Columbia Banking director proposes $329K share sale

Fidelity Brokerage Services LLC is named as broker, with October 29, 2026, listed as the approximate sale date.

Rhea-AI Filing Summary

Columbia Banking System, Inc. (COLB) director Steven R. Gardner filed notice of a proposed sale of 10,522 common shares, with an aggregate market value of $328,616.53, through Fidelity Brokerage Services LLC. The notice lists October 29, 2026, as the approximate sale date. It attributes the shares to open-market purchases of 180 shares on August 1, 2011, 1,650 shares on August 4, 2011, and 8,692 shares on October 3, 2024.

Key Figures

Common shares proposed for sale: 10,522 shares Aggregate market value: $328,616.53 Shares outstanding: 282,902,268 shares +3 more

6 metrics

Common shares proposed for sale 10,522 shares Approximate sale date: October 29, 2026

Aggregate market value $328,616.53 Proposed sale

Shares outstanding 282,902,268 shares Number listed in the securities information

Shares acquired 180 shares Open-market purchase on August 1, 2011

Shares acquired 1,650 shares Open-market purchase on August 4, 2011

Shares acquired 8,692 shares Open-market purchase on October 3, 2024

Key Terms

Rule 144, Open Market Purchase, attorney-in-fact

3 terms

Rule 144 regulatory

"paragraph (a) of Rule 144"

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

Open Market Purchase financial

"Open Market Purchase"

An open market purchase is when a company buys its own shares on public stock exchanges the same way any investor would, rather than through a private deal. Investors care because these purchases reduce the number of shares available, can boost earnings per share and share price, signal that management thinks the stock is undervalued, and use company cash that might otherwise go to reinvestment or dividends — like a business quietly buying back its own tickets at the box office.

attorney-in-fact regulatory

"as attorney-in-fact for Steven R. Gardner"

An attorney-in-fact is the person or entity given legal authority through a power of attorney to act on behalf of another for specific tasks, such as signing documents, voting shares, or handling transactions. For investors, this matters because it lets a trusted representative make timely decisions or complete paperwork when the owner cannot, much like handing keys to someone to run errands on your behalf—so checks on scope and limits of that authority are important.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What shares does Steven R. Gardner plan to sell in COLB?

Steven R. Gardner, identified as a director, submitted notice of a proposed sale of 10,522 common shares with an aggregate market value of $328,616.53. Fidelity Brokerage Services LLC is listed as the broker, and October 29, 2026, is the approximate sale date.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 10/29/2026 - 01:17 PM EDT Accepted by SEC EDGAR 10/29/2026 - 01:16 PM EDT Learn about SEC filing dates

Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0001267342
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	COLUMBIA BANKING SYSTEM, INC.
SEC File Number	000-20288
Address of Issuer	1301 A STREET TACOMA WASHINGTON 98402
Phone	2533051900
Name of Person for Whose Account the Securities are To Be Sold	GARDNER STEVEN R
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Director

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Common	Fidelity Brokerage Services LLC 900 Salem Street Smithfield RI 02917	10522	328616.53	282902268	10/29/2026	NASDAQ

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Common	08/01/2011	Open Market Purchase	Issuer			180	08/01/2011	Cash
Common	08/04/2011	Open Market Purchase	Issuer			1650	08/04/2011	Cash
Common	10/03/2024	Open Market Purchase	Issuer			8692	10/03/2024	Cash

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Nothing to Report

144: Remarks and Signature

Remarks
Date of Notice	10/29/2026
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	/s/Wade Moss, as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for Steven R. Gardner
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)