U.S. stock index futures pointed to a higher open on Tuesday as the fourth-quarter earnings season started with a stronger-than-expected profit from Alcoa and higher outlooks from several retailers.

Alcoa Inc , the first Dow component to report, posted a quarterly profit late on Monday that topped Wall Street's expectations, though revenue missed the analyst average estimate. Alcoa also forecast a 12 percent rise in demand this year.

The fact that Alcoa did so well sets the tone for the rest of the season, said Malcolm Polley, president and chief investment officer of Stewart Capital Advisors in Indiana, Pennsylvania. That revenue came in a little under expectations is a bit troublesome, but the fact that Alcoa's profit beat as well as it did despite that is certainly a positive.

Shares of the aluminum maker fell 1.6 percent to $16.23 in premarket trading but are up 25.5 percent since the start of December. Stocks rallied in recent weeks in part on hopes of a strong earnings season.

Homebuilder Lennar Corp rose 5.8 percent to $20 in premarket trading after posting a fourth-quarter profit sharply higher than expected.

Both Sears Holding Corp and Tiffany & Co raised their profit outlooks, citing strong sales. Sears rose 7.6 percent to $76 before the bell, and Tiffany rose 2.9 percent to $6275.

Supervalu Inc , the third-biggest U.S. supermarket chain, shed 6.2 percent to $8.06 after it reported a quarterly loss.

S&P 500 futures rose 5.5 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 47 points, and Nasdaq 100 futures rose 9.25 points.

The S&P has found technical support near its 14-day moving average, which is around 1,264. The index closed at 1,269.75 on Monday.

U.S. wholesale inventories for November will be reported at 10 a.m. (1500 GMT) on an otherwise light day for economic data. Inventories were expected to gain 1.0 percent after a 1.9 percent rise in October. Estimates for November ranged from 0.5-2.0 percent in a Reuters poll.

European shares rose 1 percent as reassuring comments from Portugal's prime minister eased worries about the country's debt level. U.S. and European stocks were pressured on Monday on concerns the country would need a bailout.

On Monday, U.S. stocks recovered most of their early losses in light volume to end slightly lower as prospects for strong earnings helped counter worries about Portugal.

(Editing by Padraic Cassidy)

Portugal