CFO Transition at Columbia Banking System, Inc.

• Management Change (Item 5.02): Ivan Seda appointed Chief Financial Officer effective December 31, 2025.
• Seda’s initial compensation details:
  • $550,000 annual base salary.
  • Target incentive of 85% of base.
  • Received a $750,000 PSU grant (3-year cliff vest).
• Outgoing CFO Ronald L. Farnsworth transitions to a Senior Advisor role through June 1, 2026.
• Farnsworth is eligible for severance payments upon final separation, contingent on a release of claims, as detailed in the Transition Letter (Exhibit 10