Columbia Banking System (COLB) Proxy filing summary

Executive summary

• Annual Meeting scheduled for May 14, 2026, with virtual attendance and voting options available for shareholders.

• Shareholders are encouraged to review proxy materials and annual reports online or request copies by April 30, 2026.

Voting matters and shareholder proposals

• Election of eleven directors is proposed, with all nominees recommended by the board.

• Advisory vote on executive compensation (say-on-pay) is included.

• Ratification of Deloitte & Touche LLP as independent auditor for the fiscal year ending December 31, 2026.

• Proxies may vote on other business that arises during the meeting.

Board of directors and corporate governance

• Eleven director nominees are listed for election, reflecting board continuity and governance priorities.