Form 11-K AVISTA CORP For: Dec 31

OWNERSHIP PLAN OF

AVISTA CORPORATION

Financial Statements

Attached are the Plan’s financial statements and schedules prepared in accordance with the financial reporting requirements of ERISA.

Exhibits

See Exhibit Index on page 2-1.

2

OF AVISTA CORPORATION

FINANCIAL STATEMENTS AND

SUPPLEMENTAL INFORMATION

YEARS ENDED DECEMBER 31, 2020 AND 2019

3

TABLE OF CONTENTS

4

Report of Independent Registered Public Accounting Firm

Compensation and Organization Committee

Benefit Plans Administration Committee

The Investment and Employee Stock Ownership Plan

  of Avista Corporation

Spokane, Washington

Opinion on the Financial Statements

We have audited the accompanying statements of net assets available for benefits of The Investment and Employee Stock Ownership Plan of Avista Corporation (the Plan) as of December 31, 2020 and 2019, the related statements of changes in net assets available for benefits for the years then ended, and the related notes and schedules (collectively referred to as the financial statements). In our opinion, the financial statements present fairly, in all material respects, the net assets available for benefits of The Investment and Employee Stock Ownership Plan of Avista Corporation as of December 31, 2020 and 2019, and the changes in net assets available for benefits for the years then ended, in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

These financial statements are the responsibility of the Plan’s management. Our responsibility is to express an opinion on the Plan’s financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (PCAOB) and are required to be independent with respect to the Plan in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. The Plan is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our audits, we are required to obtain an understanding of internal control over financial reporting, but not for the purpose of expressing an opinion on the effectiveness of the Plan’s internal control over financial reporting. Accordingly, we express no such opinion.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion.

Supplemental Information

The supplemental schedule of assets (held at end of year) (supplemental information) has been subjected to audit procedures performed in conjunction with the audit of the Plan’s financial statements. The supplemental information is the responsibility of the Plan’s management. Our audit procedures included determining whether the supplemental information reconciles to the financial statements or the underlying accounting and other records, as applicable, and performing procedures to test the completeness and accuracy of the information presented in the supplemental information. In forming our opinion on the supplemental information, we evaluated whether the supplemental information, including its form and content, is presented in conformity with the Department of Labor’s Rules and Regulations for Reporting and Disclosure under the Employee Retirement Income Security Act of 1974. In our opinion, the supplemental information is fairly stated, in all material respects, in relation to the financial statements as a whole.

/s/ CliftonLarsonAllen LLP

We are uncertain as to the year we (or our predecessor firms) began serving consecutively as the auditor of the Plan’s financial statements; however, we are aware that we (or our predecessor firms) have been the Plan’s auditor consecutively since at least 2001.

Phoenix, Arizona

June 10, 2021

5

OF AVISTA CORPORATION

STATEMENTS OF NET ASSETS AVAILABLE FOR BENEFITS

DECEMBER 31, 2020 AND 2019

See accompanying Notes to Financial Statements.

6

OF AVISTA CORPORATION

STATEMENTS OF CHANGES IN NET ASSETS AVAILABLE FOR BENEFITS

YEARS ENDED DECEMBER 31, 2020 AND 2019

See accompanying Notes to Financial Statements.

7

OF AVISTA CORPORATION

NOTES TO FINANCIAL STATEMENTS

DECEMBER 31, 2020 AND 2019

NOTE 1. DESCRIPTION OF THE PLAN

The following description of The Investment and Employee Stock Ownership Plan of Avista Corporation (the Plan) provides only general information. Participants should refer to the Plan document for a more complete description of the Plan’s provisions.

General

Effective January 1, 1984, Avista Corporation (Corporation, Company or Avista) established an Employee Investment Plan under Section 401(k) of the Internal Revenue Code. The Plan, which was restated effective January 1, 2016, and most recently amended effective January 1, 2019, is a defined contribution plan which is subject to the provisions of the Employee Retirement Income Security Act of 1974 (ERISA) and all statutory revisions thereto. The Plan has implemented certain requirements by the Coronavirus Aid, Relief, and Economic Security Act (the CARES Act) and the Setting Every Community Up for Retirement Enhancement Act of 2019 (the SECURE Act). These laws require the Plan to allow certain eligible individuals to receive coronavirus-related relief for loan repayment, suspend required minimum distributions, and delay the commencement date for required minimum distributions, among other changes. The optional features within these acts are currently being assessed but have not been implemented to date. Written amendments to the Plan to reflect these operational changes will be adopted at a later date in accordance with applicable law and IRS guidance. The purpose of this Plan, in which participation is voluntary, is to encourage employees to systematically save a portion of their current compensation and to supplement their savings with contributions from the Corporation. All employees of Avista Corporation are eligible to participate in the Plan after their first pay period following employment. Students, leased employees, and collectively bargained employees (other than collectively bargained employees whose employment is subject to the terms of a collective bargaining agreement which provides for participation in the Plan) are ineligible to participate in the Plan.

Contributions

Plan participants may make contributions during any payroll period for which they receive earnings as eligible employees in an amount at least equal to 1{14cc2b5881a050199a960a1a3483042b446231310e72f0dc471a7a1eddd6b0c3} of their earnings. A participating employee’s annual before-tax contribution was subject to federal limits of $19,500 in 2020 and $19,000 in 2019. Participants who have attained age 50 before the end of the Plan year are eligible to make catch-up contributions. Participants may also contribute amounts representing distributions from other qualified defined benefit or defined contribution plans. Employee contributions represent tax-deferred compensation and Roth 401(k) after tax compensation and may be invested in the employee’s choice of various fund options (each with a different investment objective and risk) in the combination specified by the employee. Employee contributions are made by payroll deduction and transferred to the Plan trustee as soon as practicable following the payroll period in which such amounts are withheld.

Plan participants are automatically enrolled in the Plan upon eligibility at a 3{14cc2b5881a050199a960a1a3483042b446231310e72f0dc471a7a1eddd6b0c3} deferral rate, with an automatic increase of 1{14cc2b5881a050199a960a1a3483042b446231310e72f0dc471a7a1eddd6b0c3} each year up to 15{14cc2b5881a050199a960a1a3483042b446231310e72f0dc471a7a1eddd6b0c3}. Participants can opt out of the Plan at any time. Participants can change their deferral rate at any time.

The Corporation has an obligation to the trust fund for an amount equal to a percentage of employee contributions that is determined by the hire date of the employee.

All non-collectively bargained employees and Local 659 employees hired prior to January 1, 2006, and Local 77 employees hired prior to January 1, 2011, receive a matching contribution of 75{14cc2b5881a050199a960a1a3483042b446231310e72f0dc471a7a1eddd6b0c3} of employee contributions that does not exceed 6{14cc2b5881a050199a960a1a3483042b446231310e72f0dc471a7a1eddd6b0c3} of the employee’s salary.

All non-collectively bargained employees and Local 659 employees hired on or after January 1, 2006, and Local 77 employees hired on or after January 1, 2011, receive a matching contribution of 100{14cc2b5881a050199a960a1a3483042b446231310e72f0dc471a7a1eddd6b0c3} of employee contributions that does not exceed 6{14cc2b5881a050199a960a1a3483042b446231310e72f0dc471a7a1eddd6b0c3} of the employee’s salary.

8

Further, all non-collectively bargained employees hired on or after January 1, 2014, and Local 659 employees hired on or after April 1, 2014, receive an additional non-elective employer contribution based on the employee’s age. The table below illustrates the non-elective contribution rate assigned to the established age groups.

The Company matching contributions are made in the form of cash that is invested as directed by participants from among the investment options offered under the Plan.

Participant Accounts

Each participant’s account is credited with the participant’s contribution and allocations of (a) the Company’s contribution and (b) Plan earnings or losses, and charged with an allocation of administrative expenses. Allocations are based on participant earnings or account balances, as defined. The benefit to which a participant is entitled is the benefit that can be provided from the participant’s vested account.

Vesting

Participant contributions are 100{14cc2b5881a050199a960a1a3483042b446231310e72f0dc471a7a1eddd6b0c3} vested at all times. Participants vest 100{14cc2b5881a050199a960a1a3483042b446231310e72f0dc471a7a1eddd6b0c3} in the Company matching contribution after one year of service or upon death, disability or reaching normal retirement age. Participants vest 100{14cc2b5881a050199a960a1a3483042b446231310e72f0dc471a7a1eddd6b0c3} in the non-elective employer contribution after three years of service or upon death, disability or reaching normal retirement age.

Notes Receivable from Participants

Participants may borrow from their fund accounts a minimum of $1,000 up to a maximum equal to the lesser of $50,000 or 50{14cc2b5881a050199a960a1a3483042b446231310e72f0dc471a7a1eddd6b0c3} of their vested account balance. Principal and interest is paid ratably through payroll deductions. The notes are secured by the balance in the participant’s account and bear interest at a rate of prime rate plus 1{14cc2b5881a050199a960a1a3483042b446231310e72f0dc471a7a1eddd6b0c3}.

Payment of Benefits

Distributions to participants are permitted for termination, retirement, death, disability, or financial hardship. A participant with a financial hardship which imposes an immediate and heavy financial need that cannot be reasonably met by other sources may withdraw a portion of his/her account balance subject to provisions of the Plan. Distributions due to termination shall commence as soon as administratively feasible following the date a participant terminates employment. Distributions may be made in a lump sum, partial lump sum, equal annual installments over a period not to exceed 3 years, or monthly installments over not more than 15 years. If the vested amount is less than $1,000, the account is paid in a lump-sum payment to the participant within a reasonable time frame. If the vested amount is more than $1,000, the participant must consent to the distribution before it may be made.

Forfeited Accounts

At December 31, 2020 and 2019, forfeited non-vested accounts totaled $147,228 and $62,382, respectively. These accounts are used first to restore accounts for returning participants, and then are used to reduce the Company’s obligations to make contributions under the Plan. If there are any excess forfeitures after the Company makes matching contributions, the excess amount may be used to pay administrative expenses under the Plan. In 2020 and 2019, forfeitures in the amount of $9,292 and $105,475 were used to reduce employer contributions.

Voting Rights

Each participant is entitled to exercise voting rights attributable to the shares allocated to his or her account and is notified by the Trustee prior to the time that such rights are to be exercised. The Trustee will vote any shares on which such instructions have not been received, as well as unallocated shares, proportionately in the same manner as Common Stock for which the Trustee has received voting instructions, unless the Trustee determines that to do so would not be consistent with ERISA or a voting participant elects not to have his vote be used in this manner, in which case the Trustee will vote the non-voted or unallocated Common Stock in a manner

9

Table of Contents

consistent with ERISA. Fractional shares will be combined to the largest number of whole shares and voted by the Trustee to the extent possible to reflect the voting direction of whole shares by the participants holding fractional shares.

Diversification

Diversification is offered to participants so that they may have the opportunity to move the value of their investment in the Common Stock into investments which are more diversified. Participants are entitled to make an election to diversify up to 100{14cc2b5881a050199a960a1a3483042b446231310e72f0dc471a7a1eddd6b0c3} of the value of the Common Stock held in their ESOP account.

Basis of Accounting

The accounting records of the Plan are maintained on the accrual basis of accounting in accordance with accounting principles generally accepted in the United States of America.

Use of Estimates

The preparation of financial statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and changes therein, and disclosure of contingent assets and liabilities at the date of the financial statements. Actual results could differ from those estimates.

Investment Valuation and Income Recognition

The Plan’s investments are reported at fair value. Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The Plan’s Benefit Plan Administration Committee (BPAC) determines the Plan’s valuation policies utilizing information provided by the investment advisors and custodian. See Note 3 for discussion of fair value measurements.

Purchases and sales are recorded on a trade-date basis. Interest income is recorded on the accrual basis. Dividends are recorded on the ex-dividend date. Net appreciation includes the Plan’s gains and losses on investments bought and sold as well as held during the year.

Benefit Payments

Benefits are recorded when paid.

Notes Receivable from Participants

Notes receivable from participants are measured at their unpaid principal balance plus any accrued but unpaid interest. Interest income is recorded on the accrual basis. Related fees are recorded as administrative expenses and are expensed when they are incurred. No allowance for credit losses has been recorded as of December 31, 2020 or 2019. If a participant ceases to make note repayments and the Plan administrator deems the participant note to be in default, the participant note balance is reduced and a benefit payment is recorded.

Administrative Expenses

The Plan’s expenses are paid either by the Plan or the Company, as provided by the Plan document. Expenses paid by the Company are excluded from these financial statements. Certain expenses incurred in connection with the general administration of the Plan that are paid by the Plan are recorded as deductions in the accompanying statements of changes in net assets available for benefits. Fees related to the administration of notes receivable from participants and benefit payments are charged directly to the participant’s account and are included in administrative expense.

Subsequent Events

The plan administrator has evaluated events and transactions occurring after the date of the statement of net assets through the date that the financial statements were issued, and noted no other events that were subject to recognition or disclosure.

10

The framework for measuring fair value provides a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable inputs (Level 3). The three levels of the fair value hierarchy are described as follows:

Level 1: Inputs to the valuation methodology are unadjusted quoted prices for identical assets or liabilities in active markets that the Plan has the ability to access.

Level 2: Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly, such as:

If the asset or liability has a specified (contractual) term, the Level 2 input must be observable for substantially the full term of the asset or liability.

Level 3: Inputs to the valuation methodology are unobservable and significant to the fair market value measurement.

The asset’s or liability’s fair value measurement level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. Valuation techniques maximize the use of relevant observable inputs and minimize the use of unobservable inputs.

Following is a description of the valuation methodologies used for assets measured at fair value. There have been no changes in the valuation methodologies used at December 31, 2020 and 2019.

Mutual Funds: Valued at the daily closing price as reported by the fund. Mutual funds held by the Plan are open-end mutual funds that are registered with the Securities and Exchange Commission. These funds are required to publish their daily net asset value (NAV) and to transact at that price. The mutual funds held by the Plan are deemed to be actively traded.

Collective Fund: Valued at the net asset value (NAV) of units of a bank collective trust. NAV is a readily-determinable fair value and is the basis for current transactions. Participant transactions (purchases and sales) may occur daily. If the Plan initiates a full redemption of the collective trust, the issuer reserves the right to temporarily delay withdrawal from the trust in order to ensure that securities liquidations will be carried out in an orderly business manner.

Common Stock: Valued at the closing price reported on the active market on which the individual securities are traded.

Avista Corporation Company Stock Fund: The Avista Corporation Company Stock Fund includes shares of Avista Corporation and cash, and is reported based on unitized value.

Self-Directed Securities: Self-Directed Securities consist of mutual funds and common stocks and are invested at the direction of the participant.

11

The following tables set forth by level, within the fair value hierarchy, the Plan’s assets at fair value as of December 31:

Plan investments in the Avista Corporation Company Stock Fund represented 3.39{14cc2b5881a050199a960a1a3483042b446231310e72f0dc471a7a1eddd6b0c3} and 4.09{14cc2b5881a050199a960a1a3483042b446231310e72f0dc471a7a1eddd6b0c3} of total Plan assets at December 31, 2020 and 2019, respectively. For the year ended December 31, 2020, the Plan’s investment in this fund experienced net depreciation in fair value of approximately $3,500,000 compared to the appreciation of approximately $2,900,000 experienced in 2019.

The Plan invests in various investment securities. Investment securities are exposed to various risks such as interest rate, market, and credit risks. Due to the level of risk associated with certain investment securities, it is at least reasonably possible that changes in the values of the investment securities will occur in the near term and that such changes could materially affect participants’ account balances and the amounts reported in the statements of net assets available for benefits.

Although it has not expressed any intent to do so, the Company has the right under the Plan to discontinue contributions at any time and to terminate the Plan subject to the provisions of ERISA. In the event of Plan termination, the participants would remain 100{14cc2b5881a050199a960a1a3483042b446231310e72f0dc471a7a1eddd6b0c3} vested in their Company contributions.

The Plan is placing reliance on an opinion letter dated May 12, 2017, received from the Internal Revenue Service (IRS) indicating that the Plan is qualified under Section 401 of the Internal Revenue Code (IRC) and is therefore not subject to tax under current income tax law. The Plan administrator believes that the Plan is designed and is currently being operated in compliance with the applicable requirements of the IRC.

Accounting principles generally accepted in the United States of America require Plan management to evaluate tax positions taken by the Plan and recognize a tax liability (or asset) if the Plan has taken an uncertain position that more likely than not would not be sustained upon examination by the IRS. The Plan is subject to routine audits by taxing jurisdictions; however, there are currently no audits for any tax periods in progress.

The Plan investments are managed by Vanguard Fiduciary Trust Company (Vanguard). Vanguard is the trustee as defined by the Plan, and therefore, the investment transactions qualify as party-in-interest transactions. SageView is the investment advisor for the Plan, and fees paid for investment advisory services qualify as party-in-interest transactions. These party-in-interest transactions are exempt from the prohibited transaction rules of ERISA. Fees incurred by the Plan for investment management services and investment advisory services are included in administrative expenses. Certain other expenses of the Plan for recordkeeping, legal and accounting fees are included in administrative expenses. Expenses paid by the Company are not included in the statements of changes in net assets available for benefits.

12

Effective January 1, 2006, the Avista Corporation Company Stock Fund was designated an ESOP. Employer and employee contributions into Avista Corporation stock are classified as ESOP contributions.

13

OF AVISTA CORPORATION

E.I.N. 91-0462470 PLAN NO. 003

SCHEDULE H, LINE 4i — SCHEDULE OF ASSETS (HELD AT END OF YEAR)

DECEMBER 31, 2020

 *  Designates party-in-interest.

**  Cost omitted for participant-directed investments.

14

The Plan. Pursuant to the requirements of the Securities Exchange Act of 1934, the trustees (or other persons who administer the employee benefit plan) have duly caused this annual report to be signed on its behalf by the undersigned hereunto duly authorized.

15

2-1

Exhibit 23

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in Registration Statement No. 333-33790 on Form S-8 of our report dated June 10, 2021 appearing in this Annual Report on Form 11-K of The Investment and Employee Stock Ownership Plan of Avista Corporation for the year ended December 31, 2020.

/s/ CliftonLarsonAllen LLP

Phoenix, Arizona

June 10, 2021