Bradley S. Adams - 31 Dec 2025 Form 4 Insider Report for OLD SECOND BANCORP INC (OSBC)

Role: CFO & COO
Signature: /s/ Shirley Cantrell, Attorney-in-Fact
Issuer symbol: OSBC
Transactions as of: 31 Dec 2025
Net transactions value: $0
Form type: 4
Filing time: 05 Jan 2026, 18:16:38 UTC
Previous filing: 01 Oct 2025
Next filing: 24 Feb 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
ADAMS BRADLEY S.	CFO & COO	37 S. RIVER ST., AURORA	/s/ Shirley Cantrell, Attorney-in-Fact	05 Jan 2026	0001598917

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	OSBC	Old Second Bancorp, Inc. Common Stock	Award	$0	+39	+0.39%	$0.000000	10,124	31 Dec 2025	By 401-k Plan	F1
holding	OSBC	Old Second Bancorp, Inc. Common Stock						143,308	31 Dec 2025	Direct	F2
holding	OSBC	Restricted Stock Units						77,444	31 Dec 2025	Direct

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	Of this total, 39 shares were allocated during the fourth quarter pursuant to the Old Second Bancorp, Inc. Salary & Savings Plan. Information herein was provided by the Plan Trustee as of 12-31-25.
F2	Included in this total are 75,300 shares held jointly with spouse in a brokerage account and 68,008 shares held jointly outright.