Company: OSBC
Filing Date: 2025-05-08
Form Type: 424B3
Source: 0001104659-25-046065
Chunk: 376

Company: OLD SECOND BANCORP INC
Filing Date: 2025-05-08
Form: 424B3
Chunk 376
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 the application thereof, becomes or is declared by a court of competent jurisdiction to be illegal, void or unenforceable, the remainder of this Agreement will continue in full force and effect and the application of such provision to other persons or circumstances will be interpreted so as reasonably to effect the intent of the parties. The

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parties further agree to replace such void or unenforceable provision of this Agreement with a valid and enforceable provision that will achieve, to the extent possible, the purposes of such void or unenforceable provision.

19. Headings . The headings in this Agreement are inserted for convenience and identification only and are in no way intended to describe, interpret, define or limit the scope, extent or intent of this Agreement or any provision hereof.

20. Counterparts . This Agreement may be executed in counterparts, each of which shall be deemed to constitute an original, but all of which together shall constitute one and the same instrument. This Agreement and any other agreement or instrument entered into in connection with this Agreement, as well as any amendments, modifications, supplements, or waivers hereto or thereto or hereunder or thereunder, if signed and delivered by means of a facsimile machine or by email delivery of a “.pdf” format data file, shall be treated for all purposes as an original agreement or instrument and shall be considered to have the same binding legal force and effect as if it were the original signed version thereof delivered in person.

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### IN WITNESS WHEREOF
, the parties have executed this Voting Agreement as of the day and year first above written.

#### OLD SECOND BANCORP, INC.
By:

Name:

Title:

#### BANCORP FINANCIAL, INC.
By:

Name:

Title:

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### STOCKHOLDER
By:

Name:

Title:

Address:

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Exhibit A

| Stockholder | ​ | ​ | Name(s) in Which Shares areRegistered | ​ | ​ | Number ofOwned Shares* | ​ |
| ​           | ​ | ​ | ​                                     | ​ | ​ | ​                      | ​ |
| ​           | ​ |