NEW YORK (CNNMoney.com) -- Stocks are poised to open significantly lower on Tuesday, as investors worry that the new stimulus plan - expected to be signed into law later in the day - won't help breathe new life into the economy.

At 5:25 a.m. ET, the Dow Jones industrial average, S&P 500 and Nasdaq futures were lower with a comparison to fair value, suggesting a dismal start on Wall Street.

Futures act as a general guide of how markets will likely open, measuring current index values against the perceived future performance.

U.S. markets were closed Monday in observance of President's Day.

Global markets on Tuesday were lower, with declines in the Asian and European indexes.

All eyes will be on President Obama, who is expected to sign the $787 billion stimulus bill into law sometime Tuesday, marking the final step for approval in what has been a contentious process and the first major challenge for the new president.

Enthusiasm over the stimulus plan and bank bailout have been tempered by an ongoing barrage of bad corporate and economic news. Last week, the Dow shed 5.2%, the S&P 500 fell 4.8% and the Nasdaq stumbled 3.6%.

Looking forward, the president on Wednesday is expected to unveil his long-awaited foreclosure prevention plan.

Companies: Wal-Mart Stores (WMT, Fortune 500) will report fourth-quarter earnings before the bell. Analysts expect the company to report a 2% gain in revenues to $109 billion, and a 5% decline in earnings to 99 cents per share, according to a consensus of analysts polled by Thomson Reuters.

Tuesday is also deadline day for General Motors (GM, Fortune 500) and Chrysler. The automakers, who have already received approval for $17.4 billion in loans from the government, will submit their latest financial survival plans to the Treasury Department.

Oil and money: Oil prices fell 56 cents a barrel in early trading to $36.45. The U.S. dollar rose against major currencies, including the euro, the yen and the British pound.