Wall Street was set to open lower on Tuesday after 3M Co's outlook for the current year came in below analysts' forecast and McDonald's Corp reported a second straight month of declines in domestic sales.

Equity futures were under pressure on a number of fronts. The U.S. dollar was broadly stronger after more worries about the developing debt situation in Dubai hit overseas stock markets, and commodity prices slipped. Comments from ratings agency Moody's also highlighted the fragility of the economic recovery.

The combination of some negative corporate news, the strengthening of the dollar and the exiting of commodities is weighing on the futures pre-open, said Peter Cardillo, chief market economist at Avalon Partners in New York.

3M fell 2 percent to $76.29 before the opening bell after the diversified manufacturer forecast 2009 earnings per share, excluding items, between $4.50 and $4.55 per share. The consensus of analysts polled by Thomson Reuters is for earnings of $4.57 a share.

Shares of McDonald's Corp slid 2.4 percent to $60.45 after it said sales at established U.S. restaurants dipped in November, the second straight month of declines at domestic outlets.

Oil fell below $73 a barrel, extending the previous day's 2 percent decline. The dollar <.DXY>, which has traded inversely to stocks of late, firmed 0.3 percent against a basket of currencies.

FedEx Corp could help limit losses after it said late on Monday its second-quarter earnings would easily beat its previous forecast, citing strong growth in international demand for its air services, especially in Asia and Latin America. Its shares gained 2.1 percent to $89.40 premarket.

S&P 500 futures fell 8.8 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 slipped 74 points, while Nasdaq 100 futures dipped 15.25 points.

The S&P 500 and Nasdaq ended slightly lower on Monday and the Dow was flat, reversing earlier gains following comments from Federal Reserve Chairman Ben Bernanke that sparked jitters about the pace of the economic recovery.

Moody's Investors Service said the global economic and financial crises may be close to an end, but the fiscal crisis in a number of top-rated countries could last for several years.

Investors were also watching developments in Dubai as its leaders dithered over a rescue for debt-laden company Dubai World. The firm had said in late November it needed a six month standstill on payments, but a government official said on Tuesday it would need more time than that.

(Editing by Padraic Cassidy.)