Super Micro joined the S&P 500 in March, and its stock is the best performer in that index on the year, up 200%. Read: Super Micro and Nvidia lead the S&P 500 this year. These stocks follow.

Server maker Super Micro Computer (SMCI) has undergone a 10-for-1 stock split and the company’s shares will begin trading at a lower price when markets open on October 1. The stock split takes ...