Stock index futures added to gains in choppy trade on Thursday after data showed new U.S. claims for unemployment benefits fell last week while U.S. nonfarm productivity increased during the third quarter.

S&P 500 futures rose 9.4 points and were above fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration of the contract. Dow Jones industrial average futures gained 90 points, and Nasdaq 100 futures rose 6.5 points.

(Reporting by Chuck Mikolajczak; editing by Jeffrey Benkoe)