U.S. stock index futures extended declines on Thursday after data showed initial claims for jobless benefits unexpectedly rose last week.

* S&P 500 futures dropped 11.2 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 fell 90 points, and Nasdaq 100 futures lost 11.75 points.

(Reporting by Leah Schnurr; editing by Jeffrey Benkoe)