Old Second Bancorp (OSBC) director adds to share stake

Rhea-AI Filing Summary

Old Second Bancorp director Billy J. Lyons Jr. reported acquiring 23 shares of Old Second Bancorp, Inc. common stock on 02/09/2026 at a price of $21.21 per share. After this transaction, he directly owns 16,996 common shares and holds 10,551 restricted stock units, all reported as direct ownership.

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

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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^*

Lyons Billy J Jr.

(Last) (First) (Middle)

37 SOUTH RIVER STREET

(Street)

AURORA IL 60507

(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)
02/09/2026

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	02/09/2026		A		23	A	$21.21	16,996	D
Restricted Stock Units								10,551	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:

	/s/ Shirley Cantrell, Attorney-in-Fact	02/10/2026
	** 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

Who is the insider in the OSBC Form 4 filing?

The insider is Billy J. Lyons Jr., a director of Old Second Bancorp, Inc. The filing reports his direct holdings of common stock and restricted stock units in the company as of the reported transaction date.

What transaction did Billy J. Lyons Jr. report for OSBC on February 9, 2026?

He reported acquiring 23 shares of Old Second Bancorp common stock on February 9, 2026 at a price of $21.21 per share. This acquisition increased his directly held common stock position in the company.

How many Old Second Bancorp shares does Billy J. Lyons Jr. own after this Form 4?

Following the reported transaction, he directly owns 16,996 shares of Old Second Bancorp common stock. The Form 4 also shows he holds 10,551 restricted stock units, which represent additional equity-based compensation linked to the company’s stock.

What price was paid per share in the latest OSBC insider stock acquisition?

The reported purchase price was $21.21 per share for Old Second Bancorp common stock. This price applies specifically to the 23 shares acquired by director Billy J. Lyons Jr. on February 9, 2026, as disclosed in the Form 4.

What restricted stock unit holdings does the OSBC director report in this Form 4?

The filing shows that Billy J. Lyons Jr. holds 10,551 restricted stock units of Old Second Bancorp. These units are reported as directly owned and represent rights to receive company shares, typically subject to vesting or service conditions.

Is the OSBC Form 4 transaction reported as direct or indirect ownership?

Both the acquired common shares and the restricted stock units are reported under direct ownership (D). The Form 4 does not list any indirect ownership entities or footnote-based attribution to separate trusts, partnerships, or family investment vehicles.