X0609 4 2026-08-27 0 0000071829 NPK International Inc. NPKI 0001251678 ROBESON ROSE M false 9320 LAKESIDE BOULEVARD SUITE 100 THE WOODLANDS TX 77381 1 0 0 0 1 Common Stock 2026-08-27 4 S 0 10000 13.4917 D 215147 D The reported sale of 10,000 shares occurred automatically pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on May 27, 2026. The price reported is the weighted average price. These shares were sold in multiple transactions in the open market at prices ranging from $13.11 to $13.72, inclusive. The reporting person undertakes to provide to NPK International Inc., any security holder of NPK International Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in footnote (2) to this Form 4. By: M. Celeste Fruge For: Rose M. Robeson 2026-08-31