| 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 | 18 Feb 2026 | 0001689701 |
| Type | Sym | Class | Transaction | Value $ | Shares | Change % | * Price $ | Shares After | Date | Ownership | Footnotes |
|---|---|---|---|---|---|---|---|---|---|---|---|
| transaction | COLB | Common Stock | Tax liability | $59,988 | -1,905 | -1.8% | $31.49 | 105,690 | 15 Feb 2026 | Direct | |
| holding | COLB | Common Stock | 3,650 | 15 Feb 2026 | by family trust | ||||||
| holding | COLB | Common Stock | 1,869 | 15 Feb 2026 | by 401(k) |