Stock index futures sharply added to gains on Friday ahead of key U.S. jobs data and as traders and analysts cited a report that the European Central Bank was gearing up to lend money to the International Monetary Fund in a bid to ease a euro zone debt crisis.

S&P 500 futures jumped 16.7 points and were 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 rose 153 points, while Nasdaq 100 futures added 30 points.

(Editing by Padraic Cassidy)