* Apple edges higher after results, revenue outlook
* Aetna earnings miss expectations, U.S. Steel swings to loss
* Retail sales unexpectedly dip 0.1 percent in September
* Futures up: Dow 3 pts, S&P 2.3 pts, Nasdaq 2.75 pts
NEW YORK, Oct 29 (Reuters) - U.S. stock index futures pointed to a flat open on Tuesday, suggesting the market's recent rally may have run out of steam as earnings fail to be another reason to buy with stocks near record highs.
Equities have been on a tear for the past couple weeks, with the benchmark S&P 500 climbing more than 6 percent on expectations the Federal Reserve will keep its stimulus in place when its policy committee meets Tuesday and Wednesday.
That policy, which has fueled the market's advance throughout the year, has been enough to offset an earnings season with seemingly as many disappointments as bright spots.
In economic news, U.S. retail sales dipped 0.1 percent in September, compared with economists' expectations of a 0.1 percent increase. Producer prices rose 0.1 percent in September, as expected.
"There's a lot of buyer's fatigue in the market right now. We're up more than 20 percent this year, markets have been through a lot, and we're sitting at all-time highs. No one wants to over-commit in that environment," said Oliver Pursche, president of Gary Goldberg Financial Services in Suffern, New York.
Apple Inc, the most valuable U.S. company by market cap, late Monday posted a decline in its fourth-quarter earnings and margins. However, the tech company also forecast first-quarter revenue of $55 billion to $58 billion, compared with expectations for $55.65 billion. Shares rose 0.4 percent to $532 in premarket trading.
With half of S&P 500 companies having reported, 69.1 percent have topped profit expectations, above the long-term average of 63 percent, according to Thomson Reuters data. However, only 53.9 percent have beaten revenue estimates, below the 61 percent rate since 2002.
S&P 500 futures rose 2.3 points and were above 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 added 3 points and Nasdaq 100 futures rose 2.75 points.
The S&P has climbed 6.4 percent since Oct. 8, when it hit its lowest point during the U.S. government's partial shutdown and the debate over raising the debt ceiling. The benchmark index is up 23.6 percent for the year so far, the best annual gain since 2003, after hitting a series of all-time highs. The Dow is less than 1 percent away from its all-time closing high.
The gains may make further advances harder to come by, especially with earnings struggling to serve as broader market catalysts.
Pfizer Inc reported third-quarter earnings that beat expectations, though global sales fell 2 percent. Shares of the Dow component fell 1.2 percent to $30.38 in premarket trading.
Aetna Inc reported adjusted third-quarter earnings that missed expectations and gave a full-year profit outlook that was largely below estimates.
U.S. Steep Corp late Monday swung to a third-quarter loss, hurt by a goodwill impairment charge, while Seagate Technology Plc reported first-quarter earnings and sales that missed expectations and gave a revenue outlook that was also below consensus.
U.S. Steel fell 0.9 percent to $23.20 before the bell while Seagate sank 4.2 percent to $47.75.
In company news, Michael Kors rose 3.2 percent in premarket trading after Standard & Poor's said the company would be added to the S&P 500 as of Nov. 1, replacing NYSE Euronext .