Darin Patrick Campbell - Jul 18, 2025 Form 4 Insider Report for OLD SECOND BANCORP INC (OSBC)

Role: President, Powersports Lending, Director
Signature: /s/ Shirley Cantrell, Attorney-in-Fact
Stock symbol: OSBC
Transactions as of: Jul 18, 2025
Transactions value $: $0
Form type: 4
Date filed: 7/21/2025, 05:56 PM
Previous filing: Jul 8, 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Campbell Darin Patrick	President, Powersports Lending, Director	37 S. RIVER ST., AURORA	/s/ Shirley Cantrell, Attorney-in-Fact	2025-07-21	0002074132

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	+57.6K		$0.00	57.6K	Jul 18, 2025	IRA	F1
holding	OSBC	Old Second Bancorp, Inc. Common Stock						310K	Jul 18, 2025	Direct	F2

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

Explanation of Responses:

Id	Content
F1	These shares were issuable pursuant to the merger of Bancorp Financial, Inc. with and into Old Second Bancorp, Inc., which became effective on July 1, 2025. The reporting person held 22,300 shares of Bancorp Financial, Inc., which pursuant to the merger agreement was converted into 57,565 shares of Old Second Bancorp, Inc. common stock. These shares are held in a custodial account in an IRA on behalf of the reporting person. The exchange of shares occurred on July 19, 2025.
F2	These securities are issuable pursuant to the merger of Bancorp Financial, Inc. with and into Old Second Bancorp, Inc., which became effective on July 1, 2025. The reporting person held 119,966 shares of Bancorp Financial, Inc., which pursuant to the merger agreement, will be converted into 309,680 shares of Old Second Bancorp, Inc. common stock. The exchange of shares has not yet occurred, but the right to receive the shares is fixed and irrevocable under the merger agreement. The exchange of shares occurred on July 18, 2025.

Content

These shares were issuable pursuant to the merger of Bancorp Financial, Inc. with and into Old Second Bancorp, Inc., which became effective on July 1, 2025. The reporting person held 22,300 shares of Bancorp Financial, Inc., which pursuant to the merger agreement was converted into 57,565 shares of Old Second Bancorp, Inc. common stock. These shares are held in a custodial account in an IRA on behalf of the reporting person. The exchange of shares occurred on July 19, 2025.

These securities are issuable pursuant to the merger of Bancorp Financial, Inc. with and into Old Second Bancorp, Inc., which became effective on July 1, 2025. The reporting person held 119,966 shares of Bancorp Financial, Inc., which pursuant to the merger agreement, will be converted into 309,680 shares of Old Second Bancorp, Inc. common stock. The exchange of shares has not yet occurred, but the right to receive the shares is fixed and irrevocable under the merger agreement. The exchange of shares occurred on July 18, 2025.