Company: IPGP
Filing Date: 2025-05-21
Form Type: S-8 POS
Source: 0001111928-25-000085
Chunk: 1

Company: IPG PHOTONICS CORP
Filing Date: 2025-05-21
Form: S-8 POS
Chunk 1
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617) 570-1000</div>

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

| Large Accelerated Filer |     | ☑ |     | Accelerated Filer         |     | ☐ |
| Non-Accelerated Filer   |     | ☐ |     | Smaller Reporting Company |     | ☐ |
| Emerging Growth Company |     | ☐ |     |                           |     |   |

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☐

### EXPLANATORY NOTE
This Post-Effective Amendment No. 1 (the “Post-Effective Amendment”) relates to the following registration statements on Form S-8 (collectively, the “Registration Statements”) filed by IPG Photonics Corporation (the “Registrant”):

— Registration Statement No. 333-139509 filed with the U.S. Securities and Exchange Commission (the “SEC”) on December 20, 2006 registering 4,000,000 shares of the Registrant's common stock, par value $0.0001 per share (“Common Stock”), issuable under the IPG Photonics Corporation 2006 Incentive Compensation Plan, as amended and restated (the “2006 Plan”).

— Registration Statement No. 333-177818 filed with the SEC on November 8, 2011 registering 6,084,273 additional shares of Common Stock under the 2006 Plan.

— Registration Statement No. 333-206931 filed with the SEC on September 14, 2015 registering 279,192 additional shares of Common Stock under the 2006 Plan .

— Registration Statement No. 333-273640 filed with the SEC on August 3, 2023 registering 1,200,000 additional shares of Common Stock under the 2006 Plan.

The Registrant's Board of Directors approved the IPG Photonics Corporation 2025 Incentive Compensation Plan (the “202