Company: OSBC
Filing Date: 2025-04-23
Form Type: S-4
Source: 0001104659-25-037832
Chunk: 364

Company: OLD SECOND BANCORP INC
Filing Date: 2025-04-23
Form: S-4
Chunk 364
---
 or instrument shall raise the use of a facsimile machine or e-mail delivery of a “.pdf” format data file to deliver a signature to this Agreement or any amendment hereto or the fact that any signature or agreement or instrument was transmitted or communicated through the use of a facsimile machine or e-mail delivery of a “.pdf” format data file as a defense to the formation of a contract and each Party hereto forever waives any such defense.

<div align='center'>[Signatures appear on next page]

A-66</div>

TABLE OF CONTENTS

### IN WITNESS WHEREOF
, each of the Parties has caused this Agreement to be executed on its behalf by its duly authorized officers as of the day and year first above written.

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

/s/ James L. Eccher

Name: James L. Eccher

Title: Chairman, President and CEO

#### BANCORP FINANCIAL, INC.
By:

/s/ Darin Campbell

Name: Darin Campbell

Title: Chairman, President and CEO

<div align='center'>A-67</div>

TABLE OF CONTENTS

### EXHIBIT A

### FORM OF COMPANY VOTING AGREEMENT

### THIS VOTING AGREEMENT
(this “ Agreement ”), dated as of [•], 2025 (“ Agreement Date ”), is entered into by and among (i) Bancorp Financial, Inc., a Delaware corporation (the “ Company ”), (ii) Old Second Bancorp, Inc., a Delaware corporation (“ Buyer ”), and (iii) each person or entity executing this Agreement or a counterpart to this Agreement as a stockholder of the Company and listed on Exhibit A hereto (collectively, the “ Stockholders ” and each, a “ Stockholder ”).

### WITNESSETH
<div align='center'>:</div>

### WHEREAS
, pursuant to the terms of the Agreement and Plan of Merger (as the same may be amended or supplemented, the “ Merger Agreement ”), dated as of the date hereof and to be executed by the Company and Buyer concurrently with the execution of this Agreement by the parties hereto, among other things and subject to the terms and conditions set forth therein, the Company will be merged with and into Buyer (“ Merger ”), with Buyer surviving the Merger as the surviving corporation;

### WHEREAS
, as an inducement for Buyer to enter into the Merger Agreement,