OLD SECOND BANCORP INC — Director's Dealing 2025

Oct 1, 2025

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: OLD SECOND BANCORP INC (OSBC)
CIK: 0000357173
Period of Report: 2025-09-30

Reporting Person: Gartelmann Richard A JR (N/A)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2025-09-30	Old Second Bancorp, Inc. Common Stock	J	44	—	Acquired	12516	Indirect

Holdings (Non-Derivative)

Security	Shares	Ownership
Old Second Bancorp, Inc. Common Stock	26874	Direct
Restricted Stock Units	20552	Direct

Footnotes

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.