Company: BWXT
Filing Date: 2025-03-19
Form Type: DEFA14A
Source: 0001486957-25-000017
Chunk: 0

Company: BWX Technologies, Inc.
Filing Date: 2025-03-19
Form: DEFA14A
Chunk 0
---
### UNITED STATES

### SECURITIES AND EXCHANGE COMMISSION

#### Washington, D.C. 20549

#### SCHEDULE 14A
<div align='center'>(Rule 14a-101)</div>

#### Proxy Statement Pursuant to Section 14(a) of the

#### Securities Exchange Act of 1934
<div align='center'>(Amendment No. )</div>

Filed by the Registrant ý

Filed by a Party other than the Registrant ☐

Check the appropriate box:

| ☐ |     | Preliminary Proxy Statement                                                     |
| ☐ |     | Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) |
| ☐ |     | Definitive Proxy Statement                                                      |
| ý |     | Definitive Additional Materials                                                 |
| ☐ |     | Soliciting Material Pursuant to §240.14a-12                                     |

#### BWX TECHNOLOGIES, INC.
<div align='center'>(Name of registrant as specified in its charter)

(Name of person(s) filing proxy statement, if other than the registrant)</div>

Payment of Filing Fee (Check the appropriate box):

| ý |     | No fee required.                                                         |
| ☐ |     | Fee paid previously with preliminary materials.                          |
| ☐ |     | Fee computed on table below per Exchange Act Rules 14a-6(i)(1) and 0-11. |