Columbia Banking (NASDAQ: COLB) EVP reports 211-share tax withholding

Rhea-AI Filing Summary

Columbia Banking System executive Lakely Brock reported a routine tax-related share disposition. On March 13, shares of Common Stock were withheld by the issuer to satisfy tax obligations tied to an equity award vesting, totaling 211 shares at $26.23 per share. After this withholding, Brock directly holds 11,104 shares.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider Lakely Brock

Role EVP, Chief Accounting Officer

Type	Security	Shares	Price	Value
Tax Withholding	Common Stock	211	$26.23	$6K

Holdings After Transaction: Common Stock — 11,104 shares (Direct)

Footnotes (1)

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Form 4 Insider Transactions: What Each Field Means →

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Lakely Brock

(Last) (First) (Middle)

C/O COLUMBIA BANKING SYSTEM, INC.

1301 A STREET

(Street)

TACOMA WASHINGTON 98402

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
COLUMBIA BANKING SYSTEM, INC. [ COLB ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	EVP, Chief Accounting Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
03/13/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)
03/17/2026

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	03/13/2026		F(1)		211	D	$26.23	11,104	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. This Form 4/A amends the Form 4 filed on March 17, 2026 solely to correct the transaction code for the reported disposition from S to F. The transaction represents shares withheld by the issuer to satisfy tax obligations in connection with equity award vesting.

Remarks:

	/s/ Andrea M. Newburn, Attorney-in-fact	03/20/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

FAQ

What insider transaction did COLB executive Lakely Brock report on this Form 4/A?

Lakely Brock reported a tax-related share disposition. The issuer withheld 211 shares of Common Stock at $26.23 per share to satisfy tax obligations arising from equity award vesting, leaving Brock with 11,104 directly held shares afterward.

Is the Lakely Brock Form 4/A transaction for COLB an open-market sale?

The transaction is not an open-market sale. It is coded F, meaning shares were withheld by the issuer to cover tax obligations from equity award vesting, rather than being sold by Brock on the open market.

How many Columbia Banking System shares were withheld for Lakely Brock’s taxes?

A total of 211 shares of Columbia Banking System Common Stock were withheld. The shares were valued at $26.23 each for this tax-withholding event connected to the vesting of an equity award granted to Brock.

How many COLB shares does Lakely Brock hold after this Form 4/A transaction?

After the tax-withholding disposition, Lakely Brock directly holds 11,104 shares of Columbia Banking System Common Stock. This figure reflects Brock’s direct ownership immediately following the 211-share withholding related to equity award vesting.

What does the amendment in Lakely Brock’s Form 4/A for COLB correct?

The amendment corrects the transaction code from S to F. It clarifies that the reported disposition reflects shares withheld by the issuer to satisfy tax obligations from equity award vesting, not an open-market sale of Columbia Banking System stock.

What role does Lakely Brock hold at Columbia Banking System (COLB)?

Lakely Brock serves as Executive Vice President and Chief Accounting Officer. This officer role is disclosed in the Form 4/A, which reports the tax-related share withholding tied to Brock’s equity compensation vesting in Columbia Banking System stock.