Old Second Bancorp (OSBC) director logs RSU grant and tax-withholding share disposition

Rhea-AI Filing Summary

OLD SECOND BANCORP INC director John Williams Jr. reported equity compensation and related tax withholding transactions. On February 17, 2026, he acquired 3,121 Restricted Stock Units as a grant under the Long Term Incentive Plan, which carries three-year cliff vesting. On February 21, 2026, 3,077 RSUs were disposed of through a tax-withholding disposition at $20.57 per share to cover tax liabilities. Following these transactions, he directly held 10,595 RSUs and 36,830 shares of Old Second Bancorp common stock. The common stock total includes 6,157 shares held in his name, 20,548 shares held with a brokerage, and 10,125 shares held in a trust.

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

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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^*

Williams John JR

(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								36,830(3)	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:

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. Included in this total are 6,157 shares held in Mr. Williams' name outright; 20,548 shares held with a brokerage and 10,125 shares held in Trust.

	/s/ Shirley Cantrell, Attorney-in-Fact	02/24/2026
	** 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.
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FAQ

What insider transactions did OSBC director John Williams Jr. report?

John Williams Jr. reported a grant of 3,121 Restricted Stock Units and a tax-withholding disposition of 3,077 RSUs. These transactions reflect equity compensation under Old Second Bancorp’s Long Term Incentive Plan and related share withholding to satisfy tax obligations.

How many Restricted Stock Units did OSBC grant to John Williams Jr.?

Old Second Bancorp granted John Williams Jr. 3,121 Restricted Stock Units on February 17, 2026. The award was made under the company’s Long Term Incentive Plan and is subject to three-year cliff vesting before the units convert into common shares.

What does the RSU tax-withholding transaction mean for OSBC’s John Williams Jr.?

The 3,077 RSUs disposed at $20.57 per share represent shares withheld to cover tax liabilities. This tax-withholding disposition is not an open-market sale but an automatic mechanism tied to the vesting or settlement of John Williams Jr.’s equity compensation.

How many OSBC common shares does John Williams Jr. hold after these transactions?

After the reported transactions, John Williams Jr. holds 36,830 Old Second Bancorp common shares directly. This total comprises 6,157 shares in his name, 20,548 shares with a brokerage, and 10,125 shares held in a trust associated with him.

What is the vesting schedule for John Williams Jr.’s OSBC Restricted Stock Units?

The Restricted Stock Units granted to John Williams Jr. under Old Second Bancorp’s Long Term Incentive Plan have three-year cliff vesting. This means the full award vests only after three years, at which time vested units convert into common shares.

Are John Williams Jr.’s OSBC transactions open-market buys or sells?

The filing shows no open-market buys or sells. It reports a grant of 3,121 RSUs and a 3,077-share tax-withholding disposition at $20.57 per share, which is used to satisfy tax obligations related to vested or settled equity awards.