Stock index futures pointed to a modestly lower open on Tuesday as a slew of corporate earnings failed to persuade investors to add to the previous session's gains.

Six Dow components have reported quarterly results since the close of trading on Monday, including 3M Co , Johnson & Johnson and American Express Co .

J&J fell 1.9 percent to $61.03 in premarket trading, pressured by lower-than-expected fourth-quarter sales, while 3M lost 1.7 percent to $88.75 despite posting a profit that topped expectations. It also raised its full-year outlook.

Stocks have had an incredible run, so it would take big beats on earnings to move things higher from here, and we haven't really seen that, said Michael O'Rourke, chief market strategist at the New York-based BTIG LLC.

I'm not expecting a steep selloff, but until these gains are consolidated it will be especially tough for us to move higher.

Equities have advanced in recent weeks, in part in anticipation of strong corporate results. Weak bank earnings last week contributed to a stalled rally, and the S&P ended a seven-week run of gains. On Monday, strength in tech and natural resource shares suggested a renewed sense of positive momentum.

DuPont Co

rose 0.9 percent to $49.35 before the bell, while Travelers Cos Inc added 2.6 percent to $57.07 after both topped earnings expectations. DuPont also raised its 2011 outlook, and Travelers said it will repurchase $5 billion more stock.

Verizon Communications Inc's profit and sales were slightly below estimates, and the stock slipped 0.4 percent to $35.10 before the bell.

S&P 500 futures fell 5.9 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 lost 25 points, and Nasdaq 100 futures dropped 13 points.

Shares of American Express Co and Texas Instruments Inc fell a day after reporting results. American Express was pressured by an uncertain regulatory outlook, while TI's gross margins disappointed investors. AmEx fell 1.9 percent to $44.91 before the bell, while TI slid 2.3 percent to $33.85.

The Conference Board will release its January reading on consumer confidence at 10 a.m. EST (1500 GMT) Economists see confidence rising slightly to 54.3 from December's 52.5.

The International Monetary Fund revised its forecast for world growth higher, citing the impact from a package on U.S. taxes.

U.S. President Barack Obama will give his annual State of the Union address Tuesday evening and is expected to focus on jobs and the economy.

Stocks rose Monday on strength in natural resource and technology shares as the recent positive momentum returned.

(Editing by Jeffrey Benkoe)