[Form 4] Old Second Bancorp Inc Insider Trading Activity

Rhea-AI Filing Summary

On 08/04/2025, Old Second Bancorp (OSBC) director Billy J. Lyons Jr. reported an open-market purchase of 25 common shares at $16.61 (transaction code “P”). After the trade, his direct holdings increased to 16,946 shares, split between 8,353 shares held outright and 8,593 shares in a brokerage account; he also retains 10,551 restricted stock units. No derivative activity was disclosed and the filing was signed by attorney-in-fact Shirley Cantrell on 08/05/2025, complying with Section 16 timing rules. The transaction adds less than 0.2 % to Lyons’ stake and is not indicated as part of a Rule 10b5-1 plan. While insider buying can be viewed as a positive signal, the small dollar value of this trade limits its materiality for investors.

Insights

Financial Analyst

Tiny insider buy; informational value limited—overall neutral impact.

The purchase of 25 shares (~$415) is immaterial relative to both the director’s existing stake (16,946 shares) and OSBC’s public float. It does not meaningfully alter insider ownership or signal a strong conviction about valuation. Filing timeliness and transparency are routine, with no derivative positions added or sold. Given the negligible size and absence of related trades, the event is best interpreted as housekeeping rather than a strategic move. Investors should wait for larger insider transactions or fundamental catalysts before adjusting valuation models.

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

OMB Number:			3235-0287
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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)
08/04/2025

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	08/04/2025		P		25	A	$16.61	16,946(1)	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:

1. Included in this total are 8,353 shares held outright in Mr. Lyon's name and 8,593 shares held in Mr. Lyon's name in a brokerage account.

	/s/ Shirley Cantrell, Attorney-in-Fact	08/05/2025
	** 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

How many Old Second Bancorp (OSBC) shares did director Billy J. Lyons Jr. purchase?

He bought 25 common shares on 08/04/2025 at $16.61 each.

What is Lyons’s total direct ownership after the transaction?

His direct holdings increased to 16,946 OSBC shares.

How many restricted stock units does Lyons hold?

He holds 10,551 restricted stock units.

Was the transaction a purchase or a sale?

It was coded “P,” indicating an open-market purchase.

When was the Form 4 filed?

The filing was submitted on 08/05/2025.

Is this trade part of a Rule 10b5-1 trading plan?

The filing does not indicate that the trade was executed under a Rule 10b5-1 plan.