* S&P 500 ends eight-day rally, but stays above 1,500
* Yahoo rises after results, Ford shares volatile
* Futures down: Dow 20 pts, S&P 3.9 pts, Nasdaq 5.25 pts
NEW YORK, Jan 29 (Reuters) - U.S. stock index futures pointed to slight losses at the open on Tuesday as investors took profits following an extended rally and looked for confirmation the gains could continue.
Equities have been on a tear lately, with the S&P 500 ending an eight-day streak of gains in Monday's session. The index remained above 1,500, suggesting there was still support for a market that has been hovering around five-year highs.
"We need to slow down and digest the huge move we've had, so it makes sense futures are weak this morning, though it is also encouraging that we're still strong enough to stay above 1,500," said Christian Wagner, chief executive officer at Longview Capital Management in Wilmington, Delaware.
The gains have largely come on a strong start to earnings season and that trend continued on Tuesday, with positive earnings from Ford Motor Co and Pfizer Inc.
Both companies reported profits that topped expectations, though Ford also forecast a wider loss in its European segment. After climbing more than 4 percent, it turned lower to fall 1.7 percent to $13.54 before the bell.
Pfizer, a Dow component, rose 0.7 percent to $27.03 after its results. Eli Lilly and Co, another pharmaceutical company, was flat after reporting adjusted fourth-quarter earnings and revenue that beat expectations.
Yahoo Inc rose 2.7 percent to $20.86 in premarket trading a day after reporting adjusted earnings that beat expectations and forecasting a rise in annual revenue.
"We've had some cross-currents on earnings, with both strength and weakness, and that's another reason we need some affirmation the upside will continue from here," said Wagner.
Thomson Reuters data showed that of the 150 companies in the S&P 500 that have reported earnings so far, 67.3 percent have beaten analysts' expectations, which is a higher proportion than over the past four quarters and above the average since 1994.
S&P 500 futures fell 3.9 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 fell 20 points and Nasdaq 100 futures slid 5.25 points.
The Federal Reserve's Open Market Committee begins two days of meetings on interest rates. Traders speculated more solid U.S. growth might see the Fed pull back on its aggressive easing stimulus, which has played a key role in fuelling an equity market rally since the second half of last year.
In a sign of the improved view towards equities, investors poured $55 billion in new cash into stock mutual funds and exchange-traded funds in January, the biggest monthly inflow on record, research provider TrimTabs Investment Research said.
Home prices rose 0.6 percent in November, as expected, according to the S&P Case/Shiller Home Price Index. The news comes a day after data showed an unexpected drop in December pending home sales.
Futures were little impacted by the Case/Shiller report. January consumer confidence is due at 10 a.m. (1500 GMT) and is seen dipping to 64 from 65.1 in the previous month.
U.S. stocks edged modestly lower on Monday. However, Caterpillar Inc rallied after results, limiting losses in the Dow, while a rebound in shares of Apple Inc kept the Nasdaq in positive territory.