Fifty-Third Supplemental Indenture



 Exhibit 4.1 
 CONFORMED COPY 
  

 
  

AVISTA CORPORATION 
 TO 
 CITIBANK, N.A. 

As Successor Trustee under 
 Mortgage and Deed of Trust, 
 dated as of June 1, 1939

  
  

Fifty-third Supplemental Indenture 
 Providing among other things for a series of bonds designated 

“First Mortgage Bonds 4.45% Series due 2041” 
 Due December 14, 2041 
  

 
 Dated as of
December 1, 2011 
  
  

 







 FIFTY-THIRD SUPPLEMENTAL INDENTURE 

THIS INDENTURE, dated as of the 1st day of December, 2011, between AVISTA CORPORATION (formerly known as The Washington Water Power Company), a
corporation of the State of Washington, whose post office address is 1411 East Mission Avenue, Spokane, Washington 99202 (the “Company”), and CITIBANK, N.A., formerly First National City Bank (successor by merger to First National
City Trust Company, formerly City Bank Farmers Trust Company), a national banking association incorporated and existing under the laws of the United States of America, whose post office address is 388 Greenwich Street, 14th Floor, New York, New York 10013 (the “Trustee”), as
Trustee under the Mortgage and Deed of Trust, dated as of June 1, 1939 (the “Original Mortgage”), executed and delivered by the Company to secure the payment of bonds issued or to be issued under and in accordance with the provisions
thereof, this indenture (the “Fifty-third Supplemental Indenture”) being supplemental to the Original Mortgage, as heretofore supplemented and amended. 
 WHEREAS pursuant to a written request of the Company made in accordance with Section 103 of the Original Mortgage, Francis M. Pitt (then Individual Trustee under the Mortgage, as supplemented)
ceased to be a trustee thereunder on July 23, 1969, and all of his powers as Individual Trustee have devolved upon the Trustee and its successors alone; and 
 WHEREAS by the Original Mortgage the Company covenanted that it would execute and deliver such further instruments and do such further acts as might be necessary or proper to carry out more effectually
the purposes of the Original Mortgage and to make subject to the lien of the Original Mortgage any property thereafter acquired intended to be subject to the lien thereof; and 
 WHEREAS the Company has heretofore executed and delivered, in addition to the Original Mortgage, the indentures supplemental thereto, and has issued the series of bonds, set forth in Exhibit A hereto
(the Original Mortgage, as supplemented and amended by the First through Fifty-second Supplemental Indentures, being herein sometimes called the “Mortgage”); and 
 WHEREAS the Original Mortgage and the First through Fifty-first Supplemental Indentures have been appropriately filed or recorded in various official records in the States of Washington, Idaho, Montana
and Oregon, as set forth in the First through Fifty-second Supplemental Indentures and the Instrument of Further Assurance, dated December 15, 2001, hereinafter referred to; and 

WHEREAS the Fifty-second Supplemental Indenture, dated as of August 1, 2011, has been appropriately filed or recorded in the various
official records in the States of Washington, Idaho, Montana and Oregon, as set forth in Exhibit B hereto; and 
 WHEREAS for
the purpose of confirming or perfecting the lien of the Mortgage on certain of its properties, the Company has heretofore executed and delivered a Short Form Mortgage and Security Agreement, in multiple counterparts dated as of various dates in
1992, and such instrument has been appropriately filed or recorded in the various official records in the States of Montana and Oregon; and 

  
 2 








 WHEREAS for the purpose of confirming or perfecting the lien of the Mortgage on certain of
its properties, the Company has heretofore executed and delivered an Instrument of Further Assurance dated as of December 15, 2001, and such instrument has been appropriately filed or recorded in the various official records in the States of
Washington, Idaho, Montana and Oregon; and 
 WHEREAS in addition to the property described in the Mortgage the Company has
acquired certain other property, rights and interests in property; and 
 WHEREAS Section 120 of the Original Mortgage, as
heretofore amended, provides that, without the consent of any holders of bonds, the Company and the Trustee, at any time and from time to time, may enter into indentures supplemental to the Original Mortgage for various purposes set forth therein,
including, without limitation, to cure ambiguities or correct defective or inconsistent provisions or to make other changes therein that shall not adversely affect the interests of the holders of bonds of any series in any material respect or to
establish the form or terms of bonds of any series as contemplated by Article II; and 
 WHEREAS Section 8 of the Original
Mortgage, as heretofore amended, provides that the form of each series of bonds (other than the First Series) issued thereunder and of the coupons to be attached to coupon bonds of such series shall be established by Resolution of the Board of
Directors of the Company or by Treasurer’s Certificate, or shall be set forth in an indenture supplemental to the Original Mortgage; that the form of such series, as so established, shall specify the descriptive title of the bonds and various
other terms thereof; and that such series may also contain such provisions not inconsistent with the provisions of the Mortgage as the Company may, in its discretion, cause to be inserted therein expressing or referring to the terms and conditions
upon which such bonds are to be issued and/or secured under the Mortgage; and 
 WHEREAS the Company now desires to create a new
series of bonds; and 
 WHEREAS the execution and delivery by the Company of this Fifty-third Supplemental Indenture and the
terms of the Bonds of the Fifty-fourth Series, hereinafter referred to, have been duly authorized by the Board of Directors of the Company by appropriate Resolutions of said Board of Directors, and all things necessary to make this Fifty-third
Supplemental Indenture a valid, binding and legal instrument have been performed; 

  
 3 








 NOW, THEREFORE, THIS INDENTURE WITNESSETH: That the Company, in consideration of the
premises and of other good and valuable consideration, the receipt and sufficiency whereof are hereby acknowledged, hereby confirms the estate, title and rights of the Trustee (including, without limitation, the lien of the Mortgage on the property
of the Company subjected thereto, whether now owned or hereafter acquired) held as security for the payment of both the principal of and interest and premium, if any, on the bonds from time to time issued under the Mortgage according to their tenor
and effect and the performance of all the provisions of the Mortgage and of such bonds, and, without limiting the generality of the foregoing, hereby confirms the grant, bargain, sale, release, conveyance, assignment, transfer, mortgage, pledge,
setting over and confirmation unto the Trustee, contained in the Mortgage, of all the following described properties of the Company, whether now owned or hereafter acquired, namely: 

All of the property, real, personal and mixed, of every character and wheresoever situated (except any hereinafter or in
the Mortgage expressly excepted) which the Company now owns or, subject to the provisions of Section 87 of the Original Mortgage, may hereafter acquire prior to the satisfaction and discharge of the Mortgage, as fully and completely as if
herein or in the Mortgage specifically described, and including (without in anywise limiting or impairing by the enumeration of the same the scope and intent of the foregoing or of any general description contained in Mortgage) all lands, real
estate, easements, servitudes, rights of way and leasehold and other interests in real estate; all rights to the use or appropriation of water, flowage rights, water storage rights, flooding rights, and other rights in respect of or relating to
water; all plants for the generation of electricity, power houses, dams, dam sites, reservoirs, flumes, raceways, diversion works, head works, waterways, water works, water systems, gas plants, steam heat plants, hot water plants, ice or
refrigeration plants, stations, substations, offices, buildings and other works and structures and the equipment thereof and all improvements, extensions and additions thereto; all generators, machinery, engines, turbines, boilers, dynamos,
transformers, motors, electric machines, switchboards, regulators, meters, electrical and mechanical appliances, conduits, cables, pipes and mains; all lines and systems for the transmission and distribution of electric current, gas, steam heat or
water for any purpose; all towers, mains, pipes, poles, pole lines, conduits, cables, wires, switch racks, insulators, compressors, pumps, fittings, valves and connections; all motor vehicles and automobiles; all tools, implements, apparatus,
furniture, stores, supplies and equipment; all franchises (except the Company’s franchise to be a corporation), licenses, permits, rights, powers and privileges; and (except as hereinafter or in the Mortgage expressly excepted) all the right,
title and interest of the Company in and to all other property of any kind or nature. 
 The property so conveyed
or intended to be so conveyed under the Mortgage shall include, but shall not be limited to, the property set forth in Exhibit C hereto, the particular description of which is intended only to aid in the identification thereof and shall not be
construed as limiting the force, effect and scope of the foregoing. 

  
 4 








 TOGETHER WITH all and singular the tenements, hereditaments and appurtenances belonging or
in anywise appertaining to the aforesaid property or any part thereof, with the reversion and reversions, remainder and remainders and (subject to the provisions of Section 57 of the Original Mortgage) the tolls, rents, revenues, issues,
earnings, income, product and profits thereof, and all the estate, right, title and interest and claim whatsoever, at law as well as in equity, which the Company now has or may hereafter acquire in and to the aforesaid property and franchises and
every part and parcel thereof. 
 THE COMPANY HEREBY CONFIRMS that, subject to the provisions of Section 87 of the Original
Mortgage, all the property, rights, and franchises acquired by the Company after the date thereof (except any hereinbefore or hereinafter or in the Mortgage expressly excepted) are and shall be as fully embraced within the lien of the Mortgage as if
such property, rights and franchises had been owned by the Company at the date of the Original Mortgage and had been specifically described therein. 
 PROVIDED THAT the following were not and were not intended to be then or now or hereafter granted, bargained, sold, released, conveyed, assigned, transferred, mortgaged, pledged, set over or confirmed
under the Mortgage and were, are and shall be expressly excepted from the lien and operation of the Mortgage namely: (l) cash, shares of stock and obligations (including bonds, notes and other securities) not hereafter specifically
pledged, paid, deposited or delivered under the Mortgage or covenanted so to be; (2) merchandise, equipment, materials or supplies held for the purpose of sale in the usual course of business or for consumption in the operation of any
properties of the Company; (3) bills, notes and accounts receivable, and all contracts, leases and operating agreements not specifically pledged under the Mortgage or covenanted so to be; (4) electric energy and other materials or products
generated, manufactured, produced or purchased by the Company for sale, distribution or use in the ordinary course of its business; and (5) any property heretofore released pursuant to any provisions of the Mortgage and not heretofore disposed
of by the Company; provided, however, that the property and rights expressly excepted from the lien and operation of the Mortgage in the above subdivisions (2) and (3) shall (to the extent permitted by law) cease to be so excepted in the
event that the Trustee or a receiver or trustee shall enter upon and take possession of the Mortgaged and Pledged Property in the manner provided in Article XII of the Original Mortgage by reason of the occurrence of a Completed Default as
defined in said Article XII. 
 TO HAVE AND TO HOLD all such properties, real, personal and mixed, granted, bargained,
sold, released, conveyed, assigned, transferred, mortgaged, pledged, set over or confirmed by the Company in the Mortgage as aforesaid, or intended so to be, unto the Trustee, and its successors, heirs and assigns forever. 

IN TRUST NEVERTHELESS, for the same purposes and upon the same terms, trusts and conditions and subject to and with the same provisos and
covenants as set forth in the Mortgage, this Fifty-third Supplemental Indenture being supplemental to the Mortgage. 

  
 5 








 AND IT IS HEREBY FURTHER CONFIRMED by the Company that all the terms, conditions, provisos,
covenants and provisions contained in the Mortgage shall affect and apply to the property in the Mortgage described and conveyed, and to the estates, rights, obligations and duties of the Company and the Trustee and the beneficiaries of the trust
with respect to said property, and to the Trustee and its successors in the trust, in the same manner and with the same effect as if the said property had been owned by the Company at the time of the execution of the Original Mortgage, and had been
specifically and at length described in and conveyed to said Trustee by the Original Mortgage as a part of the property therein stated to be conveyed. 
 The Company further covenants and agrees to and with the Trustee and its successor or successors in such trust under the Mortgage, as follows: 

ARTICLE I 

Fifty-fourth Series of Bonds 
 SECTION 1. (I) There shall be a series of bonds designated “First Mortgage Bonds, 4.45% Series due 2041” (herein sometimes referred to as the “Bonds of the Fifty-fourth Series”),
each of which shall also bear the descriptive title First Mortgage Bond and the form thereof is set forth on Exhibit D hereto. The Bonds of the Fifty-fourth Series shall be issued as fully registered Bonds in denominations of One Thousand
Dollars and, at the option of the Company, any amount in excess thereof (the exercise of such option to be evidenced by the execution and delivery thereof) and shall be dated as in Section 10 of the Original Mortgage provided. The Bonds of the
Fifty-fourth Series shall be limited in aggregate principal amount to $85,000,000 (except for Bonds of such series authenticated and delivered upon transfer of or in exchange for, or in lieu of, other Bonds of such series). 

(II) The Bonds of the Fifty-fourth Series shall mature, bear interest, be payable, be redeemable and be otherwise as set forth below:

 (a) the principal of Bonds of the Fifty-fourth Series shall (unless theretofore paid) be payable on the Stated
Maturity Date (as hereinafter defined); 
 (b) the Bonds of the Fifty-fourth Series shall bear interest at the
rate of four and forty-five one hundredths percentum (4.45%) per annum; interest on such Bonds shall accrue from and including December 14, 2011, except as otherwise provided in the form of bond attached hereto as Exhibit D; interest
on such Bonds shall be payable on each Interest Payment Date and at Maturity (as each of such terms is hereinafter defined); and interest on such Bonds during any period for which payment is made shall be computed on the basis of a 360-day year
consisting of twelve 30-days months; 

  
 6 








 (c) the principal of and premium, if any, and interest on each Bond of the
Fifty-fourth Series payable at Maturity shall be payable upon presentation thereof at the office or agency of the Company in the Borough of Manhattan, The City of New York, in such coin or currency as at the time of payment is legal tender for
public and private debts. The interest on each Bond of the Fifty-fourth Series (other than interest payable at Maturity) shall be payable by check, in similar coin or currency, mailed to the registered owner thereof as of the close of business on
the Record Date (as hereinafter defined) next preceding each Interest Payment Date; provided, however, that if such registered owner shall be a securities depositary, such payment may be made by such other means in lieu of check as shall be agreed
upon by the Company, the Trustee and such registered owner; and, provided, further, that, so long as the Bonds of the Fifty-fourth Series shall be held by an Institutional Investor (as hereinafter defined), payment of principal of and premium, if
any, and interest on the Bonds of the Fifty-fourth Series shall be payable in the manner specified in the Bond Purchase Agreement (as hereinafter defined). 
 (d) The Bonds of the Fifty-fourth Series shall be redeemable in whole at any time, or in part from time to time, at the option of the Company at a redemption price equal to the greater of 

(i) 100% of the principal amount of the Bonds being redeemed, and 

(ii) the sum of the present values of the remaining scheduled payments of principal of and interest (not including any
portion of any scheduled payment of interest which accrued prior to the redemption date) on the Bonds being redeemed discounted to the date of redemption on a semiannual basis (assuming a 360-day year consisting of twelve 30-day months) at a
discount rate equal to the Treasury Yield (as hereinafter defined) plus 50 basis points, 
 plus, in the case of either
(i) or (ii) above, whichever is applicable, accrued interest on such Bonds to the date of redemption. 

(e) (i) “Treasury Yield” means, with respect to any redemption of Bonds of the Fifty-fourth Series, the rate per
annum equal to the semiannual equivalent yield to maturity of the Comparable Treasury Issue, assuming a price for the Comparable Treasury Issue (expressed as a percentage of its principal amount) equal to the Comparable Treasury Price. The Treasury
Yield shall be calculated as of the third business day preceding the redemption date (the “Calculation Date”). 
 (ii) “Comparable Treasury Issue” means the United States Treasury security selected by an Independent Investment Banker as having a maturity comparable to the remaining term of the Bonds of the
Fifty-fourth Series that would be utilized, at the time of selection and in accordance with customary financial practice, in pricing new issues of corporate debt securities of comparable maturity to the remaining term of the Bonds. 

  
 7 








 (iii) “Comparable Treasury Price” means, (A) the average of
the bid and asked prices for the Comparable Treasury Issue (expressed in each case as a percentage of its principal amount) on the Calculation Date, as set forth in the H.15 Daily Update of the Federal Reserve Bank of New York or (B) if such
release (or any successor release) is not published or does not contain such prices on such business day, the Reference Treasury Dealer Quotation for the Calculation Date. 

(iv) “H.15(519)” means the weekly statistical release entitled “Statistical Release H.15 (519)”, or
any successor publication, published by the Board of Governors of the Federal Reserve System. 
 (v) “H.15
Daily Update” means the daily update of H.15(519) available through the worldwide website of the Board of Governors of the Federal Reserve System or any successor site or publication. 

(vi) “Independent Investment Banker” means Merrill Lynch, Pierce, Fenner & Smith Incorporated or, if
so determined by the Company, any other independent investment banking institution of national standing appointed by the Company and reasonably acceptable to the Trustee. 

(vii) “Reference Treasury Dealer Quotation” means, with respect to the Reference Treasury Dealer, the average,
as determined by the Trustee, of the bid and asked prices for the Comparable Treasury Issue (expressed in each case as a percentage of its principal amount and quoted in writing to the Trustee by such Reference Treasury Dealer at 5:00 p.m. on the
Calculation Date). 
 (viii) “Reference Treasury Dealer” means a primary U.S. Government securities
dealer in New York City appointed by the Company and reasonably acceptable to the Trustee. 
 (f) If less than
all of the outstanding Bonds of the Fifty-fourth Series are to be redeemed, the principal amount to be redeemed shall be prorated among all of the holders of such Bonds in the proportion that their respective holdings bear to the aggregate principal
amount of such Bonds outstanding on the date of selection. The portion of any Bond to be redeemed shall be in the principal amount of $1,000 or an integral multiple thereof and such rounding allocations as may be requisite for this purpose shall be
made by the Trustee in its uncontrolled discretion. The Trustee shall promptly notify the Company in writing of the distinctive numbers of the Bond and the portions thereof so selected for redemption. 

  
 8 








 (g) Except as provided in this subsection (II) of Section 1, the Bonds
of the Fifty-fourth Series shall not be redeemable prior to the Stated Maturity Date. 
 (III) (a) At the option of the
registered owner, any Bonds of the Fifty-fourth Series, upon surrender thereof for cancellation at the office or agency of the Company in the Borough of Manhattan, The City of New York, shall be exchangeable for a like aggregate principal amount of
Bonds of the same series of other authorized denominations. 
 The Bonds of the Fifty-fourth Series shall be transferable, upon
the surrender thereof for cancellation, together with a written instrument of transfer in form approved by the registrar duly executed by the registered owner or by his duly authorized attorney, at the office or agency of the Company in the Borough
of Manhattan, The City of New York. 
 Upon any exchange or transfer of Bonds of the Fifty-fourth Series, the Company may make a
charge therefor sufficient to reimburse it for any tax or taxes or other governmental charge, as provided in Section 12 of the Original Mortgage, but the Company hereby waives any right to make a charge in addition thereto or any exchange or
transfer of Bonds of the Fifty-fourth Series; provided, however, that the Company shall not be required to make any transfer or exchange of any Bonds of the Fifty-fourth for a period of 10 days next preceding any selection of such Bonds for
redemption, nor shall it be required to make transfers or exchange of any Bonds of the Fifty-fourth Series which shall have been selected for redemption in whole or in part. 
 The Bonds of the Fifty-fourth Series shall bear a legend as to restrictions on transfer substantially as set forth below: 
 The Bonds evidenced hereby have not been registered under the Securities Act of 1933, as amended (the “Securities Act”) and may not be offered, sold, pledged or otherwise transferred in
contravention of the Securities Act. 
 (IV) For all purposes of this Fifty-third Supplemental Indenture, except as otherwise
expressly provided or unless the context otherwise requires, the terms listed below, when used with respect to the Bonds of the Fifty-fourth Series, shall have the meanings specified below: 

“Bond Purchase Agreement” means the Bond Purchase Agreement, dated October 27, 2011, between the
Company and the purchasers listed on Schedule A thereto. 
 “Business Day” means any day, other
than a Saturday or Sunday, which is not a day on which banking institutions or trust companies in The City of New York, New York are generally authorized or required by law, regulation or executive order to remain closed. 

  
 9 








 “Institutional Investor” means (a) any original
purchaser of a Bond of the Fifty-fourth Series, (b) any holder of a Bond of the Fifty-fourth Series holding (together with one or more of its affiliates) more than $1,000,000 in aggregate principal amount of the Bonds of the Fifty-fourth Series
then outstanding, and (c) any bank, trust company, savings and loan association or other financial institution, any pension plan, any investment company, any insurance company, any broker or dealer, or any other similar financial institution or
entity, regardless of legal form. 
 “Interest Payment Date” means June 1 and
December 1 in each year, commencing June 1, 2012. 
 “Maturity” means the date on
which the principal of the Bonds of the Fifty-fourth Series becomes due and payable, whether at the Stated Maturity Date, upon redemption or acceleration, or otherwise. 

“Record Date”, with respect to any Interest Payment Date, means the close of business on the Business Day
next preceding such Interest Payment Date. 
 “Stated Maturity Date” means December 14,
2041. 
 (V) Notwithstanding the provisions of Section 106 of the Original Mortgage, as amended, the Company shall not
cause any Bonds of the Fifty-fourth Series, or any portion of the principal amount thereof, to be deemed to have been paid as provided in such Section and its obligations in respect thereof to be deemed to be satisfied and discharged prior to the
Maturity thereof unless the Company shall deliver to the Trustee either: 
 (a) an instrument wherein the
Company, notwithstanding the effect of Section 106 of the Original Mortgage, as amended, in respect of such Bonds, shall assume the obligation (which shall be absolute and unconditional) to irrevocably deposit with the Trustee such additional
sums of money, if any, or additional government obligations (meeting the requirements of Section 106), if any, or any combination thereof, at such time or times, as shall be necessary, together with the money and/or government obligations
theretofore so deposited, to pay when due the principal of and premium, if any, and interest due and to become due on such Bonds or portions thereof, all in accordance with and subject to the provisions of Section 106; provided, however, that
such instrument may state that the obligation of the Company to make additional deposits as aforesaid shall be subject to the delivery to the Company by the Trustee of a notice asserting the deficiency accompanied by an opinion of an independent
accountant showing the calculation thereof (which opinion shall be obtained at the expense of the Company); or 

(b) an Opinion of Counsel to the effect that the holders of such Bonds, or portions of the principal amount thereof, will
not recognize income, gain or loss for United States federal income tax purposes as a result of the satisfaction and discharge of the Company’s indebtedness in respect thereof and will be subject to United States federal income tax on the same
amounts, at the same times and in the same manner as if such satisfaction and discharge had not been effected. 

  
 10 









 (VI) Anything in this Supplemental Indenture or the Bonds of the Fifty-fourth Series to the
contrary notwithstanding, any payment of principal of or premium, if any, or interest on any Bond of the Fifty-fourth Series that is due on a date other than a Business Day shall be made on the next succeeding Business Day without including the
additional days elapsed in the computation of the interest payable on such next succeeding Business Day; provided, however, that if the Maturity date of any Bond is a date other than a Business Day, the payment otherwise due at Maturity shall be
made on the next succeeding Business Day and shall include the additional days elapsed in the computation of interest payable on such next succeeding Business Day. 
 (VII) The Bonds of the Fifty-fourth Series shall have such further terms as are set forth in Exhibit D hereto. If there shall be a conflict between the terms of the form of bond and the provisions of the
Mortgage, the provisions of the Mortgage shall control to the extent permitted by law. 
 ARTICLE II 

Outstanding Bonds 
 Upon the delivery of this Fifty-third Supplemental Indenture, Bonds of the Fifty-fourth Series in an aggregate principal amount of $85,000,000 are to be issued and will be Outstanding, in addition to
$1,578,700,000 aggregate principal amount of bonds of prior series Outstanding at the date of delivery of this Fifty-third Supplemental Indenture. 
 ARTICLE III 
 Miscellaneous Provisions 

SECTION 1. The terms defined in the Original Mortgage shall, for all purposes of this Fifty-third Supplemental Indenture, have the
meanings specified in the Original Mortgage. 
 SECTION 2. The Trustee hereby confirms its acceptance of the trusts in the
Original Mortgage declared, provided, created or supplemented and agrees to perform the same upon the terms and conditions in the Original Mortgage set forth, including the following: 

The Trustee shall not be responsible in any manner whatsoever for or in respect of the validity or sufficiency of this Fifty-third
Supplemental Indenture or for or in respect of the recitals contained herein, all of which recitals are made by the Company solely. Each and every term and condition contained in Article XVI of the Original Mortgage, shall apply to and form
part of this Fifty-third Supplemental Indenture with the same force and effect as if the same were herein set forth in full, with such omissions, variations and insertions, if any, as may be appropriate to make the same conform to the provisions of
this Fifty-third Supplemental Indenture. 

  
 11 









 SECTION 3. Whenever in this Fifty-third Supplemental Indenture either of the parties hereto
is named or referred to, this shall, subject to the provisions of Articles XV and XVI of the Original Mortgage be deemed to include the successors and assigns of such party, and all the covenants and agreements in this Fifty-third Supplemental
Indenture contained by or on behalf of the Company, or by or on behalf of the Trustee, or either of them, shall, subject as aforesaid, bind and inure to the respective benefits of the respective successors and assigns of such parties, whether so
expressed or not. 
 SECTION 4. Nothing in this Fifty-third Supplemental Indenture, expressed or implied, is intended, or shall
be construed, to confer upon, or to give to, any person, firm or corporation, other than the parties hereto, the holders of the Bonds Outstanding under the Mortgage, any right, remedy or claim under or by reason of this Fifty-third Supplemental
Indenture or any covenant, condition, stipulation, promise or agreement hereof, and all the covenants, conditions, stipulations, promises and agreements in this Fifty-third Supplemental Indenture contained by or on behalf of the Company shall be for
the sole and exclusive benefit of the parties hereto, and of the holders of the Bonds Outstanding under the Mortgage. 
 SECTION
5. This Fifty-third Supplemental Indenture shall be executed in several counterparts, each of which shall be an original and all of which shall constitute but one and the same instrument. 

SECTION 6. The titles of the several Articles of this Fifty-third Supplemental Indenture shall not be deemed to be any part thereof.

  
  

  
 12 









 IN WITNESS WHEREOF, on the 5th day of December, 2011, AVISTA CORPORATION has caused its corporate
name to be hereunto affixed, and this instrument to be signed and sealed by its President or one of its Vice Presidents, and its corporate seal to be attested by its Corporate Secretary or one of its Assistant Corporate Secretaries for and in its
behalf, all in The City of Spokane, Washington, as of the day and year first above written; and on the 5th day of December, 2011, CITIBANK, N.A., has caused its corporate name to be hereunto affixed, and this instrument to be signed and sealed by its President or one of its Vice Presidents or one of its
Senior Trust Officers or one of its Trust Officers and its corporate seal to be attested by one of its Vice Presidents or one of its Trust Officers, all in The City of New York, New York, as of the day and year first above written. 

 

			
	AVISTA CORPORATION
		
	By:	 	 MARK T. THIES

		 	Name: Mark T. Thies
		 	 Title: Senior Vice President and

            Chief Financial Officer



  

	
	Attest:
	
	     SUSAN Y. FLEMING

	 Name: Susan Y. Fleming
 Title:
Assistant Corporate Secretary

	
	 Executed, sealed and delivered

    by AVISTA CORPORATION

    in the presence of:

	
	     DIANE C. THOREN

	Name: Diane C. Thoren
	
	     RYAN L. KRASSELT

	Name: Ryan L. Krasselt


  
 13 









 
			
	CITIBANK, N.A., AS TRUSTEE
		
	By:	 	     WAFAA ORFY

		 	Name: Wafaa Orfy
		 	Title: Vice President


  

	
	Attest:
	
	     LOUIS PISCITELLI

	 Name: Louis Piscitelli

Title: Vice President

	
	 Executed, sealed and delivered

    by CITIBANK, N.A.,

    as trustee, in the presence of:

	
	     JOHN HANNON

	 Name: John Hannon

	
	     CIRINO EMANUELE

	 Name: Cirino Emanuele



  
 14 










			
	STATE OF WASHINGTON	 	)
		 	) ss.:
	COUNTY OF SPOKANE	 	)

 On the 5th day of December, 2011, before me personally appeared Mark T. Thies, to me known to be a Vice President of AVISTA
CORPORATION, one of the corporations that executed the within and foregoing instrument, and acknowledged said instrument to be the free and voluntary act and deed of said Corporation for the uses and purposes therein mentioned and on oath stated
that he was authorized to execute said instrument and that the seal affixed is the corporate seal of said Corporation. 
 On the 5th
day of December, 2011, before me, a Notary Public in and for the State and County aforesaid, personally appeared Mark T. Thies, known to me to be a Vice President of AVISTA CORPORATION, one of the corporations that executed the within and foregoing
instrument and acknowledged to me that such Corporation executed the same. 
 IN WITNESS WHEREOF, I have hereunto set my hand
and affixed my official seal the day and year first above written. 
  

	
	 RAE AN CORNELL

	Notary Public
	
	RAE AN CORNELL
	Notary Public
	State of Washington
	Commission Expires January 29, 2014



  
 15 










			
	STATE OF NEW YORK	 	)
		 	) ss.:
	COUNTY OF NEW YORK	 	)

 On the 5th day of December, 2011 before me personally appeared Wafaa Orfy, to me known to be a Vice President of CITIBANK, N.A.,
one of the corporations that executed the within and foregoing instrument, and acknowledged said instrument to be the free and voluntary act and deed of said Corporation for the uses and purposes therein mentioned and on oath stated that she was
authorized to execute said instrument and that the seal affixed is the corporate seal of said Corporation. 

On the 5th day of December, 2011, before me, a Notary Public in and for the State and County aforesaid, personally appeared Wafaa
Orfy, known to me to be a Vice President of CITIBANK, N.A., one of the corporations that executed the within and foregoing instrument and acknowledged to me that such Corporation executed the same. 

IN WITNESS WHEREOF, I have hereunto set my hand and affixed my official seal the day and year first above written. 

 

	
	 NOREEN IRIS SANTOS

	Notary Public
	
	NOREEN IRIS SANTOS
	Notary Public, State of New York
	Registration #01SA6228750
	Qualified in Nassau County
	Commission Expires Sept. 27, 2014



  
 16 









 Exhibit A 
 MORTGAGE, SUPPLEMENTAL INDENTURES 
 AND SERIES OF BONDS

  

													
	 MORTGAGE OR
 SUPPLEMENTAL
 INDENTURE
	  	 DATED AS OF
	  	SERIES	  	PRINCIPAL
AMOUNT

ISSUED	 	  	PRINCIPAL
AMOUNT
OUTSTANDING
	  	  	NO.	  	 DESIGNATION
	  	  
	 Original
	  	June 1, 1939	  	1	  	3-1/2% Series due 1964	  	$	22,000,000	  	  	None
	 First
	  	October 1, 1952	  	2	  	3-3/4% Series due 1982	  	 	30,000,000	  	  	None
	 Second
	  	May 1, 1953	  	3	  	3-7/8% Series due 1983	  	 	10,000,000	  	  	None
	 Third
	  	December 1, 1955	  		  	None	  				  	
	 Fourth
	  	March 15, 1957	  		  	None	  				  	
	 Fifth
	  	July 1, 1957	  	4	  	4-7/8% Series due 1987	  	 	30,000,000	  	  	None
	 Sixth
	  	January 1, 1958	  	5	  	4-1/8% Series due 1988	  	 	20,000,000	  	  	None
	 Seventh
	  	August 1, 1958	  	6	  	4-3/8% Series due 1988	  	 	15,000,000	  	  	None
	 Eighth
	  	January 1, 1959	  	7	  	4-3/4% Series due 1989	  	 	15,000,000	  	  	None
	 Ninth
	  	January 1, 1960	  	8	  	5-3/8% Series due 1990	  	 	10,000,000	  	  	None
	 Tenth
	  	April 1, 1964	  	9	  	4-5/8% Series due 1994	  	 	30,000,000	  	  	None
	 Eleventh
	  	March 1 ,1965	  	10	  	4-5/8% Series due 1995	  	 	10,000,000	  	  	None
	 Twelfth
	  	May 1, 1966	  		  	None	  				  	
	 Thirteenth
	  	August 1, 1966	  	11	  	6 % Series due 1996	  	 	20,000,000	  	  	None
	 Fourteenth
	  	April 1, 1970	  	12	  	9-1/4% Series due 2000	  	 	20,000,000	  	  	None
	 Fifteenth
	  	May 1, 1973	  	13	  	7-7/8% Series due 2003	  	 	20,000,000	  	  	None
	 Sixteenth
	  	February 1, 1975	  	14	  	9-3/8% Series due 2005	  	 	25,000,000	  	  	None
	 Seventeenth
	  	November 1, 1976	  	15	  	8-3/4% Series due 2006	  	 	30,000,000	  	  	None


  
 A-1










													
	 MORTGAGE OR
 SUPPLEMENTAL
 INDENTURE
	  	 DATED AS OF
	  	SERIES	  	PRINCIPAL
AMOUNT

ISSUED	 	  	PRINCIPAL
AMOUNT
OUTSTANDING
	  	  	NO.	  	 DESIGNATION
	  	  
	 Eighteenth
	  	June 1, 1980	  		  	None	  				  	
	 Nineteenth
	  	January 1, 1981	  	16	  	14-1/8% Series due 1991	  	 	40,000,000	  	  	None
	 Twentieth
	  	August 1, 1982	  	17	  	15-3/4% Series due 1990-1992	  	 	60,000,000	  	  	None
	 Twenty-First
	  	September 1, 1983	  	18	  	13-1/2% Series due 2013	  	 	60,000,000	  	  	None
	 Twenty-Second
	  	March 1, 1984	  	19	  	13-1/4% Series due 1994	  	 	60,000,000	  	  	None
	 Twenty-Third
	  	December 1, 1986	  	20	  	9-1/4% Series due 2016	  	 	80,000,000	  	  	None
	 Twenty-Fourth
	  	January 1, 1988	  	21	  	10-3/8% Series due 2018	  	 	50,000,000	  	  	None
	 Twenty-Fifth
	  	October 1, 1989	  	22  
 23
	  	 7-1/8% Series due 2013
  

7-2/5% Series due 2016
	  	   

 
	66,700,000  
 17,000,000
	    
   
	  	None  
 None

	 Twenty-Sixth
	  	April 1, 1993	  	24	  	Secured Medium-Term Notes, Series A ($250,000,000 authorized)	  	 	250,000,000	  	  	43,000,000
	 Twenty-Seventh
	  	January 1, 1994	  	25	  	Secured Medium-Term Notes, Series B ($250,000,000 authorized)	  	 	161,000,000	  	  	None
	 Twenty-Eighth
	  	September 1, 2001	  	26	  	Collateral Series due 2002	  	 	220,000,000	  	  	None
	 Twenty-Ninth
	  	December 1, 2001	  	27	  	7.75% Series due 2007	  	 	150,000,000	  	  	None
	 Thirtieth
	  	May 1, 2002	  	28	  	Collateral Series due 2003	  	 	225,000,000	  	  	None
	 Thirty-first
	  	May 1, 2003	  	29	  	Collateral Series due 2004	  	 	245,000,000	  	  	None
	 Thirty-second
	  	September 1, 2003	  	30	  	6.125% Series due 2013	  	 	45,000,000	  	  	None


  
 A-2










													
	 MORTGAGE OR
 SUPPLEMENTAL
 INDENTURE
	  	 DATED AS OF
	  	SERIES	  	PRINCIPAL
AMOUNT

ISSUED	 	  	PRINCIPAL
AMOUNT
OUTSTANDING
	  	  	NO.	  	 DESIGNATION
	  	  
	 Thirty-third
	  	May 1, 2004	  	31	  	Collateral Series due 2005	  	 	350,000,000	  	  	None
	 Thirty-fourth
	  	November 1, 2004	  	32	  	5.45% Series due 2019	  	 	90,000,000	  	  	90,000,000
	 Thirty-fifth
	  	December 1, 2004	  	33	  	Collateral Series 2004A	  	 	88,850,000	  	  	25,000,000
	 Thirty-sixth
	  	December 1, 2004	  	34  
 35
	  	 Collateral Series 2004B
  

Collateral Series 2004C
	  	   

 
	66,700,000  
 17,000,000
	    
   
	  	None  
 None

	 Thirty-seventh
	  	December 1, 2004	  	36	  	Collateral Series 2004D	  	 	350,000,000	  	  	None
	 Thirty-eighth
	  	May 1, 2005	  	37  
 38
	  	 Collateral Series 2005B
  

Collateral Series 2005C
	  	   

 
	66,700,000  
 17,000,000
	    
   
	  	None  
 None

	 Thirty-ninth
	  	November 1, 2005	  	39	  	6.25% Series due 2035	  	   

 
	100,000,000  
 50,000,000
	    
   
	  	100,000,000  
 50,000,000

	 Fortieth
	  	April 1, 2006	  	40	  	Collateral Series due 2011	  	 	320,000,000	  	  	None
	 Forty-first
	  	December 1, 2006	  	41	  	5.70% Series due 2037	  	 	150,000,000	  	  	150,000,000
	 Forty-second
	  	April 1, 2008	  	42	  	5.95% Series due 2018	  	 	250,000,000	  	  	250,000,000
	 Forty-third
	  	November 1, 2008	  	43	  	Collateral Series 2008A	  	 	200,000,000	  	  	None
	 Forty-fourth
	  	December 1, 2008	  	44	  	7.25% Series due 2013	  	 	30,000,000	  	  	None
	 Forty-fifth
	  	December 1, 2008	  	45	  	Collateral Series 2008B	  	 	17,000,000	  	  	None
	 Forty-sixth
	  	September 1, 2009	  	46	  	5.125% Series due 2022	  	 	250,000,000	  	  	250,000,000


  
 A-3










													
	 MORTGAGE OR
 SUPPLEMENTAL
 INDENTURE
	  	 DATED AS OF
	  	SERIES	  	PRINCIPAL
AMOUNT

ISSUED	 	  	PRINCIPAL
AMOUNT
OUTSTANDING
	  	  	NO.	  	 DESIGNATION
	  	  
	 Forty-seventh
	  	September 1, 2009	  	47	  	Collateral Series 2009A	  	 	75,000,000	  	  	None
	 Forty-eighth
	  	December 1, 2010	  	48  
 49
	  	 Collateral Series 2010A
  

Collateral Series 2010B
	  	   

 
	66,700,000  
 17,000,000
	    
   
	  	66,700,000  
 17,000,000

	 Forty-ninth
	  	December 1, 2010	  	50  
 51
	  	 3.89% Series due 2020
  

5.55% Series due 2040
	  	   

 
	52,000,000  
 35,000,000
	    
   
	  	52,000,000  
 35,000,000

	 Fiftieth
	  	December 1, 2010	  	52	  	1.68% Series due 2013	  	 	50,000,000	  	  	50,000,000
	 Fifty-first
	  	February 1, 2011	  	53	  	Collateral Series 2011A	  	 	400,000,000	  	  	400,000,000
	 Fifty-second
	  	August 1, 2011	  		  	None	  				  	


  
 A-4









 Exhibit B 
 FILING AND RECORDING OF 
 FIFTY-SECOND SUPPLEMENTAL INDENTURE

  

							
	FILING IN STATE OFFICES
	 State
	 	 Office of
	 	 Date
	 	 Financing

Statement

Document Number

	 	 	 
	 Washington
	 	Secretary of State	 	10/3/11	 	2011-276-8759-8
	 Idaho
	 	Secretary of State	 	10/3/11	 	B-2011-1098482-9
	 Montana
	 	Secretary of State	 	10/3/11	 	584162965
	 Oregon
	 	Secretary of State	 	10/3/11	 	89016226

  

													
	RECORDING IN COUNTY OFFICES
	  	 	 	 	 Real Estate Mortgage Records
	 	 Financing

Statement

Document

Number

	 County
	 	 Office of
	 	 Date
	 	 Document

Number
	 	 Book
	 	 Page
	 
	 	 	 	 	 	 
	 	 	 	 	 	 
	 Washington
	 		 		 		 		 		 	
	 Adams
	 	Auditor	 	10/3/11	 	299010	 	N/A	 	N/A	 	N/A
	 Asotin
	 	Auditor	 	10/3/11	 	326440	 	N/A	 	N/A	 	N/A
	 Benton
	 	Auditor	 	10/3/11	 	2011-027745	 	N/A	 	N/A	 	N/A
	 Douglas
	 	Auditor	 	10/3/11	 	3154743	 	N/A	 	N/A	 	N/A
	 Ferry
	 	Auditor	 	10/3/11	 	279025	 	N/A	 	N/A	 	N/A
	 Franklin
	 	Auditor	 	10/3/11	 	1772588	 	N/A	 	N/A	 	N/A
	 Garfield
	 	Auditor	 	10/3/11	 	20110475	 	N/A	 	N/A	 	N/A
	 Grant
	 	Auditor	 	10/3/11	 	1291492	 	N/A	 	N/A	 	N/A
	 Klickitat
	 	Auditor	 	10/4/11	 	1095003	 	N/A	 	N/A	 	N/A
	 Lewis
	 	Auditor	 	10/3/11	 	3368800	 	N/A	 	N/A	 	N/A
	 Lincoln
	 	Auditor	 	10/3/11	 	2011-0459257	 	104	 	3663	 	N/A
	 Pend Oreille
	 	Auditor	 	10/3/11	 	20110309765	 	N/A	 	N/A	 	N/A
	 Skamania
	 	Auditor	 	10/3/11	 	2011179169	 	N/A	 	N/A	 	N/A
	 Spokane
	 	Auditor	 	10/3/11	 	6033806	 	N/A	 	N/A	 	N/A
	 Stevens
	 	Auditor	 	10/3/11	 	20110006752	 	N/A	 	N/A	 	N/A
	 Thurston
	 	Auditor	 	10/5/11	 	4231448	 	N/A	 	N/A	 	N/A
	 Whitman
	 	Auditor	 	10/3/11	 	706992	 	N/A	 	N/A	 	N/A
							
	 Idaho
	 		 		 		 		 		 	
	 Benewah
	 	Recorder	 	10/3/11	 	261010	 	N/A	 	N/A	 	N/A
	 Bonner
	 	Recorder	 	10/3/11	 	816127	 	N/A	 	N/A	 	N/A


  
 B-1










													
	 Boundary
	 	Recorder	 	10/3/11	 	252002	 	N/A	 	N/A	 	N/A
	 Clearwater
	 	Recorder	 	10/3/11	 	217704	 	N/A	 	N/A	 	N/A
	 Idaho
	 	Recorder	 	10/3/11	 	481056	 	N/A	 	N/A	 	N/A
	 Kootenai
	 	Recorder	 	10/3/11	 	2329568000	 	N/A	 	N/A	 	N/A
	 Latah
	 	Recorder	 	10/4/11	 	546901	 	N/A	 	N/A	 	N/A

  

													
	RECORDING IN COUNTY OFFICES
	 	 	 	 	 Real Estate Mortgage Records
	 	 Financing

Statement

Document

Number

	 County
	 	 Office of
	 	 Date
	 	 Document

Number
	 	 Book
	 	 Page
	 
	 	 	 	 	 	 
	 	 	 	 	 	 
	
Idaho (cont.)
	 		 		 		 		 		 	
	 Lewis
	 	Recorder	 	10/3/11	 	139814	 	N/A	 	N/A	 	N/A
	 Nez Perce
	 	Recorder	 	10/3/11	 	794696	 	N/A	 	N/A	 	N/A
	 Shoshone
	 	Recorder	 	10/3/11	 	464308	 	N/A	 	N/A	 	N/A
							
	 Montana
	 		 		 		 		 		 	
	 Big Horn
	 	Clerk & Recorder	 	10/6/11	 	344808	 	117	 	897	 	N/A
	 Broadwater
	 	Clerk & Recorder	 	10/3/11	 	166078	 	138	 	825	 	N/A
	 Golden Valley
	 	Clerk & Recorder	 	10/3/11	 	80835	 	M	 	15711	 	N/A
	 Meagher
	 	Clerk & Recorder	 	10/3/11	 	139274	 	N/A	 	N/A	 	N/A
	 Mineral
	 	Clerk & Recorder	 	10/4/11	 	108507	 	N/A	 	N/A	 	N/A
	 Rosebud
	 	Clerk & Recorder	 	10/4/201	 	109082	 	134	 	187	 	N/A
	 Sanders
	 	Clerk & Recorder	 	10/3/11	 	73293	 	N/A	 	N/A	 	N/A
	 Stillwater
	 	Clerk & Recorder	 	10/3/11	 	349091	 	N/A	 	N/A	 	N/A
	 Treasure
	 	Clerk & Recorder	 	10/4/11	 	81635	 	20	 	64	 	N/A
	 Wheatland
	 	Clerk & Recorder	 	10/3/11	 	107027	 	M	 	23277	 	N/A
	 Yellowstone
	 	Clerk & Recorder	 	10/4/11	 	3601207	 	N/A	 	N/A	 	N/A
	 Oregon
	 		 		 		 		 		 	
	 Douglas
	 	Recorder	 	10/3/11	 	2011-014313	 	N/A	 	N/A	 	N/A
	 Jackson
	 	Recorder	 	10/4/11	 	2011-30525	 	N/A	 	N/A	 	N/A
	 Josephine
	 	Recorder	 	10/4/11	 	2011-011347	 	N/A	 	N/A	 	N/A
	 Klamath
	 	Recorder	 	10/4/11	 	2011-011044	 	N/A	 	N/A	 	N/A
	 Morrow
	 	Recorder	 	10/3/11	 	2011-28882	 	N/A	 	N/A	 	N/A
	 Union
	 	Recorder	 	10/4/11	 	20113298	 	N/A	 	N/A	 	N/A
	 Wallowa
	 	Recorder	 	10/3/11	 	66107	 	N/A	 	N/A	 	N/A


  
 B-2









 Exhibit C 
 PROPERTY ADDITIONS 
 First 

THE ADDITIONAL ELECTRIC SUBSTATIONS AND
SUBSTATION SITES OF THE COMPANY, in the States of Idaho and Washington, including all buildings, structures, towers, poles, equipment, appliances and
devices for transforming, converting and distributing electric energy, and the lands of the company on which the same are situated and all of the company’s real estate and interests therein, machinery, equipment, appliances, devices,
appurtenances and supplies, franchises, permits and other rights and other property forming a part of said substations or any of them, or used or enjoyed or capable of being used or enjoyed in connection with any thereof, including, but not limited
to, the following situated in the States of Idaho and Washington, to wit: 
  

	 	1.	Latah County, Idaho: “Deary 115kV Substation”; Property No. ID-1L-033; Grantor: Estate of Gerald E. Johnson; Ptn of NE/4 NW/4 in Section 19, Township 40
North, Range 1 West, B.M. 

  

	 	2.	Spokane County, Washington: “College & Walnut 115kV Substation”; Property No. WA-32-044; Grantor: River Front Properties, LLC; Lots 1, 4 & 5,
portion of Lots 2 & 3, all in Block 8, Chandler’s Second Addition to Spokane Falls, situate in SE/4 of Section 13, Township 25 North, Range 42 East, W.M. 


Second 

ADDITIONAL PROTECTION, MITIGATION AND ENHANCEMENT
PROPERTY of the Company, in the States of Idaho and Montana, real, personal, or mixed, acquired, constructed and/or installed in, on, under and/or proximate to the Company’s Clark Fork hydroelectric development (including,
without limitation, the Cabinet Gorge Hydroelectric Generating Station and the Noxon Rapids Hydroelectric generating Station) for the purpose of protecting and/or enhancing wildlife (including fish and aquatic life), botanical life and/or wetlands,
and/or mitigating any harm or damage thereto, and all other property, real, personal or mixed, used or enjoyed or capable of being used or enjoyed in conjunction therewith, including, but not limited to, the following in the States of Idaho and
Montana, to wit: 
  

	 	1.	Bonner County, Idaho: “Cabinet Gorge Mitigation”: Property No. ID-7B-251; Grantor: Greg S. and Pamela B. Wolf; Portion NE/4, Section 15, Township 57
North, Range 1 East, B.M. 

  

	 	2.	Spokane County, Washington: “Long Lake HED”; Property No. WA-32-257; Grantor: David K. and Reynetta G. Deveau; Portion of SE/4 in Section 30, Township 27
North, Range 40 East, W.M. 


  
 C-1









 Exhibit D 
 (Form of Bond) 
 The Bonds evidenced hereby have not been registered under
the Securities Act of 1933, as amended (the “Securities Act”) and may not be offered, sold, pledged or otherwise transferred in contravention of the Securities Act. 
 PPN 05379B B@5 
 AVISTA CORPORATION 

First Mortgage Bond, 
 4.45% Series due 2041 
  

					
	REGISTERED	  	 	REGISTERED	  
		
	NO.             	  	 	$            	  

 AVISTA CORPORATION, a corporation of the State of Washington (hereinafter called the Company), for
value received, hereby promises to pay to
                                        , or
registered assigns, on December 14, 2041 
 DOLLARS 
 and to pay the registered owner hereof interest thereon semi-annually in arrears on June 1 and December 1 in each year (each such date being hereinafter called an “Interest Payment
Date”), commencing June 1, 2012 and at Maturity (as hereinafter defined), at the rate of four and forty-five one hundredths percentum (4.45%) per annum computed on the basis of a 360-day year consisting of twelve 30-day months, until
the Company’s obligation with respect to the payment of such principal shall have been discharged. This bond shall bear interest from December 14, 2011 or from the most recent Interest Payment Date on or prior to the date of this bond to
which interest on the bonds of this series has been paid. The principal of and premium, if any, and interest on this bond payable at Maturity shall be payable upon presentation hereof at the office or agency of the Company in the Borough of
Manhattan, The City of New York, in such coin or currency of the United States of America as at the time of payment is legal tender for public and private debts. The interest on this bond (other than interest payable at Maturity) shall be paid by
check, in the similar coin or currency, mailed to the registered owner hereof as of the close of business on the Business Day next preceding each Interest Payment Date (each such date being herein called a “Record Date”); provided,
however, that if such registered owner shall be a securities depositary, such payment shall be made by such other means in lieu of check as shall be agreed upon by the Company, the Trustee and such registered owner; and provided further that, so
long as this Bond shall be held by an Institutional Investor (as defined in the Fifty-third Supplemental Indenture referred to below), payment of principal of and premium, if any, and interest on this Bond shall be payable in the manner specified in
the Bond Purchase Agreement (as defined in such Fifty-third Supplemental Indenture). Interest payable at Maturity shall be paid to the person to whom principal shall be paid. As used herein, the term “Maturity” shall mean the date on which
the principal of this bond becomes due and payable, whether at stated maturity, upon redemption or acceleration, or otherwise. 

  
 D-1









 This bond is one of an issue of bonds of the Company issuable in series and is one of a
series known as its First Mortgage Bonds, 4.45% Series due 2041, all bonds of all such series being issued and issuable under and equally secured (except insofar as any sinking or other fund, established in accordance with the provisions of the
Mortgage hereinafter mentioned, may afford additional security for the bonds of any particular series) by a Mortgage and Deed of Trust, dated as of June 1, 1939 (the “Original Mortgage”), executed by the Company (formerly known as The
Washington Water Power Company) to City Bank Farmers Trust Company and Ralph E. Morton, as Trustees (Citibank, N.A., successor Trustee to both said Trustees). The Original Mortgage has been amended and supplemented by various supplemental
indentures, including the Fifty-third Supplemental Indenture, dated as of December 1, 2011 (the “Fifty-third Supplemental Indenture”), and, as so amended and supplemented, is herein called the “Mortgage”. Reference is made
to the Mortgage for a description of the property mortgaged and pledged, the nature and extent of the security, the rights of the holders of the bonds and of the Trustee in respect thereof, the duties and immunities of the Trustee and the terms and
conditions upon which the bonds are and are to be secured and the circumstances under which additional bonds may be issued. If there shall be a conflict between the terms of this bond and the provisions of the Mortgage, the provisions of the
Mortgage shall control to the extent permitted by law. The holder of this bond, by its acceptance hereof, shall be deemed to have consented and agreed to all of the terms and provisions of the Mortgage and, further, in the event that such holder
shall not be the sole beneficial owner of this bond, shall be deemed to have agreed to use all commercially reasonable efforts to cause all direct and indirect beneficial owners of this bond to have knowledge of the terms and provisions of the
Mortgage and of this bond and to comply therewith, including particularly, but without limitation, any provisions or restrictions in the Mortgage regarding the transfer or exchange of such beneficial interests and any legend set forth on this bond.


  
 D-2









 The Mortgage may be modified or altered by affirmative vote of the holders of at least 60%
in principal amount of the bonds outstanding under the Mortgage, considered as one class, or, if the rights of one or more, but less than all, series of bonds then outstanding are to be affected, then such modification or alteration may be effected
with the affirmative vote only of 60% in principal amount of the bonds outstanding of the series so to be affected, considered as one class, and, furthermore, for limited purposes, the Mortgage may be modified or altered without any consent or other
action of holders of any series of bonds. No modification or alteration shall, however, permit an extension of the Maturity of the principal of, or interest on, this bond or a reduction in such principal or the rate of interest hereon or any other
modification in the terms of payment of such principal or interest or the creation of any lien equal or prior to the lien of the Mortgage or deprive the holder of a lien on the mortgaged and pledged property without the consent of the holder hereof.

 The principal hereof may be declared or may become due prior to the stated maturity date on the conditions, in the manner and
at the time set forth in the Mortgage, upon the occurrence of a Completed Default as in the Mortgage provided. 
 As provided in
the Mortgage and subject to certain limitations therein set forth, this bond or any portion of the principal amount hereof will be deemed to have been paid if there has been irrevocably deposited with the Trustee moneys or direct obligations of or
obligations guaranteed by the United States of America, the principal of and interest on which when due, and without regard to any reinvestment thereof, will provide moneys which, together with moneys so deposited, will be sufficient to pay when due
the principal of and premium, if any, and interest on this bond when due. 
 The Mortgage contains terms, provisions and
conditions relating to the consolidation or merger of the Company with or into, and the conveyance or other transfer, or lease, of assets to, another corporation and to the assumption by such other corporation, in certain circumstances, of all of
the obligations of the Company under the Mortgage and on the bonds secured thereby. 
 In the manner prescribed in the Mortgage,
this bond is transferable by the registered owner hereof in person, or by his duly authorized attorney, at the office or agency of the Company in the Borough of Manhattan, The City of New York, upon surrender and cancellation of this bond, together
with a written instrument of transfer whenever required by the Company duly executed by the registered owner or by its duly authorized attorney, and, thereupon, a new fully registered bond of the same series for a like principal amount will be
issued to the transferee in exchange herefor as provided in the Mortgage. The Company and the Trustee may deem and treat the person in whose name this bond is registered as the absolute owner hereof for the purpose of receiving payment and for all
other purposes. 
 In the manner prescribed in the Mortgage, any bonds of this series, upon surrender thereof for cancellation
at the office or agency of the Company in the Borough of Manhattan, The City of New York, are exchangeable for a like aggregate principal amount of bonds of the same series of other authorized denominations. 

  
 D-3









 The bonds of this series shall be redeemable in whole at any time or in part from time to
time, at the option of the Company, upon notice mailed as provided in Section 52 of the Mortgage, at the option of the Company at a redemption price equal to the greater of 

(a) 100% of the principal amount of the bonds being redeemed, and 

(b) the sum of the present values of the remaining scheduled payments of principal of and interest (not including any
portion of any scheduled payment of interest which accrued prior to the redemption date) on the bonds being redeemed discounted to the date of redemption on a semiannual basis (assuming a 360-day year consisting of twelve 30-day months) at a
discount rate equal to the Treasury Yield (as hereinafter defined) plus 50 basis points, 
 plus, in the case of either (a) or
(b) above, whichever is applicable, accrued interest on such Bonds to the date of redemption. 
 “Treasury Yield”
means, with respect to any redemption of the bonds of this series, the rate per annum equal to the semiannual equivalent yield to maturity of the Comparable Treasury Issue, assuming a price for the Comparable Treasury Issue (expressed as a
percentage of its principal amount) equal to the Comparable Treasury Price. The Treasury Yield shall be calculated as of the third business day preceding the redemption date (the “Calculation Date”). 

“Comparable Treasury Issue” means the United States Treasury security selected by an Independent Investment Banker as having a
maturity comparable to the remaining term of the bonds of this series that would be utilized, at the time of selection and in accordance with customary financial practice, in pricing new issues of corporate debt securities of comparable maturity to
the remaining term of the bonds. 
 “Comparable Treasury Price” means, (A) the average of the bid and asked
prices for the Comparable Treasury Issue (expressed in each case as a percentage of its principal amount) on the Calculation Date, as set forth in the H.15 Daily Update of the Federal Reserve Bank of New York or (B) if such release (or any
successor release) is not published or does not contain such prices on such business day, the Reference Treasury Dealer Quotation for the Calculation Date. 
 “H.15(519)” means the weekly statistical release entitled “Statistical Release H.15 (519)”, or any successor publication, published by the Board of Governors of the Federal Reserve
System. 

  
 D-4









 “H.15 Daily Update” means the daily update of H.15(519) available through the
worldwide website of the Board of Governors of the Federal Reserve System or any successor site or publication. 

“Independent Investment Banker” means Merrill Lynch, Pierce, Fenner & Smith Incorporated or, if so determined by the
Company, any other independent investment banking institution of national standing appointed by the Company and reasonably acceptable to the Trustee. 
 “Reference Treasury Dealer Quotation” means, with respect to the Reference Treasury Dealer, the average, as determined by the Trustee, of the bid and asked prices for the Comparable Treasury
Issue (expressed in each case as a percentage of its principal amount and quoted in writing to the Trustee by such Reference Treasury Dealer at 5:00 p.m. on the Calculation Date). 

“Reference Treasury Dealer” means a primary U.S. Government securities dealer in New York City appointed by the Company and
reasonably acceptable to the Trustee. 
 Except as provided above, the bonds of this series are not redeemable prior to their
stated maturity date. 
 No recourse shall be had for the payment of the principal of or premium, if any, or interest on this
bond against any incorporator or any past, present or future subscriber to the capital stock, stockholder, officer or director of the Company or of any predecessor or successor corporation, as such, either directly or through the Company or any
predecessor or successor corporation, under any rule of law, statute or constitution or by the enforcement of any assessment or otherwise, all such liability of incorporators, subscribers, stockholders, officers and directors being released by the
holder or owner hereof by the acceptance of this bond and being likewise waived and released by the terms of the Mortgage. 

This bond shall not become obligatory until Citibank, N.A., the Trustee under the Mortgage, or its successor thereunder, shall have
signed the form of certificate endorsed hereon. 

  
 D-5









 IN WITNESS WHEREOF, AVISTA CORPORATION has caused this bond to be signed in its
corporate name by its President or one of its Vice Presidents by his signature or a facsimile thereof, and its corporate seal to be impressed or imprinted hereon and attested by its Corporate Secretary or one of its Assistant Corporate Secretaries
by his signature or a facsimile thereof. 
  

					
	Dated:	 	AVISTA CORPORATION
			
		 	By:	 	  

		 		 	Name:
		 		 	Title:

  

			
	ATTEST:	 	  

		 	Name:
		 	Title:


  
 D-6









 TRUSTEE’S CERTIFICATE 

This bond is one of the bonds of the series herein designated, described or provided for in the within-mentioned Mortgage. 

 

			
	CITIBANK, N.A.
	             Trustee

		
	 By
	 	  

		 	Authorized Signatory        



  
 D-7