Stuck futures up on hopes stimulus to continue; Tesla stumbles By Chuck Mikolajczak NEW YORK (Reuters) - U.S. stock index futures rose on Wednesday on the possibility the Federal Reserve may keep stimulus measures in place longer than anticipated ahead of data key later this week on the labor market and economic growth. John Williams, president of the San Francisco Federal Reserve Bank, said Tuesday the Fed should wait for stronger evidence of economic momentum before pulling back on its massive bond-buying program, but should then announce a definitive end to the stimulus. Adding to speculation about a more dovish Fed, two of the Federal Reserve's top staff economists made the case in new research papers for more aggressive action by the U.S. central bank to drive down unemployment by promising to hold interest rates lower for longer. Many market participants have expected the Fed to hold off on scaling back its $85 billion monthly bond purchases due to expectations that a partial government shutdown in early October has hurt the economy. The S&P 500 .SPX is up 23.6 percent for the year, putting it on track for its best yearly performance since 2003, boosted in large part by the Fed's stimulus measures. S&P 500 futures rose 8.8 points and were above fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures gained 67 points and Nasdaq 100 futures added 12.25 points. Tesla Motors Inc (TSLA.O) shares slumped 11.1 percent to $157.15 before the opening bell after the electric car maker forecast a weaker-than-expected fourth-quarter profit and posted third-quarter Model S deliveries that disappointed some analysts. Microsoft Corp (MSFT.O) edged up 0.6 percent to $36.85 in premarket trading after sources familiar with the matter said the world's largest software maker had narrowed its list of external candidates to replace Chief Executive Steve Ballmer to about five people, including Ford Motor Co (F.N) chief Alan Mulally and former Nokia (NOK1V.HE) CEO Stephen Elop. As earnings season moves into its tail end, S&P companies expected to report earnings on Wednesday include Qualcomm Inc (QCOM.O) and Whole Foods Market Inc (WFM.O). According to Thomson Reuters data, of 404 companies in the S&P 500 that reported results through Tuesday morning, 69.6 percent beat Wall Street's expectations, above the long-term average of 63 percent. However, just 53.3 percent beat revenue forecasts, below the 61 percent average since 2002. European shares rose, erasing the previous session's losses, on better-than-expected results. .EU Most Asian markets were little changed amid uncertainty over monetary policy in the United States and Europe, though Japanese stocks rose, thanks to gains in major car makers.