Form 4 Filing for Luis Machuca

Luis Machuca, a director at Columbia Banking System, Inc. (COLB), acquired 659 shares of Deferred Compensation Phantom Stock on March 16, 2026. The shares were accrued under the company's deferred compensation plan and will be paid out after the termination of his employment. The transaction value was $26.83 per share, with a total of 48,403 shares now held following the transaction. The phantom stock is linked to the company's Common stock.