Material Agreement · New Debt / Obligation

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549   FORM 8-K   CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 14, 2026     AVISTA CORPORATION (Exact name of Registrant as Specified in Its Charter)     Washington 001-03701 91-0462470 (State or Other Jurisdiction of Incorporation) (Commission File Number) (IRS Employer Identification No.)           1411 East Mission Avenue   Spokane , Washington   99202-2600 (Address of Principal Executive Offices)   (Zip Code)   Registrant’s Telephone Number, Including Area Code: 509 489-0500     (Former Name or Former Address, if Changed Since Last Report)   Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions: ☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) ☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) ☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) ☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) Securities registered pursuant to Section 12(b) of the Act: Title of each class   Trading Symbol(s)   Name of each exchange on which registered Common Stock   AVA   The New York Stock Exchange Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter). Emerging growth company ☐ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐   Section 1 - Registrant's Business and Operations Item 1.01 Entry into a Material Definitive Agreement. See Item 2.03 for a discussion of the issuance and sale by the Company of two series of first mortgage bonds.   Section 2 - Financial Information Item 2.03 Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. On May 14, 2026, Avista Corporation (Avista Corp. or the Company) issued and sold $90.0 million of 4.77 percent first mortgage bonds due in 2029 and $70.0 million of 6.10 percent first mortgage bonds due in 2056 pursuant to a bond purchase agreement with institutional investors in the private placement market. The Company expects to issue and sell an additional $70.0 million of 6.10 percent first mortgage bonds under this bond purchase agreement in August 2026. The new first mortgage bonds were issued under and in accordance with the Mortgage and Deed of Trust, dated as of June 1, 1939, from the Company to Citibank, N.A., trustee, as amended and supplemented by various supplemental indentures and other instruments, including the Seventieth Supplemental Indenture, dated as of May 1, 2026 (the “Mortgage”). The new bonds are subject to redemption prior to maturity, at the option of the Company, at a redemption price equal to the principal amount thereof plus a “make-whole” premium and plus accrued interest. In addition, if the Company determines that it is reasonably likely that an original purchaser of bonds of either series is a “specified foreign entity” (as defined in Section 7701 (a)(51)(B) of the Internal Revenue Code of 1986, as amended), the bonds held by such purchaser would be redeemable prior to maturity, at the option of the Company, at a redemption price of 100 percent of the principal amount thereof plus accrued interest. The Mortgage constitutes a lien on substantially all the property of the Company (other than excepted property). The net proceeds from the sale of the new bonds will be used to refinance existing indebtedness and utility capital expenditures. The bonds have not been, and will not be, registered under the Securities Act of 1933 or any state securities laws and may not be offered or sold in the United States absent registration or an applicable exemption from registration requirements. The Mortgage, as previously amended and supplemented, is referred to in and filed as Exhibits 4.1 through 4.70 to the Company’s Annual Report on Form 10-K for the year 2025.   Section 5 – Corporate Governance and Management Item 5.07 Submission of Matters to a Vote of Security Holders. The 2026 Annual Meeting of Shareholders of Avista Corporation (Avista Corp.) was held on May 14, 2026. Four proposals were submitted to shareholders as disclosed in Avista Corp.'s Definitive Proxy Statement filed on April 1, 2026, three of which were approved. There were 82,359,072 shares of common stock issued and outstanding as of March 13, 2026, the record date, with 72,287,745 shares represented at the meeting. The proposals and the results of the voting are as follows: Proposal 1: Election of eleven directors, for one-year terms expiring at the 2027 Annual Meeting of Shareholders, and until their successors are elected. Director   For     Against     Abstain     Broker Non-Votes   Julie A. Bentz     65,044,528       262,432       141,220       6,839,565   Donald C. Burke     63,703,512       1,590,088       154,580       6,839,565   Kevin B. Jacobsen     64,985,237       308,391       154,552       6,839,565   Rebecca A. Klein     64,058,130       1,249,310       140,740       6,839,565   Sena M. Kwawu     64,992,991       302,410       152,779       6,839,565   Scott H. Maw     64,086,499       1,202,858       158,823       6,839,565   Scott L. Morris     63,739,971       1,552,127       156,082       6,839,565   Jeffry L. Philipps     64,934,330       352,405       161,445       6,839,565   Heather L. Rosentrater     64,655,105       651,224       141,851       6,839,565   Heidi B. Stanley     63,734,859       1,563,792       149,529       6,839,565   Janet D. Widmann     58,951,492       6,351,486       145,202       6,839,565   All directors were elected since the number of votes cast “for” each nominee exceeded the number of votes “against.” Abstentions and broker non-votes had no effect on the election.   Proposal 2: Ratification of the appointment of Deloitte & Touche LLP as the Company's independent registered public accounting firm for 2026. For     Against     Abstain     Broker Non-Votes   69,874,464       2,281,840       131,441     N/A This proposal was approved as the number of votes cast “for” exceeded the number of votes “against.” Abstentions had no effect on the outcome.   Proposal 3: Advisory (non-binding) vote on executive compensation. For     Against     Abstain     Broker Non-Votes     62,854,984       2,274,875       318,321       6,839,565   This advisory (non-binding) resolution was approved as the number of votes cast “for” exceeded the number of votes “against.” Abstentions and broker non-votes had no effect on the outcome. Proposal 4: Amendment of the Restated Articles of Incorporation to reduce the shareholder approval requirement for specified matters from 80% of the total number of shares of common stock outstanding to a majority of such shares outstanding. For     Against     Abstain     Broker Non-Votes     64,317,253       805,879       325,048       6,839,565   This proposal was not approved as it did not receive the affirmative vote of the holders of 80 percent of the issued and outstanding shares of Avista Corp. common stock. Abstentions and broker non-votes had the same effect as negative votes.   Item 9.01 Financial Statements and Exhibits. (d) Exhibits 4.1 Seventieth Supplemental Indenture to the Mortgage dated as of May 1, 2026 104 Cover Page Interactive Data File  (embedded within the Inline XBRL document)   SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.       Avista Corporation       (Registrant)         Date: May 19, 2026 By: /s/ Kevin J. Christie       Kevin J. Christie Senior Vice President, Chief Financial Officer, Treasurer and Regulatory Affairs Officer