X0306 4 2018-02-08 0 0000935494 NATIONAL INSTRUMENTS CORP NATI 0001192886 LE DUY LOAN T C/O NATIONAL INSTRUMENTS CORPORATION 11500 NORTH MOPAC AUSTIN TX 78759 1 0 0 0 Common Stock 2018-02-08 4 P 0 1900 46.56 A 89666 D The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $46.5599 to $46.57, inclusive. The reporting person undertakes to provide to National Instruments Corporation, any security holder of National Instruments Corporation, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the ranges set forth in this footnote to this Form 4. David G. Hugley as attorney-in-fact for Duy-Loan T. Le 2018-02-12