(Reuters) - Stock index futures pointed to a firmer open on Wall Street on Thursday, with futures for the S&P 500 up 0.3 percent, while Dow Jones and Nasdaq 100 futures gained around 0.4 percent each by 3.57 a.m. EDT.

The S&P 500 touched its highest level since early May on Wednesday and closed up 9.11 points, or 0.67 percent, at 1,372.78 .SPX. The Dow Jones industrial average .DJI gained 103.16 points, or 0.81 percent, to 12,908.70. The Nasdaq Composite Index .IXIC added 32.56 points, or 1.12 percent, to 2,942.60.

Gains in Asia .N225 and Europe have followed, with the FTSEurofirst 300.FTEU3 up 0.5 percent by 3.52 a.m. EDT.

With the corporate earnings season in full flow, shares in IBM (IBM.N) dropped 1.1 percent after the bell as it posted a quarterly revenue shortfall. But the computing firm also raised its full-year earnings target.

KFC parent Yum Brands Inc (YUM.N) reported quarterly profit that missed Wall Street's view as inflation in China cut into margins in that country, its top market, taking its shares lower after hours.