Stock index futures added to earlier gains on Wednesday after a gauge of manufacturing in New York State picked up in February to its highest level in more than 1-1/2 years.

S&P 500 futures rose 6.5 points and were above 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 added 44 points and Nasdaq 100 futures rose 12.5 points.

(Editing by Jeffrey Benkoe)