Bank of Commerce Holdings (BOCH) Exchange: NASDAQ

Bank of Commerce Holdings is a bank holding company headquartered in Sacramento, California and is the parent company for Merchants Bank of Commerce. The Bank is an FDIC-insured California banking corporation providing community banking and financial services in northern California along the Interstate 5 corridor from Sacramento to Yreka and in the wine region north of San Francisco. The Bank was incorporated as a California banking corporation on November 25, 1981 and opened for business on October 22, 1982. The Company’s common stock is listed on the NASDAQ Global Market and trades under the symbol “BOCH”. As previously announced, on June 23, 2021, the Company entered into an Agreement and Plan of Merger with Columbia Banking System, Inc. (“Columbia”) with Columbia as the surviving entity. The transaction is expected to close during the fourth quarter of 2021, subject to the satisfaction of customary closing conditions, including regulatory and shareholder approvals. Contact Information Randall S. Eslick, President and Chief Executive Officer Telephone Direct (916) 677-5800 James A. Sundquist, Executive Vice President and Chief Financial Officer Telephone Direct (916) 677-5825 Andrea M. Newburn, Vice President and Senior Administrative Officer / Corporate Secretary Telephone Direct (530) 722-3959 Important Information and Where You Can Find It This press release may be deemed to be solicitation material in respect of the proposed merger transaction between Columbia Banking System, Inc. (“Columbia”), and the Company. In connection with the proposed transaction, Columbia filed with the Securities and Exchange Commission (the “SEC”) a registration statement on Form S-4 (Registration No. 333-258551) to register the shares of Columbia’s common stock to be issued in connection with the proposed transaction. The registration statement includes a prospectus of Columbia and a proxy statement of the Company. The registration statement, as amended, was declared effective by the SEC on August 17, 2021, and the proxy statement/prospectus was first mailed to the shareholders of the Company on or about August 18, 2021. SHAREHOLDERS OF THE COMPANY ARE URGED TO READ THE REGISTRATION STATEMENT ON FORM S-4 AND THE PROXY STATEMENT/PROSPECTUS INCLUDED THEREIN, AS WELL AS ANY AMENDMENTS OR SUPPLEMENTS TO THOSE DOCUMENTS, BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT COLUMBIA, THE COMPANY AND THE PROPOSED TRANSACTION.