BANNER CORP — Board/Management Information 2026

Mar 2, 2026

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 EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): March 2, 2026

Banner Corporation

(Exact name of registrant as specified in its charter)

Washington	000-26584	91-1691604
(State or other jurisdiction of incorporation)	(Commission File Number)	(I.R.S. Employer Identification No.)

10 S. First Avenue, Walla Walla , Washington 99362

(Address of principal executive offices) (Zip Code)

Registrant's telephone number (including area code) ( 509 ) 527-3636

Not Applicable

(Former name or former address, if changed since last report)

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(s)	Name of each exchange on which registered
Common Stock, par value $.01 per share	BANR	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, indicate 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 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

(d) Appointment of New Directors

On February 25, 2026, the Board of Directors (the “Board”) of Banner Corporation (the “Company”) appointed Monica B. O’Reilly and Judith A. Steiner as directors of the Company, effective as of March 1, 2026. Ms. O’Reilly will serve on the Corporate Governance/Nominating and Risk Committees of the Board. Ms. Steiner will serve on the Credit Risk and Risk Committees of the Board. In addition, Ms. O’Reilly and Ms. Steiner were elected to the Board of Directors of Banner Bank (the “Bank”), the Company’s wholly owned banking subsidiary.

The Board affirmatively determined that Ms. O’Reilly and Ms. Steiner each qualifies as an “independent director” in accordance with NASDAQ listing standards. Additionally, neither Ms. O’Reilly nor Ms. Steiner has an interest in any transactions requiring disclosure under Item 404(a) of Regulation S-K, and there are no family relationships between Ms. O’Reilly or Ms. Steiner or with any of the Company’s other directors or executive officers. Other than the compensation arrangements described below, there are no arrangements or understandings between Ms. O’Reilly or Ms. Steiner and any other persons or entities pursuant to which they have been elected as a director.

Ms. O’Reilly and Ms. Steiner will be compensated for their services as a director consistent with the Company’s standard practices for non-employee directors. Ms. O’Reilly and Ms. Steiner will each receive an annual cash retainer of $55,000 and an award of restricted stock units (“RSUs”) with a grant date fair value of $65,000. In addition, Ms. O’Reilly and Ms. Steiner will receive an additional annual cash retainer for each Board committee on which they serve. Cash and equity-based director compensation will be prorated for partial periods of service.

In connection with the election of Ms. O’Reilly and Ms. Steiner as directors of the Company, the Board increased the number of directors comprising the Board from 12 to 13 directors, effective March 1, 2026.

For additional information concerning Ms. O’Reilly’s and Ms. Steiner’s backgrounds, please refer to the press release dated March 2, 2026, which is attached hereto as Exhibit 99.1 and incorporated herein by reference.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits

99.1 Press Release of Banner Corporation dated March 2, 2026.

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.

	BANNER CORPORATION
Date: March 2, 2026	By: /s/ Mark J. Grescovich
	Mark J. Grescovich
	President and Chief Executive Officer