S&P and Dow stock index futures extended losses and Nasdaq futures briefly turned negative on Thursday after weak jobless data.

S&P 500 futures fell 3.8 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 shed 49 points, while Nasdaq 100 futures were up 1 point.

(Reporting by Edward Krudy; editing by Jeffrey Benkoe)