Columbia Banking System (COLB) Proxy Filing summary

Executive summary

• Completed post-merger integration with Umpqua Holdings, leading to bylaw amendments and elimination of the Executive Chair role ahead of schedule.

• Achieved $82 million in annualized operational savings in 2024, supporting $12 million in reinvestments and realizing $270 million in gross savings since the merger.

• Opened two new branches in Arizona and announced plans for five more in 2025, while net branch count declined by four due to consolidations.

• Enhanced technology platforms, including new payment solutions and CRM tools, to improve customer experience and operational efficiency.

• Net income rose to $534 million in 2024, with improved efficiency ratio and return on equity, despite lower net interest income due to deposit cost pressures.

Voting matters and shareholder proposals

• Shareholders will vote on: (1) election of 11 directors, (2) advisory approval of executive compensation, and (3) ratification of Deloitte & Touche LLP as independent auditor for 2025.

• All director nominees, except the CEO, are independent; two directors are retiring and not standing for re-election.

• Majority of votes cast is required for approval of each proposal; broker non-votes and abstentions have no effect.

Board of directors and corporate governance

• Board size set at 11, with a majority independent and a mandatory retirement age of 75.

• Maria M. Pope appointed as independent Board Chair effective April 1, 2025.

• Board committees (Audit, Compensation, Enterprise Risk Management, Nominating and Governance) are fully independent and conduct annual self-evaluations.

• Board diversity: 38% women, 31% people of color; women chair 60% of board committees.