Stock index futures pointed to a lower open on Tuesday on concerns about the state of corporate profits after several major U.S. companies reported disappointing quarterly results and even cloudier outlooks.

Caterpillar Inc shares slipped 4.4 percent to $29.15 in premarket trade after the world's No. 1 maker of building equipment posted first-quarter results and said it will suspend share repurchases.

Chemical maker DuPont Co reported a 59 percent fall in quarterly earnings, cut its full year 2009 profit forecast due to weak demand, and said it will cut costs further.

Bank of New York Mellon Corp said first-quarter profit fell by more than one-half as fees tumbled, and the bank slashed its dividend 63 percent in an effort to build capital. Its shares fell 5.8 percent to $26.41 in premarket trade.

We're going to get a lot of earnings today. That's going to dominate a lot of the activity after yesterday's massive profit taking following Friday's options expiration, said Paul Mendelsohn, chief investment strategist at Windham Financial Services in Charlotte, Vermont.

Now we are going to get a much better picture across multiple sectors and across the entire market and that will give us a picture of what the economy has been doing in the first quarter.

S&P 500 futures dropped 6.20 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 65 points, and Nasdaq 100 futures fell 5.50 points.

Drugmaker Merck & Co Inc , which plans to buy rival Schering-Plough Corp later this year, reported lower-than expected sales and earnings and cited the global economic slowdown.

Diversified U.S. manufacturer United Technologies Corp reported a 27.8 percent fall in quarterly profit as the slumping economy crimped demand for its jet engines and air conditioners. Shares were down slightly at $45.78.

Soft drink maker Coca-Cola Co shed 1.3 percent to $43.76 after posting first-quarter results that included a 3 percent drop in revenues.

At the close of trading on Friday, the blended growth rate for the first quarter, which combines actual numbers for companies that have reported earnings and estimates for companies that have yet to report, stood at negative 37.4 percent, according to Thomson Reuters data.

Shares of General Motors Corp jumped 11.5 percent in premarket trade after an independent oversight report on the Treasury Department's corporate rescue fund said the Obama administration will make up to $5 billion available to GM through May and will also make $500 million available to Chrysler as it seeks to reach an alliance with Fiat .

Stocks slid more than 3 percent on Monday after weak results from Bank of America Corp reignited concerns over the state of the banking industry and the economy.

European shares were lower in choppy trade as declines in bank stocks offset gains in defensives, led higher by record earnings from British retailer Tesco Plc .

(Reporting by Chuck Mikolajczak; Editing by Theodore d'Afflisio and Jeffrey Benkoe)