Torran B. Nixon - 03 Mar 2026 Form 4 Insider Report for COLUMBIA BANKING SYSTEM, INC. (COLB)

Signature
/s/ Andrea M. Newburn, Attorney-in-fact
Issuer symbol
COLB
Transactions as of
03 Mar 2026
Net transactions value
-$127,932
Form type
4
Filing time
05 Mar 2026, 16:27:54 UTC
Previous filing
02 Mar 2026

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Nixon Torran B Senior Executive VP C/O COLUMBIA BANKING SYSTEM, INC., 1301 A STREET, TACOMA /s/ Andrea M. Newburn, Attorney-in-fact 05 Mar 2026 0001689701

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction COLB Common Stock Sale $63,308 -2,241 -2.2% $28.25 100,469 03 Mar 2026 Direct F1
transaction COLB Common Stock Sale $64,624 -2,240 -2.2% $28.85 98,229 04 Mar 2026 Direct F1
holding COLB Common Stock 3,650 03 Mar 2026 by family trust
holding COLB Common Stock 1,876 03 Mar 2026 by 401(k)
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Buy Plan / Sale Plan: These are also open market purchases/sales of shares, but in this case the transaction is part of a trading plan. Rule 10b5-1 allows insiders to setup a trading plan to buy/sell stocks over a certain period of time. Since the purchases/sales are predetermined, this protects the insiders from violating insider trading law.

Transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

Explanation of Responses:

Id Content
F1 Open market sale pursuant to a 10B5-1 Plan which was established by Reporting Person on November 25, 2025, in accordance with Rule 10B5-1 of the Securities Exchange Act of 1934, as amended.