Joel Greenblatt acquired 220 Thousand National Instruments shares worth $13.2 Million. That's 0.23% of their equity portfolio (59th largest holding). The investor owns Inf% of the outstanding National Instruments stock. The first National Instruments trade was made in Q2 2014. Since then Joel Greenblatt bought shares five more times and sold shares on seven occasions. The stake costed the investor $13.1 Million, netting the investor a gain of 0.7% so far.