Form 3 Filing for NPK International Inc.

This filing reports initial ownership of securities by Matthew James Warren, Chief Accounting Officer of NPK International Inc. As of August 31, 2026, Mr. Warren directly owns 54,430 shares of Common Stock. This total includes 21,066 time-based restricted stock units that will settle for shares upon vesting. The filing was signed by M. Celeste Fruge on behalf of Matthew Warren on September 8, 2026.