Richard A. Gartelmann Jr. - 17 Feb 2026 Form 4 Insider Report for OLD SECOND BANCORP INC (OSBC)

Role
EVP
Signature
/s/ Shirley Cantrell, Attorney-in-Fact
Issuer symbol
OSBC
Transactions as of
17 Feb 2026
Net transactions value
-$18,390
Form type
4
Filing time
24 Feb 2026, 18:50:14 UTC
Previous filing
05 Feb 2026
Next filing
04 Mar 2026

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Gartelmann Richard A JR EVP 37 S. RIVER ST., AURORA /s/ Shirley Cantrell, Attorney-in-Fact 24 Feb 2026 0001840027

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction OSBC Restricted Stock Units Award $0 +5,912 +29% $0.000000 26,464 17 Feb 2026 Direct F1
transaction OSBC Restricted Stock Units Tax liability $18,390 -894 -3.6% $20.57 23,879 21 Feb 2026 Direct F2
holding OSBC Old Second Bancorp, Inc. Common Stock 1,691 17 Feb 2026 Direct F3
holding OSBC Old Second Bancorp, Inc. Common Stock 24,874 17 Feb 2026 Direct
holding OSBC Old Second Bancorp, Inc. Common Stock 12,563 17 Feb 2026 By 401-K
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 Each restricted stock unit represents a contingent right to receive one share of common stock. The reporting person was granted 5,912 restricted stock units on the date of the grant, 2,956 of which are time-based restricted stock units that vest on the third anniversary of the grant date, and 2,956 of which are performance-based restricted stock units that may vest and convert to shares within a range from 0% to 175% of the underlying performance-based restricted stock units originally awarded, depending on our compensation committee approved performance metrics. Vested shares, if any, will be delivered to the reporting person in 3 to 5 business days from the date of vesting.
F2 Represents shares withheld by the issuer to satisfy applicable tax withholding obligations in connection with the vesting of 2,585 previously reported time-based restricted stock units, the remaining shares of which were issued and added to the reporting person's common stock holdings.
F3 These shares are held in Mr. Gartelmann's name outright.