Stock index futures erased gains, with the S&P 500 and the Dow turning negative on Wednesday as early optimism over a report the IMF would increase its lending facility proved short-lived.

S&P 500 futures fell 1.3 points and were below fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration of the contract. Dow Jones industrial average futures lost 14 points, but Nasdaq 100 futures rose 3 points.

(Reporting By Edward Krudy; editing by Jeffrey Benkoe)