 Shareholders of Digital Turbine Inc NASDAQ:APPS, Mechanical Technology Inc NASDAQ:MKTY and Silvergate Capital Corp NYSE:SI have seen the value of their holdings increase significantly in recent years, outperforming the SP 500 Index. The share price of the benchmark index for the U.S. market 4,073.94 as of April 6 has gained 53 over the past year, 56 over the past three years and 99 over the past five years through April 6. 