The current institutional shareholding score of NPK International Inc is 10.00, ranking 1 out of 100 in the Oil & Gas Related Equipment and Services industry. The latest institutional shareholding proportion is 98.33%, representing a quarter-over-quarter increase of 6.58%. The largest institutional shareholder is Chuck Royce, holding a total of 1.97M shares, representing 2.45% of shares outstanding, with 0.10% decrease in holdings.