Futures lower, investors look ahead to GDP data

NEW YORK (Reuters) - U.S. stock index futures were slightly lower on Thursday as investors looked ahead to a report on economic growth and continued to digest recent comments from the Federal Reserve.

* An advance read on third-quarter gross domestic product will be released at 8:30 a.m. (1230 GMT) and is seen showing economic growth slowed to 3 percent from 4.6 percent in the second quarter. The level of growth, which is expected to have been boosted by business spending, will be especially scrutinized a day after the Federal Reserve ended its stimulative bond-buying program.

* Without quantitative easing - which fueled market gains over recent years, though its end was widely expected - investors are looking to when the central bank will begin raising interest rates. The Fed has said its first rate hike would be dependant on the strength of economic data.

* A release on jobless claims is also on tap; claims are seen as unchanged from the previous week.

* In comments released after a two-day meeting, the U.S. central bank expressed confidence in U.S. economic prospects and dropped a characterization of U.S. labor market slack as "significant," which many traders took as indicating a more hawkish tone. The end to the quantitative easing program, which has fueled equity gains in recent years, was expected.

* Equities were volatile following the Fed's comments, with major indexes at one point trading sharply lower before rebounding. The S&P 500 is up 6.4 percent over the past nine sessions, and at its session low on Wednesday found support near its 50-day moving average, a sign that the trend remains positive.

* Dow component Visa Inc late Wednesday reported adjusted earnings that topped expectations, and said the mobile payment industry would be "a great driver" for business.

* So far this reporting season, 75.3 percent of S&P 500 companies have exceeded profit expectations, according to Thomson Reuters data, above the long-term average of 63 percent.

Futures snapshot at 6:57:

* S&P 500 e-minis were falling 8.5 points, or 0.43 percent, with 171,919 contracts changing hands.

* Nasdaq 100 e-minis were down 17.75 points, or 0.44 percent, in volume of 29,975 contracts.

* Dow e-minis were down 58 points, or 0.34 percent, with 24,597 contracts changing hands.

(Editing by W Simon)