Form 8-K

8-K — COLUMBIA BANKING SYSTEM, INC.

Accession: 0000887343-26-000167

Filed: 2026-07-30

Period: 2026-07-28

CIK: 0000887343

SIC: 6022 (STATE COMMERCIAL BANKS)

Item: Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers: Compensatory Arrangements of Certain Officers

Item: Regulation FD Disclosure

Item: Financial Statements and Exhibits

Documents

8-K — colb-20260728.htm (Primary)

EX-99.1 (colbex991q32026boardofdire.htm)

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8-K

8-K (Primary)

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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 and Exchange Act of 1934

Date of Report: July 28, 2026

(Date of earliest event reported)

Columbia Banking System, Inc.

(Exact Name of Registrant as Specified in Its Charter)

Washington 000-20288 91-1422237

(State or Other Jurisdiction of Incorporation or Organization)

(Commission File Number)

(I.R.S. Employer Identification Number)

1301 A Street

Tacoma, Washington 98402-4200

(address of Principal Executive Offices)(Zip Code)

(253) 305-1900

(Registrant's Telephone Number, Including Area Code)

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 NAME OF EXCHANGE

Common Stock, No Par Value COLB The Nasdaq Stock Market LLC

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 [ ]

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

On July 28, 2026, the Board of Directors of Columbia Banking System, Inc. (the “Company”) appointed Simone Lagomarsino to the Board of Directors of the Company and, subject to approval by the Oregon Department of Consumer and Financial Services Division of Financial Regulation, the Board of Directors of Columbia Bank, the Company’s wholly owned subsidiary, effective as of September 1, 2026 (the “Effective Date”). Ms. Lagomarsino is an audit committee financial expert and at the Effective Date will serve on the Audit Committee and the Enterprise Risk Management Committee of the Company’s Board of Directors.

Ms. Lagomarsino, age 64, served as the President and a member of the board of directors of First Foundation Inc. (NYSE: FFWM) from July 2024 until its sale on April 1, 2026. Prior to joining First Foundation Inc., Ms. Lagomarsino was the President and Chief Executive Officer of Luther Burbank Corporation (Nasdaq: LBC) and its subsidiary Luther Burbank Savings, from January 2019 through February 2024. She also served on the board of directors of Luther Burbank Corporation and Luther Burbank Savings from December 2018 through February 2024. Ms. Lagomarsino served on the board of directors of the Federal Home Loan Bank of San Francisco from January 2013 through December 2024, and during her tenure she chaired the Audit, Risk and Regulatory Compliance Oversight Committees and was Chair of the board during 2022 and 2023. She also served on the board of directors of the Federal Reserve Bank of San Francisco from January 2022 through July 2024. Ms. Lagomarsino has a Bachelor of Arts in Economics from Claremont McKenna College and a Master of Business Administration in Finance from Claremont Graduate School.

There are no arrangements or understandings between Ms. Lagomarsino and any person pursuant to which Ms. Lagomarsino was selected as an officer, and no family relationships exist between Ms. Lagomarsino and any director or executive officer of the Company. Ms. Lagomarsino has received annual payments of $100,000 (the “Deferred Compensation Payments”) under a deferred compensation plan maintained by Heritage Oaks Bank, which was acquired by Pacific Premier Bank in 2017, which was acquired by Columbia Bank in 2025. The Deferred Compensation Payments were initiated in 2017 and will conclude in 2032. Other than the Deferred Compensation Payments, Ms. Lagomarsino is not a party to any transaction, or series of transactions, required to be disclosed pursuant to Item 404(a) of Regulation S-K.

Ms. Lagomarsino will receive compensation for her service on the Board of Directors of the Company and its committees consistent with the Company’s current compensation program for non-employee directors in 2026 (the relevant amounts of which are set forth below), provided that such amounts shall be prorated for the partial year of service commencing on September 1, 2026 and continuing until the next annual meeting of shareholders.

Annual Cash Retainer $95,000

Annual Equity Retainer $115,000

The Annual Equity Retainer comprises a restricted stock award under Columbia’s 2024 Equity Incentive Plan. Such restricted stock award will vest in full on May 14, 2027, consistent with the restricted stock awards previously received by the Company’s current non-employee directors for service on the Company’s Board of Directors in 2026.

Item 7.01 Regulation FD Disclosure.

On July 30, 2026, the Company issued a press release announcing Ms. Lagomarsino’s appointment to the Board of Directors of the Company. A copy of the press release is furnished herewith as Exhibit 99.1 and incorporated into this Item 7.01 by reference.

The information in this Item 7.01 of Form 8-K, including the accompanying Exhibit 99.1, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liability of such section, nor shall such information be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, regardless of the general incorporation language of such filing, except as shall be expressly set forth by specific reference in such filing.

Item 9.01 Financial Statements and Exhibits

(d) Exhibits.

99.1 Press Release of the Company, dated July 30, 2026, regarding Ms. Lagomarsino’s appointment to the Board of Directors

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 hereunto duly authorized.

COLUMBIA BANKING SYSTEM, INC.

(Registrant)

Dated: July 30, 2026

By:/s/ Kumi Yamamoto Baruffi

Kumi Yamamoto Baruffi

Executive Vice President, General Counsel

EX-99.1

Filename: colbex991q32026boardofdire.htm · Sequence: 2

Document

Columbia Banking System Appoints Simone Lagomarsino to its Board of Directors

TACOMA, Wash. (July 30, 2026)—Columbia Banking System, Inc. (Nasdaq: COLB), today announced the appointment of Simone Lagomarsino to its Board of Directors, effective September 1, 2026. Lagomarsino will serve on the Board’s Enterprise Risk Management Committee and Audit Committee.

Lagomarsino is a seasoned financial services executive with more than 40 years of leadership experience across finance, governance and risk management. Most recently, she served as President and Chief Risk Officer of First Foundation Inc. and First Foundation Bank until the company's sale.

“Simone brings deep banking experience, proven executive leadership and a strong understanding of risk, governance and value creation,” said Clint Stein, Chairman, CEO and President of Columbia Banking System. “Her perspective will be a valuable addition to our Board as we continue to strengthen Columbia’s franchise and deliver long-term value for our shareholders.”

Before joining First Foundation, Lagomarsino served as President and Chief Executive Officer of Luther Burbank Corporation and Luther Burbank Savings, where she repositioned the organization for stronger performance, expanded digital marketing capabilities and led the company until its sale. She previously served as President and Chief Executive Officer of the California Bankers Association and as Chief Executive Officer of Heritage Oaks Bancorp, where she delivered top-tier performance and significant growth in assets and earnings.

“Columbia has built one of the West’s most respected banking franchises through disciplined growth and a commitment to prudent risk management,” said Lagomarsino. “I’m honored to be appointed to its Board of Directors and look forward to working with other members and executive leadership to create lasting value for shareholders, customers and communities.”

Lagomarsino’s prior board service includes First Foundation Inc., the Federal Home Loan Bank of San Francisco, Luther Burbank Corporation, Hannon Armstrong Sustainable Infrastructure Capital, Inc., Pacific Premier Bancorp, Inc. and Heritage Oaks Bancorp. She also served on the board of the Federal Reserve Bank of San Francisco. For her leadership and accomplishments, Lagomarsino has received numerous recognitions, including being named “Community Banker of the Year” by American Banker and a “Banking & Finance Visionary” by the Los Angeles Times.

Lagomarsino earned a Bachelor of Arts in Economics from Claremont McKenna College and a Master of Business Administration in Finance from Claremont Graduate School.

About Columbia

Columbia Banking System, Inc. (Nasdaq: COLB) is headquartered in Tacoma, Washington and is the parent company of Columbia Bank, an award-winning western U.S. regional bank. Columbia Bank is the largest bank headquartered in the Northwest and one of the largest banks headquartered in the West with offices in Arizona, California, Colorado, Idaho, Nevada, Oregon, Texas, Utah, and Washington. Columbia Bank combines the resources, sophistication, and expertise of a national bank with a commitment to deliver superior, personalized service. The bank supports consumers and businesses through a full suite of services, including retail and commercial banking, Small Business Administration lending, institutional and corporate banking, and equipment leasing. Columbia Bank customers also have access to comprehensive investment and wealth management expertise as well as healthcare and private banking through Columbia Wealth Management. Learn more at www.columbiabankingsystem.com.

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