(Corrects moving average period to 14-day, not 50, in paragraph 3)
* Officials' remarks raise concern over stimulus pullback
* S&P 500's 50-day moving average seen as support level
* Walt Disney dips after results, Time Warner rises
* Futures down: Dow 46 pts, S&P 500 4.6 pts, Nasdaq 5 pts
By Ryan Vlastelica
NEW YORK, Aug 7 (Reuters) - U.S. stock indexes were set for a lower opening on Wednesday as concerns grew over the timing of the end of the Federal Reserve's stimulus policy.
Shares suffered their biggest daily decline since June 24 on Tuesday after comments from a pair of Fed officials muddied the water over how soon the central bank might reduce a stimulus policy widely credited with fueling the S&P 500's 19-percent gain this year.
Before the comments, equities had struggled for direction, with major indexes hovering near all-time highs with few clear catalysts to drive shares decisively higher still. While the uncertainty could spur investors to take profits, the S&P might find support at 1,693.95, its 14-day moving average.
"I'd be very wary of expecting additional gains in the market at these levels," said Tim Speiss, head of personal wealth advisors at EisnerAmper in New York. "I'm expecting a lot of volatility ahead, and maybe a sharp decline."
Chicago Fed President Charles Evans said Tuesday the Fed would probably scale back its bond-buying program later this year, perhaps beginning to do so as early as next month depending on economic data.
Those comments echoed earlier ones by Dennis Lockhart, president of the Federal Reserve Bank of Atlanta, though he told Market News International the Fed might continue its stimulus program if growth doesn't meet its targets.
Equity markets have been closely tethered to central bank policy, with many investors concerned that economic growth isn't robust enough to boost markets without the Fed's help. Last week, the July payroll report came in much weaker than expected.
"No one wants the Fed to stop purchasing (bonds) too soon, and there's a concern that if it stops, there could be a slowdown in the economy," said Speiss.
Walt Disney Co fell 1.9 percent to $65.80 in premarket trading. On Tuesday, it projected a massive loss related to its summer film, "The Lone Ranger," though adjusted earnings slightly beat expectations.
S&P 500 futures fell 4.6 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 slid 46 points and Nasdaq 100 futures lost 5 points.
Time Warner Inc shares rose 3.3 percent to $66.20 in premarket trading after the company reported a bigger revenue than had been forecast. AOL Inc rose 3.9 percent to $37.60 before the bell after it reported results and said it would buy Adap.tv, a video ad platform, for $405 million.
On the downside, First Solar Inc fell 8.4 percent to $42.80 in premarket trading a day after it reported results that were below expectations and cut its full-year outlook. Ralph Lauren Corp shares fell 7.6 percent to $175.04 as profits declined.
Of the 418 companies in the S&P 500 that have reported earnings through Tuesday morning, Thomson Reuters data showed that 67.5 percent topped analysts' expectations, in line with the average beat over the past four quarters. On the revenue side, 54 percent have reported revenue above estimates, more than in the past four quarters but below the historical average.
Shares fell Tuesday after the comments from central bank officials, though volume was light for a second straight day.
(Editing by Bernadette Baum)