Columbia Banking (NASDAQ: COLB) EVP converts 2,820 RSUs, 1,367 shares withheld

Rhea-AI Filing Summary

Columbia Banking System EVP and Chief Credit Officer Frank Namdar exercised restricted stock units into common shares. On March 13, 2026, 2,820 Restricted Stock Units converted into 2,820 shares of Common Stock, with the common stock valued at $26.23 per share in this transaction.

To cover tax obligations, 1,367 Common Stock shares were withheld, a non-market disposition that does not represent an open-market sale. After these transactions, Namdar directly held 31,923 Common Stock shares and indirectly held 4,179 shares through a 401(k) plan. The footnotes note that 8,458 Restricted Stock Units were originally granted on February 25, 2025, vesting in three annual installments beginning March 13, 2026.

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
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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^*

Namdar Frank

(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 Credit Officer

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		2,820	A	$26.23	33,290	D
Common Stock	03/13/2026		F		1,367	D	$26.23	31,923	D
Common Stock								4,179	I	by 401(k)

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			2,820	(1)	(1)	Common Stock	2,820	$0	13,640	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 8,458 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.

FAQ

What insider transaction did COLB executive Frank Namdar report?

Frank Namdar reported exercising 2,820 Restricted Stock Units into 2,820 shares of Columbia Banking System Common Stock. The event occurred on March 13, 2026, as part of his equity compensation program, and reflects a routine conversion of RSUs into shares rather than an open-market purchase.

How many Columbia Banking System shares does Frank Namdar hold after this Form 4?

After the reported transactions, Frank Namdar directly held 31,923 shares of Columbia Banking System Common Stock and indirectly held 4,179 shares through a 401(k) plan. These holdings reflect his position following the RSU conversion and related tax-withholding share disposition.

Were any COLB shares sold on the open market in this Form 4 filing?

No open-market sales were reported. The filing shows 1,367 Common Stock shares were disposed of to cover tax obligations at $26.23 per share. This F-code tax-withholding disposition is a mechanical step tied to the RSU vesting, not a discretionary market sale.

What are the terms of Frank Namdar’s Restricted Stock Unit grant at Columbia Banking System?

The footnote states that on February 25, 2025, Frank Namdar was granted 8,458 Restricted Stock Units. These units vest in three annual installments beginning on March 13, 2026, with each vested unit converting into one share of Common Stock on a one-for-one basis.

What price per share is associated with the COLB stock in this insider transaction?

The Form 4 shows a price of $26.23 per share for the Common Stock involved in the March 13, 2026 transactions. This value is used for the share conversion and tax-withholding calculations, rather than indicating an open-market trade execution price.

How many COLB shares were withheld for taxes in Frank Namdar’s transaction?

The filing reports that 1,367 Common Stock shares were withheld to satisfy tax obligations related to the RSU conversion. This tax-withholding disposition is coded as an F transaction and is part of standard equity compensation processing, not an open-market sale.