X0609 4 2026-06-01 0 0000071829 NPK International Inc. NPKI 0001880836 Briggs Lori false 9320 LAKESIDE BOULEVARD SUITE 100 THE WOODLANDS TX 77381 0 1 0 0 VP & President, Ind. Solutions 1 Common Stock 2026-06-01 4 F 0 5401 14.31 D 257950 D Common Stock 2026-06-01 4 F 0 9577 14.31 D 248373 D Common Stock 2026-06-01 4 F 0 6777 14.31 D 241596 D Common Stock 2026-06-01 4 M 0 24340 0.0 A 265936 D Common Stock 2026-06-02 4 S 0 10446 14.5776 D 255490 D Restricted Stock Units 0.0 2026-06-01 4 M 0 24340 0.0 D Common Stock 24340 0 D Represents shares withheld to satisfy tax withholding obligations upon the vesting of restricted stock units. The restricted stock units vest and convert into shares on a one-for-one basis. The reported sale of 10,446 shares occurred automatically pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on December 15, 2025. The price reported is the weighted average price. These shares were sold in multiple transactions in the open market at prices ranging from $14.33 to $14.74, 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. Grant of restricted stock units that vest in one-third increments on June 1 of each subsequent year after grant and settle in shares. By: M. Celeste Fruge For: Lori Briggs 2026-06-03