NEW YORK (Reuters) - S&P 500 index futures erased gains and turned negative on Friday after weaker-than-expected revenue from Bank of America Corp , Citigroup Inc , General Electric Co .
S&P 500 futures were down 0.6 points and below 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 7 points, and Nasdaq 100 futures added 2.5 points.
(Reporting by Angela Moon; Editing by Padraic Cassidy)
