The tumbling euro and easy-money policies are boosting optimism in corporate Europe that the long-struggling region might finally begin a sturdy recovery. But Europe’s good fortune is a headache for U.S. corporate competitors that face a squeeze on overseas sales from the rising dollar.

“We’re cashing in,” said Massimo Vian, chief executive of Italian eyewear giant Luxottica , whose biggest market is North America. Fourth-quarter sales in North America rose 12% on the year in U.S. dollars, whose strength means rising profits in euros. “If it continues this way, we’ll consider whether to lower prices or increase the number of store openings or even increase investments,” he said.

It remains unclear whether the weak euro, monetary stimulus and cheap energy prices will be enough to lift the eurozone Europe’s common-currency area out of its prolonged growth malaise. Europe and Japan saw scant lasting impact on growth when their currencies swooned in the 1990s. And a lower currency doesn’t immediately translate into lower export prices. In the U.S., import prices from the European Union are down just 2.7% over the past year, despite the euro’s sharp decline.

But business leaders, economists and policy makers are convinced the euro’s drop is helping turn the tide at least a bit in Europe’s favor.

American corporations with major foreign revenues, meanwhile, are finding it harder to compete in export markets, and some worry the euro’s slide is far from over.