Columbia Banking (COLB) EVP uses company shares to cover tax bill

Rhea-AI Filing Summary

Columbia Banking System EVP and Chief Accounting Officer Lakely Brock had 396 shares of Common Stock withheld to cover tax obligations, based on a value of $29.10 per share. This tax-withholding disposition is not an open-market sale. After the transaction, Brock directly holds 10,708 shares of Columbia Banking System common stock.

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	396	$29.10	$12K

Holdings After Transaction: Common Stock — 10,708 shares (Direct)

Footnotes (1)

Key Figures

Tax-withheld shares: 396 shares Share value for withholding: $29.10 per share Shares held after transaction: 10,708 shares

3 metrics

Tax-withheld shares 396 shares Shares delivered for tax-withholding disposition on Common Stock

Share value for withholding $29.10 per share Value used for the tax-withholding disposition

Shares held after transaction 10,708 shares Direct ownership of Columbia Banking System common stock after disposition

Key Terms

tax-withholding disposition, Common Stock, Form 4, exercise price or tax liability

4 terms

tax-withholding disposition financial

"The transaction is described as a tax-withholding disposition of 396 shares."

A tax-withholding disposition is an event or transaction—such as selling or transferring securities, exercising options, or receiving compensation—that triggers a requirement to hold back part of the payment and remit it to tax authorities. It matters to investors because it reduces the cash they receive immediately and can change the timing and amount of taxable income, like a cashier taking a portion of your sale proceeds to pay taxes before you get the rest.

Common Stock financial

"The security involved in the transaction is identified as Common Stock."

Common stock represents ownership shares in a company, giving investors a stake in its success and a say in important decisions through voting rights. It is the most common type of stock traded on markets and can provide income through dividends, as well as potential for value growth. For investors, holding common stock means sharing in the company’s profits and risks.

Form 4 regulatory

"The insider activity is reported on a Form 4 insider trading report."

Form 4 is a official document that company insiders, such as executives or major shareholders, file with regulators whenever they buy or sell company shares. It provides transparency about how those with inside knowledge are trading, helping investors see if insiders are confident in the company's prospects or may be selling for personal reasons. This information can influence investor decisions by revealing insiders' perspectives on the company's value.

exercise price or tax liability financial

"Code F refers to payment of an exercise price or tax liability by delivering securities."

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)
04/15/2026

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)

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	04/15/2026		F		396	D	$29.1	10,708	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:

Remarks:

	/s/ Andrea M. Newburn, Attorney-in-fact	04/16/2026
	** 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?

Lakely Brock reported a tax-withholding disposition of 396 shares of Columbia Banking System common stock. The shares were used to satisfy tax obligations, rather than sold on the open market, and relate to compensation in stock form.

Was the COLB insider transaction a market sale of shares?

No. The filing describes a tax-withholding disposition, not an open-market sale. Shares were delivered to cover tax liabilities associated with equity compensation, so the executive did not actively sell these shares into the market.

At what price were the COLB shares valued for this tax-withholding event?

The 396 shares involved in the tax-withholding disposition were valued at $29.10 per share. This price is used solely to determine the value of shares applied toward the tax obligation, not as a reported market trade execution price.

How many COLB shares does Lakely Brock hold after this transaction?

Following the tax-withholding disposition, Lakely Brock directly holds 10,708 shares of Columbia Banking System common stock. This figure reflects the remaining direct ownership after 396 shares were delivered to satisfy tax liabilities.

What does transaction code "F" mean in the COLB Form 4 filing?

Transaction code "F" indicates payment of an exercise price or tax liability by delivering securities. In this case, it shows COLB shares were withheld to cover taxes related to equity compensation, rather than representing a discretionary market trade.