COLUMBIA BANKING SYSTEM, INC.

Regulatory Filings • Nov 14, 2025

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities and Exchange Act of 1934

Date of Report: November 14, 2025

(Date of earliest event reported)

Columbia Banking System, Inc.

(Exact Name of Registrant as Specified in Its Charter)

Washington	000-20288	91-1422237
(State or Other Jurisdiction of Incorporation or Organization)	(Commission File Number)	(I.R.S. Employer Identification Number)

1301 A Street

Tacoma , Washington 98402-4200

(address of Principal Executive Offices) (Zip Code)

( 253 ) 305-1900

(Registrant's Telephone Number, Including Area Code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

[ ☐ ] Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

[ ☐ ] Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

[ ☐ ] Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

[ ☐ ] Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

TITLE OF EACH CLASS	TRADING SYMBOL	NAME OF EXCHANGE
Common Stock, No Par Value	COLB	The Nasdaq Stock Market LLC

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company [ ☐ ]

If an emerging growth company, i ndicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. [ ]

Item 8.01 Other Events.

On November 14, 2025, Columbia Banking System, Inc., parent company of Columbia Bank, announced its Board of Directors has approved a quarterly cash dividend in the amount of $0.37 per common share, representing a 3% increase to the most recent Columbia dividend declaration. The dividend is payable December 15, 2025, to shareholders of record as of November 28, 2025. A copy of the press release is attached hereto as Exhibit 99.1 and is incorporated herein by reference in its entirety.

Item 9.01	Financial Statements and Exhibits
(d)	Exhibits.
	99.1 Press Release Announcing Quarterly Cash Dividend
	104 Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	COLUMBIA BANKING SYSTEM, INC. (Registrant)
Dated: November 14, 2025	By: /s/ Kumi Yamamoto Baruffi Kumi Yamamoto Baruffi Executive Vice President, General Counsel