The S&P 500's newest tech stock is now its best performer

By Emily BaryShares of data-storage company Everpure were leading S&P 500 gainers on ThursdayEverpure's stock was up 18% on Thursday.Everpure made it to the big leagues earlier this month when it was added to the S&P 500, and now the data-storage company is making a name for itself.Shares of Everpu…