COLUMBIA BANKING SYSTEM (COLB) counsel exercises RSUs, sells shares

Rhea-AI Filing Summary

COLUMBIA BANKING SYSTEM EVP and General Counsel Kumi Yamamoto Baruffi exercised restricted stock units and sold a portion of the resulting shares. On March 13, 2026, 2,381 Restricted Stock Units were converted into 2,381 shares of common stock at an effective price of $0.00 per share. On the same date, 937 common shares were sold at $26.23 per share, leaving 53,715 common shares held directly after the sale. A prior grant of 7,142 Restricted Stock Units made on February 25, 2025 vests in three annual installments beginning March 13, 2026.

Insights

Equity compensation and insider trading analyst

Routine RSU vesting with a modest same-day share sale.

The filing shows EVP and General Counsel Kumi Yamamoto Baruffi converting 2,381 Restricted Stock Units into common stock, then selling 937 shares at $26.23. This is a classic exercise-and-partial-sell pattern tied to equity compensation.

Following the transactions, she directly holds 53,715 common shares, indicating most equity exposure was retained. The footnote notes a grant of 7,142 RSUs on February 25, 2025 that vests over three years starting March 13, 2026, underscoring an ongoing, structured compensation program.

Insider Trade Summary

Exercise and sale activity reported; no spread calculated

Exercise and Sale 3 txns

Insider BARUFFI KUMI YAMAMOTO

Role EVP General Counsel, Corp Sec

Sold 937 shs ($25K)

Approx. gross sale proceeds $25K

Approx. exercise cost $0.00

Type	Security	Shares	Price	Value
Exercise	Restricted Stock Unit	2,381	$0.00	$0.00
Exercise	Common Stock	2,381	$26.23	$62K
Sale	Common Stock	937	$26.23	$25K

Holdings After Transaction: Restricted Stock Unit — 13,083 shares (Direct); Common Stock — 53,715 shares (Direct)

Footnotes (1)

1. F1. Restricted Stock Units convert into common stock on a one-for-one basis. On February 25, 2025, the reporting person was granted 7,142 Restricted Stock Units, which vest in three annual installments beginning on March 13, 2026.

FAQ

What insider transactions did COLB executive Kumi Yamamoto Baruffi report?

She reported exercising 2,381 Restricted Stock Units into 2,381 common shares, then selling 937 common shares at $26.23 per share. After these transactions, she directly held 53,715 shares of Columbia Banking System common stock.

Did the COLB insider filing show a stock sale or purchase?

The Form 4 shows both an acquisition and a sale. RSUs were converted into 2,381 common shares, and 937 of those shares were sold in an open-market transaction at $26.23 per share on March 13, 2026.

How many COLUMBIA BANKING SYSTEM (COLB) shares does the executive hold after the transactions?

After the reported transactions, EVP and General Counsel Kumi Yamamoto Baruffi directly holds 53,715 shares of Columbia Banking System common stock. This figure reflects the net position after exercising RSUs and selling 937 shares.

What does the RSU grant in the COLB Form 4 disclosure involve?

The footnote states she was granted 7,142 Restricted Stock Units on February 25, 2025. These RSUs vest in three annual installments beginning March 13, 2026, and each unit converts into one share of Columbia Banking System common stock upon vesting.

At what price were the COLUMBIA BANKING SYSTEM (COLB) shares sold in this filing?

The sale transaction in the Form 4 shows 937 common shares sold at $26.23 per share. This sale followed the conversion of 2,381 Restricted Stock Units into an equal number of common shares on the same date.

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Form 4 Insider Transactions: What Each Field Means →

Accepted by SEC EDGAR 03/17/2026 - 08:26 PM Learn about SEC filing dates

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^*

BARUFFI KUMI YAMAMOTO

(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 General Counsel, Corp Sec

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

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	03/13/2026		M		2,381	A	$26.23	54,652	D
Common Stock	03/13/2026		S		937	D	$26.23	53,715	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
Restricted Stock Unit	(1)	03/13/2026		M			2,381	(1)	(1)	Common Stock	2,381	$0	13,083	D

Explanation of Responses:

1. Restricted Stock Units convert into common stock on a one-for-one basis. On February 25, 2025, the reporting person was granted 7,142 Restricted Stock Units, which vest in three annual installments beginning on March 13, 2026.

Remarks:

	/s/ Andrea M. Newburn, Attorney-in-fact	03/17/2026
	** 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.