X0508 4 2026-01-12 0 0001111928 IPG PHOTONICS CORP IPGP 0001508155 Valentin Gapontsev Trust I 3 EXECUTIVE PARK DRIVE, SUITE 302 BEDFORD NH 03110 0 0 1 0 1 Common Stock 2026-01-12 4 S 0 16065 76.20 D 6843534 D Common Stock 2026-01-12 4 S 0 1928 76.69 D 6841606 D Common Stock 2026-01-13 4 S 0 16752 76.71 D 6824854 D Common Stock 2026-01-13 4 S 0 6277 77.70 D 6818577 D Common Stock 2026-01-14 4 S 0 3667 77.19 D 6814910 D Common Stock 2026-01-14 4 S 0 13159 77.63 D 6801751 D Common Stock 2026-01-14 4 S 0 700 78.55 D 6801051 D The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 13, 2025. The reported transaction involves sale transactions ranging from $75.47 to $76.45 per share. The weighted average price per share was $76.20. The Reporting Person undertakes to provide upon request by the SEC staff, the Issuer or a security holder of the Issuer, information regarding the number of shares sold at each separate price. The reported transaction involves sale transactions ranging from $76.61 to $76.82 per share. The weighted average price per share was $76.69. The Reporting Person undertakes to provide upon request by the SEC staff, the Issuer or a security holder of the Issuer, information regarding the number of shares sold at each separate price. The reported transaction involves sale transactions ranging from $76.29 to $77.24 per share. The weighted average price per share was $76.71. The Reporting Person undertakes to provide upon request by the SEC staff, the Issuer or a security holder of the Issuer, information regarding the number of shares sold at each separate price. The reported transaction involves sale transactions ranging from $77.31 to $78.00 per share. The weighted average price per share was $77.70. The Reporting Person undertakes to provide upon request by the SEC staff, the Issuer or a security holder of the Issuer, information regarding the number of shares sold at each separate price. The reported transaction involves sale transactions ranging from $76.31 to $77.30 per share. The weighted average price per share was $77.19. The Reporting Person undertakes to provide upon request by the SEC staff, the Issuer or a security holder of the Issuer, information regarding the number of shares sold at each separate price. The reported transaction involves sale transactions ranging from $77.31 to $78.22 per share. The weighted average price per share was $77.63. The Reporting Person undertakes to provide upon request by the SEC staff, the Issuer or a security holder of the Issuer, information regarding the number of shares sold at each separate price. The reported transaction involves sale transactions ranging from $78.34 to $78.75 per share. The weighted average price per share was $78.55. The Reporting Person undertakes to provide upon request by the SEC staff, the Issuer or a security holder of the Issuer, information regarding the number of shares sold at each separate price. /s/ Adam N. King, Attorney-in-Fact for Valentin Gapontsev Trust I 2026-01-14