SERIES 2009A

Dated as of December 1, 2009

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THIS INDENTURE OF TRUST, made and entered into as of December 1, 2009 (this “Indenture”), by and between CLARK COUNTY, NEVADA, a political subdivision of the State of Nevada (the “Issuer”), and THE BANK OF NEW YORK MELLON TRUST COMPANY N.A., a national banking association organized, existing and authorized to accept and execute trusts of the character herein set out under the laws of the United States of America, acting not in its individual capacity, but solely as Trustee (the “Trustee”).

W I T N E S S E T H :

WHEREAS, the Issuer is a public instrumentality and political subdivision of the State of Nevada organized and existing under the County Economic Development Revenue Bond Law Sections 244A.669 to 244A.763, inclusive, of the Nevada Revised Statutes, as supplemented and amended (the “Act”), and is authorized by the Act to issue its revenue bonds for the purpose of paying all or any part of the costs of a “project” as defined in the Act; and

WHEREAS, Southwest Gas Corporation, a California corporation (the “Borrower”), has duly caused an application to be filed with the Issuer and has requested that the Issuer issue bonds to finance a portion of the cost of the acquisition, construction and installation of a “project” within the meaning of the Act, consisting of the upgrade, improvement, addition and replacement of facilities for local furnishing of natural gas located in Clark County, Nevada, as more particularly described in Appendix A to the Agreement, as hereinafter defined (the “Project”); and

WHEREAS, the Issuer, after due investigation and deliberation, has adopted a resolution approving said request and authorizing the issuance of bonds to finance a portion of the cost of the acquisition, construction, and installation of the Project, and for that purpose has determined to issue its Industrial Development Revenue Bonds (Southwest Gas Corporation Project) Series 2009A (the “Bonds”); and

WHEREAS, concurrently with the execution and delivery of this Indenture, the Issuer is entering into a Financing Agreement, dated the date hereof (the “Agreement”), with the Borrower specifying the terms and conditions of the financing of a portion of the cost of the acquisition and construction of the Project by the Borrower, the lending of the proceeds of the Bonds to the Borrower for such purpose, and the repayment by the Borrower of such loan; and

WHEREAS, to provide for the authentication and delivery of the Bonds, to establish and declare the terms and conditions upon which the Bonds are to be issued and secured and to secure the payment of the principal thereof and of the interest and premium, if any, thereon, the Issuer has authorized the execution and delivery of this Indenture; and

WHEREAS, the Bonds are to be issued in a total aggregate principal amount not to exceed $50,000,000 and are to be sold and delivered to provide proceeds, as a loan to the Borrower, to finance a portion of the cost of the acquisition, construction, and installation of the Project; and

WHEREAS, the Bonds and the Trustee’s certificate of authentication and the form of assignment to be endorsed thereon shall be in substantially the forms set forth in

Appendix A to this Indenture, with necessary and appropriate variations, omissions and insertions as permitted or required by this Indenture;

WHEREAS, all acts and proceedings required by law necessary to make the Bonds when executed by the Issuer, authenticated and delivered by the Trustee and duly issued, the valid, binding and legal limited obligations of the Issuer, and to constitute this Indenture a valid and binding agreement for the uses and purposes herein set forth, in accordance with its terms, have been done and taken; and the execution and delivery of this Indenture have been in all respects duly authorized;

NOW, THEREFORE, THIS INDENTURE OF TRUST WITNESSETH:

That the Issuer in consideration of the premises, the acceptance by the Trustee of the trust hereby created, the purchase and acceptance of the Bonds by the purchasers thereof, one dollar duly paid to the Issuer by the Trustee at or before the execution and delivery of these presents and of other good and valuable considerations, the receipt of which is hereby acknowledged, and in order to secure the payment of the principal of and premium, if any, and interest on all Bonds outstanding hereunder from time to time, according to their tenor and effect, and to secure the observance and performance by the Issuer of all the covenants expressed or implied herein and in the Bonds, does hereby pledge and assign unto the Trustee and unto its successors and assigns forever;

GRANTING CLAUSE FIRST

The Agreement, including all extensions and renewals of the term thereof, if any, together with all right, title and interest of the Issuer therein (except for Reserved Rights) including, but without limiting the generality of the foregoing, the present and continuing right to receive, collect or make claim for any of the moneys, income, revenues, issues, profits and other amounts payable or receivable thereunder, including payments made by the Borrower under the Agreement (excepting only payments made by the Borrower pursuant to the Tax Certificate (as defined herein) in order to make rebate payments to the United States), to bring actions and proceedings thereunder or for the enforcement thereof, and to do any and all things which the Issuer or any other person is or may become entitled to do under the Agreement;

GRANTING CLAUSE SECOND

All Revenues (as defined herein) received by the Issuer under the Agreement and all moneys and earnings thereon held by the Trustee in the Construction Fund, the Costs of Issuance Fund, or in the Bond Fund under the terms of this Indenture; and

GRANTING CLAUSE THIRD

Any and all other property of each name and nature from time to time hereafter by delivery or by writing of any kind pledged or assigned as and for additional security hereunder, by the Issuer or by anyone on its behalf or with its written consent, to the Trustee, which are hereby authorized to receive any and all such property at any and all times and to hold and apply the same subject to the terms hereof.

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TO HAVE AND TO HOLD all and singular the Trust Estate, whether now owned or hereafter acquired, unto the Trustee and its successors in said trusts and assigns forever.

IN TRUST NEVERTHELESS, upon the terms and trusts herein set forth for the equal and proportionate benefit, security and protection of all present and future Bondholders, from time to time issued under and secured by this Indenture without privilege, priority or distinction as to the lien or otherwise of any of the Bonds over any of the other Bonds (except only as otherwise expressly stated herein) and thereafter to secure the Bank to the extent of its interest herein.

PROVIDED HOWEVER, that if the Issuer, its successors or assigns, shall cause to be paid, the principal of the Bonds and the interest and premium, if any, due or to become due thereon, at the times and in the manner mentioned in the Bonds, according to the true intent and meaning thereof, and shall cause the payments to be made into the Bond Fund as required under Article VI hereof or shall provide, as permitted by Article VIII hereof, for the payment thereof, and shall keep, perform and observe all the covenants and conditions pursuant to the terms of this Indenture to be kept, performed and observed by it, and shall pay or cause to be paid to the Trustee and the Bank all sums of money due or to become due, to each of them, respectively, in accordance with the terms and provisions hereof, then this Indenture and the rights hereby granted shall cease, determine and be void except as set forth in such Article VIII.

THIS INDENTURE OF TRUST FURTHER WITNESSETH, and it is expressly declared, that all Bonds issued and secured hereunder are to be issued, authenticated and delivered and the Trust Estate hereby assigned and pledged are to be dealt with and disposed of under, upon and subject to the terms, conditions, stipulations, covenants, agreements, trusts, uses and purposes as hereinafter expressed, and the Issuer has agreed and covenanted, and does hereby agree and covenant, with the Trustee and with the respective Owners from time to time of the Bonds and the Bank, to the extent of its interest herein, as follows:

ARTICLE I

DEFINITIONS AND RULES OF INTERPRETATION

SECTION 1.01 RULES OF INTERPRETATION. For all purposes of this Indenture, except as otherwise expressly provided or unless the context otherwise requires:

(A) All references in this Indenture to designated “Articles”, “Sections” and other subdivisions are to the designated Articles, Sections and other subdivisions of this Indenture.

(B) The words “herein”, “hereof”, “hereto”, “hereby”, and “hereunder” and other words of similar import refer to this Indenture as a whole and not to any particular Article, Section or other subdivision.

(C) The terms defined in this Article have the meanings assigned to them in this Article, and include the plural as well as the singular.

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(D) All accounting terms not otherwise defined herein have the meanings assigned to them in accordance with generally accepted accounting principles as in effect in the United States from time to time.

(E) Every “request”, “order”, “demand”, “application”, “appointment”, “notice”, “statement”, “certificate”, “consent”, “direction”, “instruction” or similar action hereunder by the Issuer shall, unless the form thereof is specifically provided, be in writing signed by the Authorized Issuer Representative.

(F) All references to the “Bank,” the “Liquidity Provider” or the “Bond Insurer” apply only at such time as any Bank, Liquidity Provider or Bond Insurer is then providing a Letter of Credit, Liquidity Facility or Bond Insurance, as applicable.

(G) All references to the “Remarketing Agent,” the “Auction Agent,” the “Tender Agent,” and the “Broker-Dealer” apply only at such time as any Remarketing Agent, Auction Agent, Tender Agent or Broker-Dealer is then acting as a remarketing agent, auction agent, tender agent or broker-dealer, as applicable, with respect to the Bonds.

(H) All other terms used herein which are defined in the Agreement shall have the same meanings assigned them in the Agreement unless the context otherwise requires.

SECTION 1.02 DEFINITIONS. In addition to the terms defined in the recitals hereto, for all purposes of this Indenture and the Agreement, except as otherwise expressly provided or unless the context otherwise requires, the following terms shall have the following meanings; provided , however , that any terms used herein relating to Auction Bonds that are not expressly defined below shall be deemed to have the meanings provided in Appendix C, Auction Procedures, attached hereto:

“Act” means the County Economic Development Revenue Bond Law Sections 244A.669 to 244A.763, inclusive, of the Nevada Revised Statutes, as amended and supplemented.

“Administrative Expenses” means any and all reasonable and necessary expenses (including the reasonable and necessary out-of-pocket expenses and fees of Counsel) incurred by the Issuer in connection with the Bonds, the Agreement, this Indenture and any transaction or event contemplated by the Agreement or this Indenture, and any agency of the State selected by the Issuer to act on its behalf in connection with the Bonds, including any and all reasonable expenses incurred by the Attorney General of the State in connection with any litigation which may at any time be instituted involving the Bonds.

“Agreement” means the Financing Agreement of even date herewith by and between the Issuer and the Borrower, as from time to time amended and supplemented.

“Auction Agent” has the meaning, at any time as applicable, set forth in Appendix C, Auction Procedures, attached hereto.

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“Auction Bond” means, at any time as applicable, any Bond that bears interest at an Auction Rate.

“Auction Rate” has the meaning set forth in Appendix C, Auction Procedures, attached hereto.

“Auction Rate Period” has the meaning set forth in Appendix C, Auction Procedures, attached hereto.

“Authorized Borrower Representative” means the Chief Executive Officer, the President, the Chief Financial Officer, Treasurer or any Assistant Treasurer of the Borrower or any person at the time designated to act on behalf of the Borrower by a written certificate furnished to the Issuer, the Remarketing Agent, and the Trustee containing the specimen signature of such person and signed on behalf of the Borrower by any officer of the Borrower. Such certificate may designate an alternate or alternates.

“Authorized Denominations” means (i) with respect to Bonds during any Term Rate Period, $5,000 and any integral multiple thereof; (ii) with respect to Bonds during any Auction Rate Period, the Authorized Denominations set forth in Appendix C, Auction Procedures, attached hereto and (iii) with respect to Bonds during any other Rate Period, $100,000 and any integral multiple of $5,000 in excess thereof, except that one Bond may be in a denomination of any amount in excess of $100,000.

“Authorized Issuer Representative” means the Chair of the Board of Commissioners of the Issuer or any person at the time designated to act on behalf of the Issuer by a written certificate furnished to the Borrower and the Trustee containing the specimen signature of such person and signed on behalf of the Issuer by the Chair of the Board of Commissioners of the Issuer.

“Available Moneys” means (1) proceeds of the Bonds received from the original issuance and sale of the Bonds; (2) proceeds from the remarketing of any Bonds tendered for purchase pursuant to this Indenture and purchased by any Person other than the Issuer or the Borrower (or any “insider,” as defined in the United States Bankruptcy Code, of the Issuer or the Borrower); (3) moneys derived from drawings under the Letter of Credit that are not commingled with any other moneys; (4) moneys held by the Trustee in funds and accounts established under this Indenture (other than in the Rebate Fund, the Letter of Credit Account or as described in Section 6.07 hereof) and subject to a first priority perfected lien under this Indenture for a period of at least 124 days and not commingled with any moneys so held for less than said period and during and prior to which period no petition in bankruptcy was filed by or against, and no receivership, insolvency, assignment for the benefit of creditors or other similar proceeding has been commenced by or against, the Issuer or the Borrower, unless such petition or proceeding was dismissed and all applicable appeal periods have expired without an appeal having been filed; (5) investment income derived from the investment of moneys described in clause (1), (2), (3), or (4); or (6) moneys as to which there has been delivered to the Trustee an opinion of nationally recognized bankruptcy counsel to the effect that the payment of such moneys to the Bondholders would not constitute transfers avoidable under 11 U.S.C Section

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547(b) and recoverable from the Bondholders under 11 U.S.C. Section 550(a) should the Borrower or the Authority be the debtor in a case under the United States Bankruptcy Code.

“Bank” means, at any time as applicable, any commercial bank, savings association or other financial institution issuing a Letter of Credit to support the Bonds, which will be a party to a Reimbursement Agreement.

“Bank Bonds” shall have the meaning ascribed thereto in Section 4.06(b)(i) hereof.

“Bank Default” means any of the following events: (i) the Bank shall fail, wholly or partially, to make a payment when and as required under the provisions of the Letter of Credit; (ii) the Letter of Credit is surrendered, cancelled or terminated (other than through normal expiration in accordance with its terms), or amended or modified in any material respect, without the Trustee’s prior written consent; (iii) a court of competent jurisdiction enters a final nonappealable judgment that the Letter of Credit is not valid and binding on or enforceable against the Bank; or (iv) the occurrence and continuation of one or more of the following: (A) the liquidation or dissolution of the Bank; (B) the commencement by the Bank of a voluntary case or other proceeding seeking liquidation, reorganization or other relief with respect to itself or its debts under any bankruptcy, insolvency or other similar law now or hereafter in effect, including without limitation the appointment of a trustee, receiver, liquidator, custodian or other similar official for itself or any substantial part of its property; (C) the consent of the Bank to or the acquiescence by the Bank in any case or proceeding described in the preceding clause (B) that is commenced against it; (D) the making by the Bank of an assignment for the benefit of creditors; (E) the failure of the Bank or the admission by the Bank in writing of its inability generally to pay its debts or claims as they become due; (F) the initiation by the Bank of any actions to authorize any of the foregoing; (G) the commencement of an involuntary case or other proceeding against the Bank seeking liquidation, reorganization or other relief with respect to it or its debts under any bankruptcy, insolvency or other similar law now or hereafter in effect or seeking the appointment of a trustee, receiver, liquidator, custodian or other similar official of it or any substantial part of its property, and such involuntary case remaining undismissed and unstayed for a period of 60 days; or (H) the entering of an order for relief against the Bank under the federal bankruptcy law as now or hereafter in effect.

“Bond” or “Bonds” means any one or more of the bonds authorized, authenticated and delivered under this Indenture.

“Bond Counsel” means nationally recognized municipal bond counsel mutually acceptable to the Issuer, the Trustee and the Borrower, but shall not include Counsel to the Borrower. An “opinion of Bond Counsel” means a written opinion of Bond Counsel addressed to the Issuer and delivered to the Issuer, the Trustee and the Borrower.

“Bond Fund” means the fund created by Section 6.02 hereof.

“Bond Insurance” means, at any time as applicable, any bond insurance policy securing the payment of principal of the Bonds on the stated maturity date thereof and the

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payment of interest on the Bonds on each Interest Payment Date therefor, delivered pursuant to and meeting the requirements of Section 5.17 of the Agreement.

“Bond Insurer” means, at any time as applicable, any insurance company, surety or other financial institution providing Bond Insurance then in effect.

“Bondholder” or “holder” or “Owner” or “owner of Bonds” means the Person or Persons in whose name or names a Bond shall be registered on books of the Issuer kept by the Registrar for that purpose in accordance with the terms of this Indenture; provided, however, with respect to Book-Entry Bonds the term “Owner” shall mean the beneficial owners of the Bonds as the context may require.

“Book-Entry Bond” means a Bond authorized to be issued to and, except as provided in subsections (c) or (d) of Section 2.13 of this Indenture, restricted to being registered in the name of a Securities Depository.

“Borrower” means Southwest Gas Corporation, a California corporation qualified to do business in the State, and its successors and assigns and any surviving, resulting or transferee corporation as permitted in Section 5.2 of the Agreement.

“Borrower Bonds” means any Bond registered to the Borrower or any affiliate thereof or held by the Trustee for the account of the Borrower.

“Business Day” means a day on which banking institutions located in New York, New York, or in the city in which the principal corporate trust office of the Trustee is located or the payment office for the Bond Insurer, the Bank or the Liquidity Provider, at which demands for payment of the Bond Insurance, Letter of Credit or Liquidity Facility are to be presented, are not required or authorized to remain closed and on which the New York Stock Exchange is not closed; provided, however, that during an Auction Rate Period, this definition of “Business Day” shall be supplemented as provided in Appendix C, Auction Procedures, attached hereto.

“Code” means the Internal Revenue Code of 1986, as amended, and regulations promulgated or proposed thereunder or (to the extent applicable) under prior law, including temporary regulations.

“Completion Date” means the date of completion of the Project as certified under Section 5.3 of the Agreement.

“Construction Fund” means the fund created by Section 6.07 hereof.

“Cost” or “Cost of the Project” means the sum of the items authorized to be paid from the Construction Fund pursuant to the provisions of paragraphs (a) to (g), inclusive, of Section 3.3 of the Agreement.

“Costs of Issuance” means all items of expense directly or indirectly payable by or reimbursable to the Issuer or the Borrower and related to the authorization, issuance, sale and delivery of the Bonds, including but not limited to costs of preparation and reproduction of documents, printing expenses, filing and recording fees, initial fees and charges of the Trustee,

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legal fees and charges, fees and disbursements of consultants and professionals, Rating Agency fees, fees and charges for preparation, execution and safekeeping of the Bonds and any other cost, charge or fee in connection with the original issuance of the Bonds which constitutes a “cost of issuance” within the meaning of Section 147(g) of the Code.

“Counsel” means an attorney at law or a firm of attorneys (who may be an employee of or counsel to the Issuer or the Borrower) duly admitted to the practice of law before the highest court of any state of the United States of America or of the District of Columbia.

“Daily Rate” means the interest rate on the Bonds established in accordance with Section 2.03(a) hereof.

“Daily Rate Period” means each period during which Bonds bear interest at Daily Rates.

“Dated Date” means the date of issuance and delivery of the Bonds to the Initial Purchasers thereof.

“Default” or “default” means any event which with the giving of notice, the passage of time, or both, becomes an “event of default”.

“DTC” means The Depository Trust Company, a limited purpose trust company organized under the laws of the State of New York, and its successors and assigns.

“Event of Default” or “event of default” means an occurrence or event specified in and defined as such by Section 9.01 hereof.

“Exempt Facilities” means facilities for the local furnishing of natural gas within the meaning of Section 142(a)(8) of the Code.

“Expiration Date” means the earliest of (i) the stated expiration date of any Liquidity Facility or Letter of Credit and (ii) the date on which the Liquidity Facility or Letter of Credit is terminated pursuant to the terms of the Agreement or the terms of such Liquidity Facility or Letter of Credit.

“Fitch” means Fitch, Inc., doing business as Fitch Ratings, a corporation organized and existing under the laws of the State of Delaware, its successors and their assigns, or, if such entity shall be dissolved or liquidated or shall no longer perform the functions of a securities rating agency, “Fitch” shall be deemed to refer to any other nationally recognized Rating Agency designated by the Borrower, with notice to the Issuer, the Trustee, the Bond Insurer, the Liquidity Provider and the Bank.

“Flexible Rate” means the interest rate on any Bonds established in accordance with Section 2.03(d) hereof.

“Flexible Rate Period” means each period, comprised of Flexible Segments, during which Bonds bear interest at Flexible Rates.

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“Flexible Segment” means, with respect to each Bond bearing interest at a Flexible Rate, the period established in accordance with Section 2.03(d) hereof.

“Force Majeure” means acts of God, strikes, lockouts or other industrial disturbances; acts of public enemies; orders or restraints of any kind of the governments of the United States or of the State, or any of their departments, agencies or officials, or any civil or military authority; insurrections; riots; landslides; lightning; earthquakes; fires; tornadoes; volcanoes; storms; droughts; floods; explosions, breakage, or malfunction or accident to machinery, transmission lines, pipes or canals, even if resulting from negligence; civil disturbances; or any other cause not reasonably within the control of the Borrower.

The term “government obligations” means the obligations described in Section 8.01(B)(a)(iii)(2) hereof.

“Guarantor” means any Person that has guaranteed the obligations of the Borrower under the Agreement or the Reimbursement Agreement.

“Indenture” means this Indenture of Trust, including any indentures supplemental hereto or amendatory hereof.

“Initial Purchasers” means Merrill Lynch, Pierce Fenner & Smith Incorporated, J.P. Morgan Securities Inc. and Wachovia Bank, National Associaton.

“Initial Letter of Credit” means the irrevocable, direct-pay Letter of Credit, in the stated amount of $50,591,781, issued by JPMorgan Chase Bank, N.A. and effective as of the date of delivery of the Bonds.

“Insurer Default” means any of the following events: (i) the Bond Insurer shall fail, wholly or partially, to make a payment when and as required under the provisions of the Bond Insurance; (ii) the Bond Insurance is surrendered, cancelled or terminated, or amended or modified in any material respect, without the Trustee’s prior written consent; (iii) a court of competent jurisdiction enters a final nonappealable judgment that the Bond Insurance is not valid and binding on or enforceable against the Bond Insurer; or (iv) the occurrence and continuation of one or more of the following: (A) the liquidation or dissolution of the Bond Insurer; (B) the commencement by the Bond Insurer of a voluntary case or other proceeding seeking liquidation, reorganization or other relief with respect to itself or its debts under any bankruptcy, insolvency or other similar law now or hereafter in effect, including without limitation the appointment of a trustee, receiver, liquidator, custodian or other similar official for itself or any substantial part of its property; (C) the consent of the Bond Insurer to or the acquiescence by the Bond Insurer in any case or proceeding described in the preceding clause (B) that is commenced against it; (D) the making by the Bond Insurer of an assignment for the benefit of creditors; (E) the failure of the Bond Insurer or the admission by the Bond Insurer in writing of its inability generally to pay its debts or claims as they become due; (F) the initiation by the Bond Insurer of any actions to authorize any of the foregoing; (G) the commencement of an involuntary case or other proceeding against the Bond Insurer seeking liquidation, reorganization or other relief with respect to it or its debts under any bankruptcy, insolvency or other similar law now or hereafter in effect or seeking the appointment of a trustee, receiver, liquidator, custodian or other similar

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official of it or any substantial part of its property, and such involuntary case remaining undismissed and unstayed for a period of 60 days; or (H) the entering of an order for relief against the Bond Insurer under the federal bankruptcy law as now or hereafter in effect.

“Interest Payment Date” means (i) with respect to any Daily Rate Period or Weekly Rate Period, the first Business Day of each calendar month, (ii) with respect to any Term Rate Period, the first Business Day of the sixth calendar month following the effective date of such Term Rate Period and the first Business Day of each successive sixth calendar month, if any, of such Term Rate Period, (iii) with respect to any Flexible Segment, the Business Day succeeding the last day thereof, (iv) with respect to any Auction Rate Period, the Interest Payment Dates set forth in Appendix C, Auction Procedures, attached hereto, and (v) with respect to each Rate Period, the Business Day succeeding the last day thereof.

“Investment Securities” means any of the following: (1) Permitted Investments; (2) obligations, debentures, notes or other evidence of indebtedness issued or guaranteed by any of the following: Farm Credit System Financial Assistance Corporation, Export-Import Bank, Federal Financing Bank, Government National Mortgage Association, Farmers’ Home Administration, or Federal Housing Administration; (3) obligations of any state government the interest on which is exempt from federal income taxation for which a nationally recognized rating service is maintaining a rating within the top two ratings of such rating service; (4) repurchase agreements with reputable financial institutions fully secured by collateral security actually delivered to the Trustee described in clauses (1) or (2) of this definition continuously having a market value at least equal to 102% of the amount so invested and approved in writing by the Bond Insurer, the Bank, S&P, Moody’s and Fitch at the time of such investment; (5) bankers’ acceptances maturing not more than 360 days from the date of issuance issued by a bank (including the Trustee and its affiliates) which are rated at least Aa by Moody’s or rated AA by S&P or Fitch and eligible for purchase by the Federal Reserve Bank; (6) interest-bearing demand or time deposits (including certificates of deposit) in banks (including the Trustee and its affiliates), provided such deposits are (a) secured at all times, and are issued by a bank which has a rating on its short-term certificates of deposit of A-1 or better by S&P, P-1 or better by Moody’s or F-1 or better by Fitch and mature no more than 360 days after the date of purchase or (b) fully insured by Federal deposit insurance; and (7) commercial paper (including both non-interest-bearing discount obligations and interest-bearing obligations payable on demand or on a specified date not more than 270 days after the date of issuance thereof) which have been assigned the rating of at least A-1 or better by S&P, P-1 or better by Moody’s or F-1 or better by Fitch and approved in writing by the Bond Insurer, the Bank and S&P and Moody’s at the time of such investment.

“Issuer” means Clark County, Nevada, as issuer of the Bonds.

“Letter of Credit” means, at any time as applicable, any direct-pay letter of credit, including the Initial Letter of Credit, securing payment of the principal of, interest and premium on the Bonds and the purchase price of the Bonds purchased by the Tender Agent as provided in Article IV during one or more types of Rate Periods, in all cases issued by a Bank, naming the Trustee as beneficiary, delivered with respect to the Bonds pursuant to a Reimbursement Agreement and Section 5.15 of the Agreement, and meeting the requirements of Section 5.15 of the Agreement.

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“Liquidity Facility” means, at any time as applicable, any standby bond purchase agreement or other liquidity facility securing payment of the purchase price of the Bonds purchased by the Tender Agent as provided in Article IV during one or more types of Rate Periods, delivered pursuant to and meeting the requirements of Section 5.14 of the Agreement.

“Liquidity Provider” means, at any time as applicable, any commercial bank, savings association or other financial institution providing a Liquidity Facility then in effect.

“Liquidity Provider Bonds” shall have the meaning ascribed thereto in Section 4.06(b)(i) hereof.

“Maturity Date” means December 1, 2039.

“Moody’s” means Moody’s Investors Service, a corporation organized and existing under the laws of the State of California, its successors and their assigns, and, if such corporation shall be dissolved or liquidated or shall no longer perform the functions of a Rating Agency, “Moody’s” shall be deemed to refer to any other nationally recognized Rating Agency designated by the Borrower, with notice to the Issuer, the Trustee, the Bond Insurer, the Liquidity Provider and the Bank.

“Outstanding” or “outstanding” or “Bonds Outstanding”, in connection with the Bonds means, as of the time in question, all Bonds authenticated and delivered under this Indenture, including, without limitation, Bonds deemed not defeased or satisfied after the payment by the Bond Insurer or the Bank of principal and interest on such Bonds in accordance with Section 8.01 hereof, except:

A. Bonds theretofore canceled or required to be canceled under Section 2.10 or 6.12 hereof;

B. Bonds which are deemed to have been paid in accordance with Article VIII hereof; and

C. Bonds (including Bonds which are deemed to have been purchased pursuant to Section 4.03 hereof) in substitution for which other Bonds have been authenticated and delivered pursuant to Article II hereof.

In determining whether the Owners of a requisite aggregate principal amount of outstanding Bonds have concurred in any request, demand, authorization, direction, notice, consent or waiver under the provisions of this Indenture, Bonds which are owned of record by the Borrower or any affiliate thereof or held by the Trustee for the account of the Borrower shall be disregarded and deemed not to be Outstanding hereunder for the purpose of any such determination (except that, in determining whether the Trustee shall be protected in relying upon any such request, demand, authorization, direction, notice, consent or waiver, only Bonds which a Responsible Officer of the Trustee actually knows to be so owned or held shall be disregarded) unless all Bonds are owned by the Borrower or any affiliate thereof and/or held by the Trustee for the account of the Borrower, in which case such Bonds shall be considered outstanding for the purpose of such determination. For the purpose of this definition, an “affiliate” of any specified Person means any other Person directly or indirectly controlling or controlled by or under direct or indirect

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common control with such specified Person and “control”, when used with respect to any specified Person, means the power to direct the management and policies of such Person, directly or indirectly, whether through the ownership of voting securities, by contract or otherwise; and the terms “controlling” and “controlled” have meanings correlative to the foregoing.

“Owner” is defined under the term “Bondholder.”

“Paying Agent” means, at any time as applicable, the Trustee, acting as paying agent for the Bonds.

“Permitted Investments” means (i) direct obligations of the United States of America (including obligations issued or held in book-entry form on the books of the Department of the Treasury of the United States of America); (ii) obligations the timely payment of the principal of and interest on which are fully guaranteed by the United States of America; (iii) money market funds registered under the Investment Company Act of 1940, as amended, whose shares are registered under the Securities Act of 1933, as amended, which invest only in securities of the type described in clause (i) or (ii) of this definition and having a rating by S&P of at least Aam-G, AAAm or A-1, by Moody’s of at least Aaa or P-1, and by Fitch of at least AAA or F-1; or (iv) certificates or receipts representing direct ownership interests in future interest or principal payments on obligations described in clause (i) or (ii) of this definition which are held by a custodian in safekeeping on behalf of the holders of such certificates or receipts and approved in writing by the Bond Insurer, the Bank, S&P, Moody’s and Fitch at the time of such investments.

“Person” means natural persons, firms, partnerships, associations, corporations, trusts, limited liability companies and public bodies.

“Plans and Specifications” means the plans and specifications for the Project as prepared by the Borrower and heretofore approved by the Issuer.

“Principal Office” means, with respect to the Trustee, the principal corporate trust office of the Trustee, which office at the date of acceptance of the Trustee of the duties and obligations imposed upon it hereunder is located for the purposes and at the addresses specified in Section 13.06 hereof.

“Project” means the facilities to be financed from proceeds of the Bonds, as described in Appendix A to the Agreement.

“Rate Period” means any Daily Rate Period, Weekly Rate Period, Flexible Rate Period, Term Rate Period or Auction Rate Period.

“Rating Agency” means Moody’s, if Moody’s is then rating the Bonds, S&P, if S&P is then rating the Bonds, and Fitch, if Fitch is then rating the Bonds, or any other nationally recognized rating agency then rating the Bonds, if, in each case, such rating has been assigned and is being maintained at the request of the Borrower.

“Rebate Fund” means the fund created by Section 6.14 hereof.

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“Record Date” means with respect to any Interest Payment Date in respect of a Daily Rate Period, a Weekly Rate Period, a Flexible Segment or an Auction Rate Period, the Business Day preceding such Interest Payment Date and, with respect to any Interest Payment Date in respect of a Term Rate Period, the fifteenth day of the calendar month preceding such Interest Payment Date.

“Registrar” means the Trustee, acting as registrar for the Bonds.

“Reimbursement Agreement” means any reimbursement agreement entered into by the Borrower and the Bank in connection with the issuance of any Letter of Credit.

“Remarketing Agent” means, at any time as applicable, the remarketing agent or agents appointed in accordance with Section 4.08 hereof and any permitted successor or successors thereto.

“Reserved Rights” means the right of the Issuer to the payment of costs, expenses and indemnification pursuant to Sections 4.2(d), 4.2(e), 4.2(h) and 6.4 of the Agreement and any rights of the Issuer to receive any notices, certificates, requests, requisitions or other communications, to make inspections and to give consents under the Agreement.

“Resolution” means the resolution duly adopted and approved by the governing body of the Issuer on December 1, 2009, authorizing the issuance and sale of the Bonds and the execution and delivery of this Indenture and the Agreement and the other documents and transactions contemplated herein or therein, and any subsequent resolution relating to any of the Bonds which have not been issued as of the date of such subsequent resolution.

“Responsible Officer” means when used with respect to the Trustee, any officer within the Principal Office of the Trustee including any Vice President, Assistant Vice President, Assistant Treasurer, Trust Officer or any other officer of the Trustee customarily performing functions similar to those performed by the Persons who at the time shall be such officers, respectively, or to whom any corporate trust matter is referred because of such officer’s knowledge of and familiarity with the particular subject and who shall have direct responsibility for the administration of this Indenture.

“Revenues” means the amounts pledged hereunder to the payment of principal of, and premium, if any, and interest on the Bonds, consisting of the following: (i) all amounts payable from time to time by the Borrower under Section 4.2(a) of the Agreement, and all receipts of the Trustee credited under the provisions of this Indenture against said amounts payable, (ii) all amounts received under a Letter of Credit, (iii) any accrued interest on the Bonds deposited with the Trustee under Section 6.03 hereof and (iv) any amounts paid into the Bond Fund from the Construction Fund, including income or revenue derived from the investment of moneys therein.

“S.E.C.” means the Securities and Exchange Commission of the United States of America.

“S&P” means Standard & Poor’s Ratings Group, a division of The McGraw Hill Companies, its successors and their assigns, and, if such Rating Agency shall be dissolved or

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liquidated or shall no longer perform the functions of a Rating Agency, “S&P” shall be deemed to refer to any other nationally recognized Rating Agency designated by the Borrower, with notice to the Issuer, the Trustee, the Bond Insurer, the Liquidity Provider and the Bank.

“Securities Depository” means, with respect to a Book-Entry Bond, DTC or any person, firm, association or corporation constituting a “clearing agency” (securities depository) registered under Section 17A of the Securities Exchange Act of 1934, as amended, which may at any time be substituted in its place to act as Securities Depository for the Bonds, or its successors, or any nominee therefor.

“SIFMA Swap Index” means the SIFMA Municipal Swap Index most recently published in the Bond Buyer , or, if the Bond Buyer no longer publishes such index or is no longer published, the variable rate index published in a comparable periodical selected by the Remarketing Agent.

“State” means the State of Nevada.

“Tax Certificate” means the Tax Certificate and Agreement, dated the date of delivery of the Bonds, executed by the Issuer and the Borrower, as the same may be amended and supplemented from time to time.

“Tax-Exempt” means, with respect to interest on any obligations of a state or local government, including the Bonds, that such interest is excluded from the gross income of the Owners thereof (other than any Owner who is a “substantial user” of facilities financed with such obligations or a “related person” within the meaning of Section 147(a) of the Code for federal income tax purposes, whether or not such interest is includable as an item of tax preference or otherwise includable directly or indirectly for purposes of calculating other tax liabilities, including any alternative minimum tax or environmental tax under the Code.

“Tender Agent” means, at any time as applicable, the Trustee, acting as tender agent for the Bonds.

“Term Bond” means, at any time as applicable, any Bond that bears interest at a Term Rate.

“Term Rate” means the interest rate on the Bonds established in accordance with Section 2.03(c) hereof.

“Term Rate Period” means each period during which the Bonds bear interest at a Term Rate.

“Trust Estate” means the property conveyed to the Trustee pursuant to the Granting Clauses hereof.

“Trustee” means The Bank of New York Mellon Trust Company N.A., and any successor trustee appointed and qualified pursuant to Sections 10.02, 10.06 and 10.09 hereof at the time serving as successor Trustee hereunder.

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“Weekly Rate” means the interest rate on the Bonds established in accordance with Section 2.03(b) hereof.

“Weekly Rate Period” means each period during which Bonds bear interest at Weekly Rates.

SECTION 1.03 NUMBER AND GENDER. The singular form of any word used herein, including the terms defined in Section 1.02, shall include the plural, and vice versa. The use herein of a word of any gender shall include all genders.

SECTION 1.04 CONTENT OF CERTIFICATES AND OPINIONS. Every certificate or opinion with respect to compliance with a condition or covenant provided for in this Indenture or the Agreement shall include (a) a statement that the person or persons making or giving such certificate or opinion have read such covenant or condition and the definitions herein relating thereto; (b) a brief statement as to the nature and scope of the examination or investigation upon which the statements or opinions contained in such certificate or opinion are based; (c) a statement that, in the opinion of the signers, they have made or caused to be made such examination or investigation as is necessary to enable them to express an informed opinion as to whether or not such covenant or condition has been complied with; and (d) a statement as to whether, in the opinion of the signers, such condition or covenant has been complied with.

Any such certificate or opinion made or given by an officer of the Issuer or the Borrower may be based, insofar as it relates to legal matters, upon a certificate or opinion of or representations by counsel, unless such officer knows that the certificate or opinion or representations with respect to the matters upon which his certificate or opinion may be based as aforesaid are erroneous, or in the exercise of reasonable care should have known that the same were erroneous. Any such certificate or opinion made or given by counsel may be based, insofar as it relates to factual matters (with respect to which information is in the possession of the Issuer or the Borrower), upon the certificate or opinion of or representations by an officer of the Issuer or the Borrower, as applicable, unless such counsel knows that the certificate or opinion or representations with respect to the matters upon which his opinion may be based as aforesaid are erroneous, or in the exercise of reasonable care should have known that the same were erroneous. Except as otherwise explicitly stated herein, any opinion required under this Indenture to be delivered by Bond Counsel shall be addressed and delivered, in addition to any other parties identified herein, to the Issuer.

ARTICLE II

THE BONDS

SECTION 2.01 AUTHORIZED AMOUNT OF BONDS. No Bonds may be issued under the provisions of this Indenture except in accordance with this Article. Except as provided in Section 2.08 hereof, the total principal amount of Bonds that may be issued hereunder is hereby expressly limited to $50,000,000. It is hereby recognized that the Issuer and the Borrower have reserved the right to provide for the issuance of other obligations not constituting Bonds pursuant to Section 4.1(b) of the Agreement.

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SECTION 2.02 ISSUANCE OF BONDS.

(a) Authorization of Issuance . The Bonds are hereby authorized to be issued, and upon such issuance the Trustee shall authenticate the Bonds and deliver them as specified in a written request of the Issuer, as more fully provided in Sections 2.06 and 2.12. The Bonds shall be designated “Clark County, Nevada Industrial Development Revenue Bonds (Southwest Gas Corporation Project) Series 2009A.” Unless the Issuer shall otherwise direct, the Bonds shall be numbered A-1 and upward.

(b) General Terms . The Bonds shall be issued as fully registered bonds, without coupons, in Authorized Denominations and shall be dated the Dated Date and shall mature, subject to prior redemption or purchase upon the terms and conditions hereinafter set forth, on the Maturity Date. The Trustee shall insert the date of authentication of each Bond in the place provided for such purpose in the form of the certificate of authentication of the Trustee to be printed on each Bond.

(c) Manner of Payment . The principal of and premium, if any, and interest on the Bonds shall be payable in any coin or currency of the United States of America which, at the respective dates of payment thereof, is legal tender for the payment of public and private debts (which shall be in immediately available funds), and, except as otherwise provided in Section 2.13 hereof with respect to Book-Entry Bonds, such principal and premium, if any, and interest thereon shall be payable at the Principal Office of the Trustee, as Paying Agent. Payment of interest on any Interest Payment Date on any Bond shall be made to the Owner thereof as of the close of business on the Record Date immediately prior thereto and, except as otherwise provided in Section 2.13 hereof with respect to Book-Entry Bonds, shall be (i) made by check or draft of the Trustee, as Paying Agent, mailed on the Interest Payment Date to the Owner as of the close of business on the Record Date immediately preceding the Interest Payment Date, at the Owner’s address as it appears on the registration books of the Issuer kept by the Trustee or at such other address as is furnished to the Trustee in writing by such Owner not later than the close of business on the Record Date for such Interest Payment Date, or (ii) transmitted by wire transfer to the account with a member of the Federal Reserve System located within the continental United States of America of any Owner which owns at least $1,000,000 in aggregate principal amount of the Bonds and which shall have provided wire transfer instructions to the Trustee prior to the close of business on such Record Date, but, in the case of interest payable in respect of a Flexible Segment, only upon presentation of such Bond (if such Bond is not a Book-Entry Bond) at the Principal Office of the Trustee for exchange or transfer in accordance with the provisions hereof, except, in each case, that, if and to the extent that there shall be a default in the payment of the interest due on such Interest Payment Date, such defaulted interest shall be paid to the Owners in whose names any such Bonds are registered at the close of business on the fifth (5th) Business Day preceding the date of payment of such defaulted interest. All payments will be made in immediately available funds.

(d) Interest . The Bonds shall bear interest from and including the Dated Date until payment of the principal or the redemption or purchase price thereof shall have been made or provided for in accordance with the provisions hereof, whether at maturity, upon redemption or otherwise, at the rate or rates per annum determined pursuant to Section 2.03 hereof. Interest on the Bonds shall be paid on each applicable Interest Payment Date and at maturity or prior

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redemption or purchase for the period commencing on the immediately preceding Interest Payment Date (or if no interest has been paid thereon commencing on the Dated Date) to but excluding such Interest Payment Date; provided, however, that if, as shown by the records of the Trustee, interest on the Bonds shall be in default, Bonds shall bear interest from the last date to which interest has been paid in full or duly provided for on the Bonds or, if no interest has been paid or duly provided for on the Bonds, from the Dated Date thereof. Each Bond shall bear interest on overdue principal at the rate borne by the Bonds on the date on which such principal became due and payable. During any Daily Rate Period, Weekly Rate Period or Flexible Rate Period, interest on the related Bonds shall be computed upon the basis of a 365 or 366-day year, as applicable, for the number of days actually elapsed. During any Term Rate Period or any Auction Rate Period of greater than 180 days, interest on the Bonds shall be computed upon the basis of a 360-day year, consisting of twelve (12) thirty (30) day months. During any Auction Rate Period of 180 days or less, interest on the Bonds shall be computed upon the basis of a 360-day year for the number of days actually elapsed.

(e) Proceeds of Sale . The proceeds received by the Issuer from the sale of the Bonds in the amount of $50,000,000 shall be deposited with the Trustee, who shall forthwith deposit such proceeds as set forth in a written request of the Issuer acknowledged by the Borrower. Such request shall provide for such proceeds to be deposited as set forth in this Section, as follows:

(i) to the Costs of Issuance Fund, the sum of $500,000; and

(ii) to the Construction Fund, the balance of such proceeds in the amount of $49,500,000.

SECTION 2.03 DETERMINATION OF RATE PERIODS AND INTEREST RATES. In the manner hereinafter provided, the term of the Bonds will be divided into consecutive Rate Periods during which all Bonds shall bear interest at the Daily Rate, the Weekly Rate, the Flexible Rate, the Term Rate or the Auction Rate, as the case may be. The first Rate Period with respect to the Bonds shall be a Weekly Rate Period commencing on the Dated Date of the Bonds. The Bonds shall bear interest at the rate or rates per annum established from time to time in accordance with the provisions of this Indenture.

(a) (i) Determination of Daily Rate . During each Daily Rate Period, the Bonds shall bear interest at the Daily Rate, which shall be determined by the Remarketing Agent not later than 10:00 a.m., New York time, on each Business Day for such Business Day. The Daily Rate shall be the rate determined by the Remarketing Agent to be the lowest interest rate which would enable the Remarketing Agent to sell such Bonds on the effective date of such rate at a price equal to 100% of the principal amount thereof (without regard to accrued interest); provided, however, that (1) with respect to any day which is not a Business Day, the Daily Rate shall be the Daily Rate determined for the immediately preceding Business Day, and (2) with respect to any other day for which the Remarketing Agent shall not have determined a Daily Rate, the Daily Rate for such day shall be 105% of the most recent SIFMA Swap Index. In no event shall the Daily Rate exceed the lesser of 12% per annum or the maximum rate per annum then permitted by applicable law. The Remarketing Agent shall provide the Trustee with immediate telephonic notice by noon New York time (promptly confirmed in writing) of each

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Daily Rate, as so determined; provided, however that no such notice need be given if the Daily Rate so determined is the same Daily Rate for the immediately preceding day.

(ii) Adjustment to Daily Rate . The Borrower, by written direction to the Issuer, the Trustee, the Liquidity Provider, the Bank, the Remarketing Agent and the Auction Agent, may elect that all (but not less than all) of the Bonds shall bear interest at a Daily Rate. Such direction shall (A) specify the effective date of such adjustment to a Daily Rate, which shall be a Business Day not earlier than the fifteenth (15th) day after the date of such direction (or such shorter period of time to which the Trustee agrees), and shall be (1) in the case of an adjustment from a Term Rate Period, the day immediately following the last day of the then current Term Rate Period or on any day on which the Issuer at the direction of the Borrower would be permitted to redeem such Bonds pursuant to, and at the redemption price described in, Section 3.01(A)(3) hereof, (2) in the case of an adjustment from a Flexible Rate Period, either the day immediately following the last day of the then current Flexible Rate Period or the day immediately following the last day of the last Flexible Segment for each such Bond in the then current Flexible Rate Period all as determined in accordance with Section 2.03(d)(iv) hereof, and (3) in the case of an adjustment from an Auction Rate Period, the day immediately following the end of the then-current Auction Rate Period; (B) be accompanied by a form of Opinion of Bond Counsel to the extent required by the Tax Certificate, together with written evidence of compliance with the terms of Section 5.16 of the Agreement; and (C) specify the Remarketing Agent for the Bonds. During each Daily Rate Period commencing on the date so specified or determined and ending on the day immediately preceding the effective date of the succeeding Rate Period, the interest rate borne by the Bonds shall be a Daily Rate.

(iii) Notice of Adjustment to Daily Rate . Except with respect to an adjustment to a Daily Rate Period from a Flexible Rate, the Trustee shall give notice of an adjustment to a Daily Rate Period to Owners of such Bonds, by first class mail, postage prepaid, not less than twelve (12) days prior to the effective date of such Daily Rate Period. Such notice shall state (1) that the interest rate on such Bonds will be adjusted to a Daily Rate (subject to receipt of the opinion of Bond Counsel referred to in the immediately preceding paragraph (a)(ii) if required, and to the Borrower’s ability to rescind its election as described in Section 2.03(g) hereof), (2) the effective date of such Daily Rate Period, (3) except with respect to an adjustment to a Daily Rate Period from a Weekly Rate Period, in which case the requirements of this subsection (3) shall not apply, that all such Bonds are subject to mandatory purchase on such effective date, and (4) the procedures of such purchase and the payment of the purchase price.

(b) (i) Determination of Weekly Rate . During each Weekly Rate Period, the Bonds shall bear interest at the Weekly Rate, which, in the case of the first Weekly Rate determined for each Weekly Rate Period, shall be determined by the Remarketing Agent not later than 2:00 p.m. New York time on the first day of such Weekly Rate Period and, thereafter, no later than the Business Day preceding each Wednesday during such Weekly Rate Period. The Weekly Rate shall be the rate determined by the Remarketing Agent to be the lowest interest rate which would enable the Remarketing Agent to sell such Bonds on the effective date of such rate at a price equal to 100% of the principal amount thereof (without regard to accrued interest);

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provided, however, that if the Remarketing Agent shall not have determined a Weekly Rate for any period, the Weekly Rate for such period shall be the same as 105% of the most recent SIFMA Swap Index. In no event shall the Weekly Rate exceed the lesser of 12% per annum or the maximum rate per annum then permitted by applicable law. The first Weekly Rate determined for each Weekly Rate Period shall apply to the period commencing on the first day of such period and ending on the succeeding Tuesday. Thereafter, each Weekly Rate shall apply to the period commencing on each Wednesday and ending on the succeeding Tuesday; provided, however, if a Weekly Rate Period shall end on a day other than Tuesday, the last Weekly Rate for such Weekly Rate Period shall apply to the period commencing on the Wednesday preceding the last day of such Weekly Rate Period and ending on such last day. The Remarketing Agent shall provide the Trustee with written notification on the first day of each Weekly Rate Period of each Weekly Rate as so determined.

(ii) Adjustment to Weekly Rate . The Borrower, by written direction to the Issuer, the Trustee, the Liquidity Provider, the Bank, the Remarketing Agent and the Auction Agent, may elect that all (but not less than all) of the Bonds shall bear interest at a Weekly Rate. Such direction shall (A) specify the effective date of such adjustment to a Weekly Rate, which shall be a Business Day not earlier than the 15th day after the date of such direction (or such shorter period of time to which the Trustee agrees) and shall be (1) in the case of an adjustment from a Term Rate Period, the day immediately following the last day of the then current Term Rate Period or on any day on which the Issuer at the direction of the Borrower would be permitted to redeem such Bonds pursuant to, and at the redemption price described in, Section 3.01(A)(3) hereof, (2) in the case of an adjustment from a Flexible Rate Period, either the day immediately following the last day of the then current Flexible Rate Period or the day immediately following the last day of the last Flexible Segment for each such Bond in the then-current Flexible Rate Period, all as determined in accordance with Section 2.03(d)(iv) hereof and (3) in the case of an adjustment from an Auction Rate Period, the day immediately following the end of the then-current Auction Rate Period; (B) be accompanied by a form of Opinion of Bond Counsel to the extent required by the Tax Certificate, together with written evidence of compliance with the terms of Section 5.16 of the Agreement; and (C) specify the Remarketing Agent for the Bonds. During each Weekly Rate Period commencing on the date so specified or determined and ending on the day immediately preceding the effective date of the succeeding Rate Period, the interest rate borne by the Bonds shall be a Weekly Rate.

(iii) Notice of Adjustment to Weekly Rate . Except with respect to an adjustment to a Weekly Rate Period from a Flexible Rate, the Trustee shall give notice of an adjustment to a Weekly Rate Period to Bondholders by first class mail, postage prepaid, not less than twelve (12) days prior to the effective date of such Weekly Rate Period. Such notice shall state (1) that the interest rate on such Bonds will be adjusted to a Weekly Rate (subject to receipt of the opinion of Bond Counsel referred to in the immediately preceding paragraph (b)(ii), if required, and to the Borrower’s ability to rescind its election as described in Section 2.03(g) hereof), (2) the effective date of such Weekly Rate Period, (3) except with respect to an adjustment to a Weekly Rate Period from a Daily Rate Period, in which case the requirements of this subsection (3) shall not

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apply, that all such Bonds are subject to mandatory purchase on such effective date and (4) the procedures of such purchase and the payment of the purchase price.

(c) (i) Determination of Term Rate . During each Term Rate Period (which shall be at least 180 days in duration), the Bonds shall bear interest at the Term Rate determined by the Remarketing Agent on a Business Day selected by the Remarketing Agent, but not more than sixty (60) days prior to the first day of such Term Rate Period. The Term Rate shall be the rate determined by the Remarketing Agent on such date, and filed on such date with the Trustee and the Borrower, by written notice or by telephone promptly confirmed by telecopy or other writing, as being the lowest rate which would enable the Remarketing Agent to sell such Bonds on the effective date of such Term Rate at a price equal to 100% of the principal amount thereof; provided, however, that if, for any reason, a Term Rate for any Term Rate Period shall not be determined or become effective, then the Rate Period for such Bonds shall automatically adjust to a Daily Rate Period. If a Daily Rate for the first day of any such Daily Rate Period is not determined as provided in Section 2.03(a)(i) hereof, the Daily Rate for the first day of such Daily Rate Period shall be 105% of the most recent SIFMA Swap Index. In no event shall any Term Rate exceed the lesser of 12% per annum or the maximum rate per annum then permitted by applicable law.

(ii) Adjustment to or Continuation of Term Rate . The Borrower, by written direction to the Issuer, the Trustee, the Liquidity Provider, the Bank, the Remarketing Agent and the Auction Agent, may elect that all (but not less than all) of the Bonds shall bear, or continue to bear, interest at a Term Rate, and if it shall so elect that such Bonds shall bear or continue to bear, interest at a Term Rate, then the Borrower shall determine the duration of the Term Rate Period during which the Bonds shall bear interest at such Term Rate. As a part of such election, the Borrower also may determine that the initial Term Rate Period shall be followed by successive Term Rate Periods and, if the Borrower so elects, shall specify the duration of each such successive Term Rate Period as provided in this paragraph (ii). Such direction shall (A) specify the effective date of each Term Rate Period, which shall be a Business Day not earlier than the 15th day after the date of such written direction (or such shorter period of time to which the Trustee agrees) and shall be (1) in the case of an adjustment from a Flexible Rate Period, either the day immediately following the last day of the then current Flexible Rate Period or the day immediately following the last day of the last Flexible Segment for such Bond in the then-current Flexible Rate Period, all as determined in accordance with Section 2.03(d)(iv) hereof, (2) in the case of an adjustment from a Term Rate Period, the day immediately following the last day of the then current Term Rate Period or any day on which the Issuer at the direction of the Borrower would be permitted to redeem such Bonds pursuant to, and at the redemption price described in, Section 3.01(A)(3) hereof and (3) in the case of an adjustment from an Auction Rate Period, the day immediately following the end of the then-current Auction Rate Period; (B) specify the last day of such Term Rate Period or, if successive Term Rate Periods shall have been designated, the last day of each such Term Rate Period (which shall be for each Term Rate Period either the date immediately preceding the final maturity date of the Bonds, or a day which both immediately precedes a Business Day and is at least 180 days after the effective date thereof); (C) unless the adjustment is from a Term Rate Period of equal duration, be accompanied by a form of opinion of Bond Counsel to the effect that such adjustment (1)