[Form 4] OLD SECOND BANCORP INC Insider Trading Activity

Rhea-AI Filing Summary

Donald Pilmer, an EVP and officer of Old Second Bancorp, reported Form 4 transactions dated 09/30/2025 showing allocations from company benefit plans and a disposition of restricted stock units. The filing lists 182 shares from the Profit Sharing Plan and 3,995 shares from the Employee Salary Savings (401-k) Plan allocated to accounts, plus 1,450 shares held in a spouse's IRA. The report also shows a disposition of 38,718 Restricted Stock Units. After the transactions, the filing lists 63,135 shares as indirectly beneficially owned, which the filer explains includes brokerage holdings, custodial shares, and remaining RSUs.

Positive

• Plan allocations increased beneficial holdings: 182 shares from the Profit Sharing Plan and 3,995 shares from the Employee Salary Savings Plan were allocated.
• Clear disclosure of holdings: Filing provides a detailed breakdown of the components making up the 63,135 indirectly beneficially owned shares.

Negative

• Significant RSU disposition: 38,718 Restricted Stock Units were reported disposed, reducing the insider's RSU position.

Insights

Securities Analyst

TL;DR: Routine plan allocations increased indirect holdings while a large block of RSUs was disposed, overall a neutral insider activity for investors.

The filing documents routine allocations from the company's profit sharing and salary savings plans totaling 4,177 shares allocated in the quarter (182 + 3,995). These are plan trustee-reported allocations and represent passive increases in beneficial ownership. The notable item is the disposition of 38,718 Restricted Stock Units, which materially reduces Mr. Pilmer's unvested/held RSU position. The filing states total indirect beneficial ownership of 63,135 shares, comprised of custodial shares, brokerage holdings, and remaining RSUs. For investors, this appears to be ordinary insider activity rather than an event-driven trade; no derivative transactions or option exercises are reported.

Corporate Governance Expert

TL;DR: Insider reported plan allocations and RSU disposal; disclosure is clear and consistent with routine compensation and account activity.

The Form 4 identifies Mr. Pilmer as an EVP and reports allocations from the Profit Sharing Plan and 401(k), which are typical compensation-related allocations and reflected as indirect ownership. The separate line showing disposition of 38,718 Restricted Stock Units merits attention for governance because it changes the composition of insider-held equity, but the filing does not indicate any related-party transfer or special transaction. Recordkeeping notes from plan trustees are included, improving transparency. Overall, disclosure meets Section 16 reporting expectations and contains specific breakdowns of holdings for clarity.

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).

1. Name and Address of Reporting Person^*

Pilmer Donald

(Last) (First) (Middle)

37 S. RIVER ST.

(Street)

AURORA IL 60506

(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)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	EVP

3. Date of Earliest Transaction (Month/Day/Year)
09/30/2025

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	09/30/2025		J	V	1	A	$0	182(1)	I	By Profit Sharing Plan
Old Second Bancorp, Inc. Common Stock	09/30/2025		J	V	14	A	$0	3,995(2)	I	By 401-K Plan
Old Second Bancorp, Inc. Common Stock								1,450(3)	I	Spouse's IRA
Old Second Bancorp, Inc. Common Stock								63,135(4)	D
Restricted Stock Units								38,718	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. Of this total, 1 share was allocated during the third quarter pursuant to the Old Second Bancorp, Inc. Profit Sharing Plan Plan. Information herein was provided by the plan trustee as of 09-30-25.

2. Of this total, 14 shares were allocated during the third quarter pursuant to the Old Second Bancorp, Inc. Employee Salary Savings Plan. Information herein was provided by the plan trustee as of 09-30-25.

3. These shares are held in spouse's IRA for which Mr. Pilmer is listed as a beneficiary.

4. Included in this total are 10 shares in Mr. Pilmer's name as custodian; 34,023 shares held in a brokerage account, 4,295 in his name alone and 26,381 shares of Restricted Stock Units.

	/s/ Shirley Cantrell, Attorney-in-Fact	10/01/2025
	** 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 transactions did Donald Pilmer report on Form 4 for OSBC?

The Form 4 reports allocations of 182 shares from the Profit Sharing Plan and 3,995 shares from the Employee Salary Savings Plan, 1,450 shares in a spouse's IRA, and a disposition of 38,718 Restricted Stock Units.

How many shares does Mr. Pilmer beneficially own according to the filing?

The filing lists 63,135 shares as indirectly beneficially owned, with an explanatory breakdown of custodial, brokerage, and RSU holdings.

Were any derivative securities (options, warrants) reported?

No derivative securities or option exercises are reported in Table II of the Form 4.

Do the Form 4 transactions appear to be part of compensation plans?

Yes. The filing states allocations were made by the plan trustee from the Profit Sharing Plan and the Employee Salary Savings (401-k) Plan.

Does the filing explain the composition of the 63,135 shares?

Yes. The explanation lists 10 custodian shares, 34,023 shares in a brokerage account, 4,295 shares in his name alone, and 26,381 shares of Restricted Stock Units (per the explanatory note).