Old Second Bancorp (OSBC) insider reports 13,150-share sale

Rhea-AI Filing Summary

Old Second Bancorp, Inc. (OSBC) director Mr. Ladowicz reported recent changes in his ownership of the company’s common stock. On 11/26/2025, he sold 13,150 shares of Old Second Bancorp common stock from an IRA at a price of $19.0107 per share, reported as an indirect holding.

The filing also shows that 10,551 restricted stock units were disposed of at $0 on 09/14/2025, tied to units that vested automatically upon his retirement on that date. After these transactions, he beneficially owns 162,154 shares indirectly through IRA accounts and 36,121 shares directly, including shares from the vested restricted stock units.

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

OMB APPROVAL

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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^*

Ladowicz John

(Last) (First) (Middle)

8950 WILDLIFE LOOP

(Street)

SARASOTA FL 34238

(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)
11/26/2025

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
Old Second Bancorp, Inc. Common Stock	11/26/2025		S		13,150	D	$19.0107	162,154(1)	I	IRA
Restricted Stock Units	09/14/2025		J	V	10,551	D	$0	0	D
Old Second Bancorp, Inc. Common Stock								36,121(2)	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. Included in this total are 153,862 shares in a ROTH IRA and 8,292 shares in a traditional IRA.

2. Included in this total are 10,551 shares of restricted stock units that vested automatically upon Mr. Ladowicz' retirement on September 14, 2025.

	/s/ Shirley Cantrell, Attorney-in-Fact	11/26/2025
	** 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.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What did the OSBC director report on this Form 4?

The director reported a sale of 13,150 shares of Old Second Bancorp, Inc. common stock on 11/26/2025 and the vesting and disposition of 10,551 restricted stock units on 09/14/2025.

At what price were the OSBC shares sold in the reported transaction?

The 13,150 shares of Old Second Bancorp, Inc. common stock were sold at a price of $19.0107 per share.

How many OSBC shares does the reporting person own after these transactions?

After the reported transactions, the reporting person beneficially owns 162,154 shares indirectly through IRA accounts and 36,121 shares directly.

What happened to the 10,551 OSBC restricted stock units mentioned in the Form 4?

The 10,551 restricted stock units vested automatically upon Mr. Ladowicz' retirement on September 14, 2025, and are included in the reported 36,121 directly held shares.

What is the relationship of the reporting person to Old Second Bancorp, Inc. (OSBC)?

The reporting person is a Director of Old Second Bancorp, Inc.

How are the OSBC shares held by the reporting person classified in the Form 4?

The Form 4 shows 162,154 shares held indirectly in IRA accounts and 36,121 shares held directly.