Richard A. Gartelmann Jr. - 30 Sep 2025 Form 4 Insider Report for OLD SECOND BANCORP INC (OSBC)

Role: EVP
Signature: /s/ Shirley Cantrell, Attorney-in-Fact
Issuer symbol: OSBC
Transactions as of: 30 Sep 2025
Net transactions value: $0
Form type: 4
Filing time: 01 Oct 2025, 16:26:39 UTC
Previous filing: 08 Jul 2025
Next filing: 05 Jan 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Gartelmann Richard A JR	EVP	37 S. RIVER ST., AURORA	/s/ Shirley Cantrell, Attorney-in-Fact	01 Oct 2025	0001840027

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	OSBC	Old Second Bancorp, Inc. Common Stock	Other	$0	+44	+0.35%	$0.000000	12,516	30 Sep 2025	By 401-K	F1
holding	OSBC	Old Second Bancorp, Inc. Common Stock						26,874	30 Sep 2025	Direct	F2
holding	OSBC	Restricted Stock Units						20,552	30 Sep 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, 44 shares were allocated during the third quarter pursuant to the Old Second Bancorp, Inc. Salary and Savings Plan. Information was provided herein by the Plan Trustee as of 9-30-25.
F2	These shares are held in the reporting person's name alone.