Old Second Bancorp (OSBC) EVP adds 401-K shares and updates holdings

Rhea-AI Filing Summary

OLD SECOND BANCORP INC executive Richard A. Gartelmann, Jr., an EVP, reported a routine update to his equity holdings. During the first quarter, 43 shares of Old Second Bancorp common stock were allocated to his 401-K under the company’s Employee Salary and Savings Plan. After this allocation, he indirectly holds 12,606 shares in the 401-K and directly holds 29,551 shares of common stock, along with 21,294 restricted stock units. The filing reflects ongoing compensation and retirement plan activity rather than open-market trading.

Insider Trade Summary

3 transactions reported

Mixed 3 txns

Insider Gartelmann Richard A JR

Role EVP

Type	Security	Shares	Price	Value
Other	Old Second Bancorp, Inc. Common Stock	43	$0.00	--
holding	Old Second Bancorp, Inc. Common Stock	--	--	--
holding	Restricted Stock Units	--	--	--

Holdings After Transaction: Old Second Bancorp, Inc. Common Stock — 12,606 shares (Indirect, By 401-K); Old Second Bancorp, Inc. Common Stock — 29,551 shares (Direct); Restricted Stock Units — 21,294 shares (Direct)

Footnotes (1)

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Key Figures

401-K allocation: 43 shares Indirect holdings after allocation: 12,606 shares Direct common stock holdings: 29,551 shares +1 more

4 metrics

401-K allocation 43 shares Allocated during first quarter under Employee Salary and Savings Plan

Indirect holdings after allocation 12,606 shares Old Second Bancorp common stock held via 401-K as of March 31, 2026

Direct common stock holdings 29,551 shares Directly held Old Second Bancorp common stock as of March 31, 2026

Restricted stock units 21,294 units Restricted Stock Units held as of March 31, 2026

Key Terms

Employee Salary and Savings Plan, 401-K, Restricted Stock Units, indirect ownership

4 terms

Employee Salary and Savings Plan financial

"shares were allocated during the first quarter pursuant to the Old Second Bancorp, Inc. Employee Salary and Savings Plan"

401-K financial

"43 shares were allocated during the first quarter pursuant to the Old Second Bancorp, Inc. Employee Salary and Savings Plan. Information herein was provided by the Plan Trustee"

Restricted Stock Units financial

"security_title": "Restricted Stock Units""

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

indirect ownership financial

"total_shares_following_transaction": "12606.0000", "direct_or_indirect": "I", "nature_of_ownership": "By 401-K""

Form 4 Insider Transactions: What Each Field Means →

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
Estimated average burden
hours per response:			0.5

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^*

Gartelmann Richard A JR

(Last) (First) (Middle)

37 S. RIVER ST.

(Street)

AURORA ILLINOIS 60506

(City) (State) (Zip)

UNITED STATES

(Country)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
03/31/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

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	03/31/2026		J	V	43	A	$0	12,606(1)	I	By 401-K
Old Second Bancorp, Inc. Common Stock								29,551	D
Restricted Stock Units								21,294	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, 43 shares were allocated during the first quarter pursuant to the Old Second Bancorp, Inc. Employee Salary and Savings Plan. Information herein was provided by the Plan Trustee as of 3-31-26.

	/s/ Shirley Cantrell, Attorney-in-Fact	04/02/2026
	** 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.
* Form 4: SEC 1474 (03-26)

FAQ

What insider activity did OSBC EVP Richard Gartelmann report in this Form 4?

He reported a routine update to his holdings, with 43 Old Second Bancorp shares allocated to his 401-K under the Employee Salary and Savings Plan, plus updated totals for directly held shares and restricted stock units.

How many OSBC shares were added to Richard Gartelmann’s 401-K account?

The Form 4 shows that 43 shares of Old Second Bancorp common stock were allocated to his 401-K during the first quarter under the company’s Employee Salary and Savings Plan, based on information from the plan trustee as of March 31, 2026.

What are Richard Gartelmann’s indirect OSBC holdings after this transaction?

Following the first-quarter allocation, Richard Gartelmann indirectly holds 12,606 shares of Old Second Bancorp common stock through his 401-K plan, according to information provided by the Employee Salary and Savings Plan trustee as of March 31, 2026.

How many OSBC shares does Richard Gartelmann hold directly after the Form 4 update?

The Form 4 indicates that, in addition to his 401-K holdings, Richard Gartelmann directly holds 29,551 shares of Old Second Bancorp common stock as of March 31, 2026, reflecting his personal position outside the retirement plan.

How many restricted stock units does OSBC EVP Richard Gartelmann hold?

The filing reports that Richard Gartelmann holds 21,294 restricted stock units as of March 31, 2026. These units represent a form of equity-based compensation that typically converts into common shares upon meeting vesting or service conditions.

Was this OSBC insider Form 4 a market purchase or sale of shares?

No open-market purchase or sale is reported. The only quantified change is an allocation of 43 shares to Richard Gartelmann’s 401-K under the Employee Salary and Savings Plan, categorized as an “other” type of transaction, not a standard buy or sell.