NEW YORK - The slumping dollar has become a financial lifesaver for U.S. companies whose overseas operations in many cases are growing faster than their domestic units. It also helps explain why U.S. stocks have zoomed to records even as signs of an economic slowdown have multiplied.

Companies such as Caterpillar Inc., McDonald's Corp. and General Electric Co. reported first-quarter earnings last week that surprised most Wall Street analysts precisely because of better-than-expected results from Europe, Latin America and Asia.

The dollar fell Friday to an all-time low against the euro, the currency used in Germany, France, and 11 other European nations. The dollar has not plunged this far vs. the pound since Margaret Thatcher's second year as prime minister. That means profits earned in those nations become supercharged when they are converted into dollar equivalents for financial reporting.

"What these companies are earning outside the U.S. is worth a lot more, it is like getting a free ride on the currency movement," said Octavio Marenzi, chief executive officer of Celent L.L.C., a business consultant. For now, "lots of corporations are looking much better than they'd otherwise look."

Caterpillar had a tough time during the first quarter winning orders for its big yellow bulldozers and other construction equipment on U.S. soil. Left tattered by the U.S. housing slump, Caterpillar said its first-quarter profit slid 3 percent from the year-earlier period.

But that was a better result than Wall Street was expecting, in large part because of a sales surge outside the United States that pushed overall revenue to $10 billion, 7 percent higher than a year earlier. Chief executive Jim Owens credited "exceptional growth outside North America," which prompted the Illinois company to boost its 2007 profit and revenue projections.

General Electric Co. chief executive Jeffrey Immelt said his strategy of selling power-plant and aviation equipment outside the United States had paid off. Profit rose 2 percent, but the real story was that revenue surged 6 percent to $40.2 billion.

The biggest slice of GE's sales came from overseas, where revenue rose 9 percent to $19.6 billion. Sales in developing markets surged 14 percent to $7 billion.

One U.S. multinational company where the dollar's impact has had a potent effect is McDonald's. The Oak Brook, Ill., fast-food chain operates in more than 100 countries and sells burgers in dozens of different currencies.

With sales slowing in the United States, McDonald's relied more heavily on its European restaurants for growth. McDonald's said sales at restaurants open at least 13 months, a key retail measure known as same-store sales, rose 6.3 percent for the quarter.

Same-store sales were up 4.4 percent in the United States, 8 percent in Europe, and 8.5 percent in the company's Asia-Pacific business. Meanwhile, gains from currency translation accounted for 4 percent of the company's overall revenue, or about $224 million.