Stock index futures cut gains sharply on Thursday after a report in German newspaper Die Welt said the German government does not rule out the possibility of postponing a European Union summit planned for this Sunday.

S&P 500 futures added 0.3 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 18 points, and Nasdaq 100 futures fell 2.5 points.

(Reporting by Ed Krudy, Editing by Chizu Nomiyama)