U.S. stock index futures held their gains on Thursday after U.S. economic data had the U.S. economy growing 2.8 percent in the third quarter and jobless claims falling last week, with Wall Street on track to extend its record advance.

Stock futures had turned positive after the European Central Bank surprised traders by cutting its key interest rate in a bid to fend off the potential danger of deflation. Though the rate cut was not entirely unexpected, market consensus had been that the ECB probably would wait until its next meeting to cut. The bank's move to lower the rate to 0.25 percent was enough to give a substantial boost to futures, which had been trading around even or slightly negative before the 7:45 am ET announcement.