X0306 4/A 2012-05-01 2012-05-02 0 0000935494 NATIONAL INSTRUMENTS CORP /DE/ NATI 0001192886 LE DUY LOAN T C/O NATIONAL INSTRUMENTS CORPORATION 11500 NORTH MOPAC, BLDG B AUSTIN TX 78759 1 0 0 0 Common Stock 2012-05-01 4 M 0 5305 A 52332 D Each restricted stock unit represents a contingent right to receive one share of the Issuer's common stock. The amount of securities beneficially owned was erroneously reported as 47,332. David G. Hugley as attorney-in-fact for Duy-Loan T. Le 2013-04-26