Stocks opened flat in the United States after a surge in shares in Asia that carried over into Europe.

The three main gauges were essentially unchanged, fluctuating in and out of positive territory.

Asian stock markets rebounded earlier in the day from a sell-off on Friday as investors’ appetite for equities returned after the Federal Reserve reduced its discount rate.

The Tokyo benchmark Nikkei index rose 3 percent, recovering more than half of Friday’s 5.42 percent decline. Australia’s benchmark S&P/ASX 200 rose 4.6 percent in its biggest one-day gain in almost a decade and other markets in the region, including Hong Kong, New Zealand, South Korea and Taiwan also gained.

That rally carried over into Europe, extending gains that began after the Fed’s move. The Dow Jones Stoxx 600 index rose 1.1 percent, to 364, in London. It dropped 9.1 percent from a six-and-half-year high on June 1 after investors began to worry that defaults among American borrowers with poor credit profiles might spread to other asset classes.

Some investors in Europe today returned to riskier assets, such as equities, in hope of finding bargains. Alex Lyle, a fund manager at Threadneedle Investments, said that recent market weaknesses could offer investment opportunities for the long-term with price to earnings ratios at around their lowest levels in the last 15 years.

European banks and insurers, including UBS and Prudential, saw gains as investors concluded that recent declines in the stocks of financial institutions were out of line with their robust earnings this year. Stocks of financial-services companies in Europe’s Stoxx 600 index have declined 11 percent in the past month. In Asia, Macquarie, Australia’s largest securities firm, had its biggest one-day gain in a decade.

Mining stocks also rose. BHP Billiton, the world’s biggest mining company, gained 4.9 percent to 12.8 pounds, and Rio Tinto, the third-biggest, rose 4.7 percent to 31.2 pounds.

National benchmarks increased in all 18 western European markets except Luxembourg. Britain’s FTSE 100 added 1 percent while Germany’s DAX index gained 0.5 percent and France’s CAC 40 advanced 1.2 percent.

Other analysts, including Albert Edwards at Dresdner Kleinwort in London, saw today’s stock market increase as a “knee-jerk” reaction to the Federal Reserve’s discount rate reduction and said the risk of a recession remains “extremely high.”

“Nothing goes down in a straight line,” Mr. Edwards said. “Rallies after Fed cuts are quite normal, but that can change quickly after we get the next bad news. And that is inevitable.”