Old Second Bancorp (OSBC) director awarded RSUs, with shares withheld

Rhea-AI Filing Summary

OLD SECOND BANCORP INC director Dennis L. Klaeser received a grant of 3,121 Restricted Stock Units under the company’s Long Term Incentive Plan, which have three-year cliff vesting. On vesting, 3,077 shares were disposed of at $20.57 per share to cover tax obligations, with the remaining shares added to his common stock holdings.

Insider Trade Summary

4 transactions reported

Mixed 4 txns

Insider KLAESER DENNIS L

Role Director

Type	Security	Shares	Price	Value
Tax Withholding	Restricted Stock Units	3,077	$20.57	$63K
Grant/Award	Restricted Stock Units	3,121	$0.00	--
holding	Old Second Bancorp, Inc. Common Stock	--	--	--
holding	Old Second Bancorp, Inc. Common Stock	--	--	--

Holdings After Transaction: Restricted Stock Units — 10,595 shares (Direct); Old Second Bancorp, Inc. Common Stock — 7,657 shares (Direct); Old Second Bancorp, Inc. Common Stock — 42,000 shares (Indirect, Trust)

Footnotes (1)

1. These shares represent restricted stock units granted pursuant to the Old Second Bancorp, Inc. Long Term Incentive Plan. These shares have a three-year cliff vesting. Represents shares vested upon the third anniversary of the date of grant previously reported and are now issued and added to the reporting person's common stock holdings outright. Represents shares held in Mr. Klaeser's name outright.

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^*

KLAESER DENNIS L

(Last) (First) (Middle)

37 S. RIVER ST.

(Street)

AURORA IL 60506

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
OLD SECOND BANCORP INC [ OSBC ]

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

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
02/17/2026

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
Restricted Stock Units	02/17/2026		A		3,121(1)	A	$0	13,672	D
Restricted Stock Units	02/21/2026		F		3,077(2)	D	$20.57	10,595	D
Old Second Bancorp, Inc. Common Stock								7,657(3)	D
Old Second Bancorp, Inc. Common Stock								42,000	I	Trust

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. These shares represent restricted stock units granted pursuant to the Old Second Bancorp, Inc. Long Term Incentive Plan. These shares have a three-year cliff vesting.

2. Represents shares vested upon the third anniversary of the date of grant previously reported and are now issued and added to the reporting person's common stock holdings outright.

3. Represents shares held in Mr. Klaeser's name outright.

	/s/ Shirley Cantrell, Attorney-in-Fact	02/25/2026
	** 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 transactions did OSBC director Dennis Klaeser report?

Dennis Klaeser reported a grant of 3,121 Restricted Stock Units and a disposition of 3,077 shares at $20.57 per share for tax withholding. These movements relate to equity compensation rather than open-market buying or selling of OLD SECOND BANCORP INC stock.

Was the OSBC insider transaction a stock sale in the open market?

No, the 3,077 shares at $20.57 were a tax-withholding disposition tied to vested Restricted Stock Units. This transaction settled tax obligations on equity compensation, not a discretionary open-market sale by Dennis Klaeser of OLD SECOND BANCORP INC shares.

How many Restricted Stock Units did the OSBC director receive?

Dennis Klaeser received 3,121 Restricted Stock Units at a stated price of $0.00 per unit. The award was granted under OLD SECOND BANCORP INC’s Long Term Incentive Plan and is subject to a three-year cliff vesting schedule before shares are issued outright.

What is the vesting schedule for Dennis Klaeser’s OSBC RSU grant?

The Restricted Stock Units granted to Dennis Klaeser vest on a three-year cliff schedule. After three years from the grant date, the units vest and are issued as common shares, which are then added to his OLD SECOND BANCORP INC common stock holdings outright.

How many OSBC shares does Dennis Klaeser hold directly after these transactions?

Following the reported transactions, Dennis Klaeser directly holds 10,595 Restricted Stock Units and 7,657 shares of OLD SECOND BANCORP INC common stock. The filing also lists 42,000 common shares held indirectly through a trust as part of his reported ownership.