Company: MCHB
Filing Date: 2025-07-16
Form Type: 424B3
Source: 0001140361-25-026051
Chunk: 523

Company: Mechanics Bancorp
Filing Date: 2025-07-16
Form: 424B3
Chunk 523
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 for all purposes, and such execution and transmission shall be considered valid, binding and effective for all purposes.

This Written Consent shall be effective as of the execution and delivery of this Written Consent in accordance with the terms of the Merger Agreement and shall be filed with the corporate records of the Corporation. To the extent permissible under applicable law, each Consenting Holder hereby waives any and all notice requirements applicable to, or triggered by, the Merger Agreement and the Transactions under applicable law or that are contained in (a) the Restated Articles of Incorporation of the Corporation, (b) the Bylaws of the Corporation or (c) any agreement between the Corporation and such Consenting Holder or under applicable law.

<div align='center'>[ Signature page follows ]

A-72</div>

TABLE OF CONTENTS

IN WITNESS WHEREOF, the undersigned has executed this Written Consent on the date set forth below.

| [CONSENTING HOLDER] |     |        |
| By:                 |     |        |
|                     |     | Name:  |
|                     |     | Title: |
| Date:               |     |        |

A-73

TABLE OF CONTENTS

Annex A Consenting Holder Shares

| Shares of Common Stock |
| [•]                    |

A-74

#### TABLE OF CONTENTS

#### Annex B

#### Merger Agreement
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#### TABLE OF CONTENTS

#### Exhibit A-2

#### Form of Support Agreement
EXECUTION VERSION

### VOTING AND SUPPORT AGREEMENT
This VOTING AND SUPPORT AGREEMENT, dated as of March 28, 2025 (this “ Agreement ”), is made by and between HomeStreet, Inc., a Washington corporation (“ Parent ”) and [•] (the “ Shareholder ”) (together, the “ Parties ” and each a “ Party ”).

### W I T N E S E T H
WHEREAS, on March 28, 2025, Parent, HomeStreet Bank, a Washington state-chartered commercial bank and a direct and wholly owned subsidiary of Parent (“ Parent Bank ”), and Mechanics Bank (“ Company ”) entered into an Agreement and Plan of Merger (the “ Merger Agreement ”), pursuant to which, among other things, Parent Bank will merge with and into Company (the “ Merger ”), so that Company is the surviving entity in the Merger, upon the terms and subject to the conditions set forth in the