Table of Contents

All references to “Banner” refer to Banner Corporation and those to the “Bank” refer to its wholly-owned subsidiary, Banner Bank. As used throughout this report, the terms “we,” “our,” “us,” or the “Company” refer to Banner Corporation and its consolidated subsidiaries, unless the context otherwise requires.

Certain matters in this Form 10-Q constitute forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements include statements with respect to our beliefs, plans, objectives, goals, expectations, assumptions and statements about future economic performance and projections of financial items, including statements about our financial condition, liquidity and results of operations. Forward-looking statements are not statements of historical fact, are based on certain assumptions and are generally identified by use of the words “believes,” “expects,” “anticipates,” “estimates,” “forecasts,” “intends,” “plans,” “targets,” “potentially,” “probably,” “projects,” “outlook” or similar expressions, or future or conditional verbs such as “may,” “will,” “should,” “would” and “could.” These forward-looking statements are subject to known and unknown risks, uncertainties and other factors that could cause our actual results to differ materially from the results anticipated or implied by our forward-looking statements, including, but not limited to: potential adverse impacts to economic conditions in our local market areas, other markets where the Company has lending relationships, or other aspects of the Company’s business operations or financial markets, including, without limitation, as a result of employment levels, labor shortages and the effects of inflation, a potential recession or slowed economic growth caused by increasing political instability from acts of war including Russia’s invasion of Ukraine, as well as increasing supply chain disruptions;growth; changes in the interest rate environment, including the recentpast increases in the Board of Governors of the Federal Reserve System (the Federal Reserve) benchmark rate and duration at which such increased interest rate levels are maintained, which could adversely affect our revenues and expenses, the value of assets and obligations, and the availability and cost of capital and liquidity; the impact of continuing highelevated inflation and the current and future monetary policies of the Federal Reserve in response thereto; the effects of any federal government shutdown; the credit risks of lending activities, including changes in the level and trend of loan delinquencies and write-offs and changes in estimates of the adequacy of the allowance for credit losses and provisions for credit losses; the ability to manage loan delinquency rates; competitive pressures among financial services companies; changes in consumer spending or borrowing and spending habits; interest rate movements generally and the relative differences between short and long-term interest rates, loan and deposit interest rates, net interest margin and funding sources; the impact of bank failures or adverse developments at other banks and related negative press about the banking industry in general on investor and depositor sentiment; the transition away from the London Interbank Offered Rate (LIBOR) toward new interest rate benchmarks; the impact of repricing and competitors’ pricing initiatives on loan and deposit products; fluctuations in the demand for loans, the number of unsold homes, land and other properties and fluctuations in real estate values; the ability to adapt successfully to technological changes to meet clients’ needs and developments in the marketplace; the ability to access cost-effective funding; the ability to control operating costs and expenses, including the costs associated with our “Banner Forward” initiative;expenses; the use of estimates in determining fair value of certain assets and liabilities, which estimates may prove to be incorrect and result in significant changes in valuation; staffing fluctuations in response to product demand or the implementation of corporate strategies that affect employees, and potential associated charges; disruptions, security breaches or other adverse events, failures or interruptions in, or attacks on, information technology systems or on the third-party vendors who perform critical processing functions; changes in financial markets; changes in economic conditions in general and in Washington, Idaho, Oregon and California in particular; secondary market conditions for loans and the ability to sell loans in the secondary market; the costs, effects and outcomes of litigation; legislation or regulatory changes, including but not limited to changes in regulatory policies and principles, or the interpretation of regulatory capital or other rules, results of safety and soundness and compliance examinations by the Federal Reserve, the Federal Deposit Insurance Corporation (the FDIC), the Washington State Department of Financial Institutions, Division of Banks (the Washington DFI), or other regulatory authorities, including the possibility that any such regulatory authority may, among other things, require restitution or institute an informal or formal enforcement action which could require an increase in reserves for loancredit losses, write-downs of assets or changes in regulatory capital position, or affect the ability to borrow funds, or maintain or increase deposits, or impose additional requirements and restrictions, any of which could adversely affect liquidity and earnings; the availability of resources to address changes in laws, rules, or regulations or to respond to regulatory actions; the quality and composition of our securities portfolio and the impact of adverse changes in the securities markets; the inability of key third-party providers to perform their obligations; changes in accounting principles, policies or guidelines, including additional guidance and interpretation on accounting issues and details of the implementation of new accounting methods; the effects of climate change, severe weather events, natural disasters, pandemics, epidemics and other public health crises, acts of war or terrorism, and other external events on our business; other economic, competitive, governmental, regulatory and technological factors affecting operations, pricing, products and services; future acquisitions by the Company of other depository institutions or lines of business; and future goodwill impairment due to changes in the Company’s business, changes in market conditions; and other risks detailed in our Form 10-K for the year ended December 31, 20222023 (“20222023 Form 10-K”) and in our reports filed with or furnished to the U.S. Securities and Exchange Commission (SEC), including this report on Form 10-Q.

Any forward-looking statements are based upon management’s beliefs and assumptions at the time they are made. We do not undertake and specifically disclaim any obligation to update any forward-looking statements included in this report or the reasons why actual results could differ from those contained in such statements, whether as a result of new information, future events or otherwise. In light of these risks, uncertainties and assumptions, the forward-looking statements discussed in this report might not occur, and you should not put undue reliance on any forward-looking statements.

The accompanying unaudited condensed consolidated financial statements include the accounts of Banner Corporation (the Company or Banner), a bank holding company incorporated in the State of Washington and its wholly-owned subsidiary, Banner Bank (the Bank).

These unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (GAAP) for interim financial information and in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X as promulgated by the SEC.Securities and Exchange Commission (SEC). In preparing these financial statements, the Company has evaluated events and transactions subsequent to September 30, 2023,March 31, 2024, for potential recognition or disclosure. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation of the financial position and results of operations for the periods presented have been included. Certain information and note disclosures have been condensed or omitted pursuant to the rules and regulations of the SEC and the accounting standards for interim financial statements. Certain reclassifications have been made to the 2022 Consolidated Financial Statements and/or schedules to conform to the 2023 presentation. These reclassifications may have affected certain ratios for the prior periods. The effect of these reclassifications is considered immaterial. All significant intercompany transactions and balances have been eliminated.

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect amounts reported in the financial statements. Various elements of the Company’s accounting policies, by their nature, are inherently subject to estimation techniques, valuation assumptions and other subjective assessments.

The information included in this Form 10-Q should be read in conjunction with our Annual Report on Form 10-K for the fiscal year ended December 31, 2022.2023. Interim results are not necessarily indicative of results for a full year or any other interim period.

The ASU is effective for fiscal years,annual periods beginning after December 15, 2023, including interim periods within those fiscal years.2024. Early adoption is permitted for both interim and annual financial statements that have not yet been issued or made available for issuance. If the Company adopts the amendments in an interim period, it should adopt them as of the beginning of the annual period that includes the interim period. The adoption ofamendments should be applied either (1) retrospectively to all prior periods presented in the financial statements or (2) on a prospective basis. The Company has evaluated this ASU isand does not expectedexpect the adoption to have a material impact on the Company’s Consolidated Financial Statements, as the Company does not typically provide these types of awards.

The ASU is effective for annual periods beginning after December 15, 2024. The amendments should be applied on a prospective basis. The Company is evaluating the adoption of this ASU, as it will require additional disclosures in the notes to our Consolidated Financial Statements.

The amortized cost, gross unrealized gains and losses and estimated fair value of securities at September 30, 2023March 31, 2024 and December 31, 20222023 are summarized as follows (in thousands):

Accrued interest receivable on held-to-maturity debt securities was $4.2$3.9 million and $4.8$4.5 million at September 30, 2023March 31, 2024 and December 31, 2022, respectively,2023, and was $11.0$10.7 million and $12.4$10.8 million on available-for-sale debt securities at September 30, 2023March 31, 2024 and December 31, 2022,2023, respectively. Accrued interest receivable on securities is reported in accrued interest receivable on the Consolidated Statements of Financial Condition and is excluded from the calculation of the allowance for credit losses.

At September 30, 2023March 31, 2024 and December 31, 2022,2023, the gross unrealized losses and the fair value for securities available-for-sale aggregated by the length of time that individual securities have been in a continuous unrealized loss position were as follows (in thousands):