X0306 4 2015-05-13 0 0000935494 NATIONAL INSTRUMENTS CORP /DE/ NATI 0001574827 Starkloff Eric Howard C/O NATIONAL INSTRUMENTS CORPORATION 11500 NORTH MOPAC AUSTIN TX 78759 0 1 0 0 Executive Vice President Common Stock 2015-05-13 4 S 0 1675 29.006 D 9747 D David G. Hugley as attorney-in-fact for Eric H. Starkloff 2015-05-13