Columbia Banking (NASDAQ: COLB) EVP reports 918-share tax-withholding move

Rhea-AI Filing Summary

COLUMBIA BANKING SYSTEM, INC. executive Aaron James Deer, EVP Chief Strategy/Innovation Officer, reported a tax-related share disposition. On March 1, 2026, he transferred 918 shares of common stock at $28.45 per share as a tax-withholding disposition, classified under code F. After this transaction, he directly owned 40,925 shares of common stock.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider Deer Aaron James

Role EVP Chief Strategy/Innov Offcr

Type	Security	Shares	Price	Value
Tax Withholding	Common Stock	918	$28.45	$26K

Holdings After Transaction: Common Stock — 40,925 shares (Direct)

Footnotes (1)

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^*

Deer Aaron James

(Last) (First) (Middle)

C/O COLUMBIA BANKING SYSTEM, INC.

1301 A STREET

(Street)

TACOMA WA 98402

(City) (State) (Zip)

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 Strategy/Innov Offcr

3. Date of Earliest Transaction (Month/Day/Year)
03/01/2026

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

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

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

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	03/01/2026		F		918	D	$28.45	40,925	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	03/02/2026
	** 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.

FAQ

What insider transaction did COLB executive Aaron James Deer report?

Aaron James Deer reported a tax-withholding disposition of COLB common stock. He transferred 918 shares on March 1, 2026, in a transaction classified under code F, which covers payment of tax liability by delivering securities.

How many COLB shares did Aaron James Deer dispose of for taxes?

He disposed of 918 shares of COLUMBIA BANKING SYSTEM, INC. common stock. The transaction was a tax-withholding disposition at a reported price of $28.45 per share, used to satisfy tax obligations related to equity compensation.

What does transaction code F mean in Aaron James Deer’s COLB Form 4?

Transaction code F indicates payment of an exercise price or tax liability by delivering securities. In this COLB filing, it reflects a tax-withholding disposition, not an open-market purchase or sale, tied to equity compensation events.

How many COLB shares does Aaron James Deer own after this Form 4 transaction?

After the reported transaction, Aaron James Deer directly owned 40,925 shares of COLB common stock. This figure reflects his direct ownership immediately following the 918-share tax-withholding disposition reported on March 1, 2026.

Was Aaron James Deer’s COLB transaction a market sale or tax withholding?

The transaction was a tax-withholding disposition, not a regular market sale. It is coded F, meaning shares were delivered to cover an exercise price or tax liability associated with Columbia Banking System equity awards.