Stock index futures edged higher on Thursday but trading was highly volatile as traders reacted to developments from the European Central Bank, including moves to ease bank financing and a decision not to lower interest rates as some investors had hoped for.

S&P 500 futures rose 3.2 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 added 39 points and Nasdaq 100 futures put on 9.25 points.