Stocks on Wall Street and in Europe surged on Wednesday after remarks from a Federal Reserve official stirred stimulus hopes and after the European Central Bank kept the door open to making a future cut to its benchmark interest rate.


The Dow and the broader indexes recorded their best daily performances this year. The Dow closed up 2.4 percent, or about 287 points, bringing its year-to-date gain back into positive territory. The Standard & Poor’s 500-stock index gained 2.3 percent for the day, and the Nasdaq composite rose 2.4 percent.


Earlier, European stocks closed sharply higher, with the Euro Stoxx 50 and indexes in Germany, France, Spain and Britain up more than 2 percent.


Mario Draghi, the European Central Bank president, said that some of the 23 members of the central bank’s governing council had argued for an interest rate cut in advance of Wednesday’s decision to stand pat on rates, and he left open the option of a cut later on. “We will stand ready to act,” he said.


The central bank also promised to continue to provide European Union commercial banks with effectively unlimited low-interest loans, at least through the end of 2012. That move came as Mr. Draghi noted the increased level of stress in Europe and signs of flagging growth.


Howard Archer, IHS Global Insight’s chief British and European economist, said there were “clear indications that an interest rate cut is now in the cards” because Mr. Draghi had stated that a “few” governing council members favored a cut in discussions leading up to Wednesday’s inaction.


 “We expect the E.C.B. to deliver an interest rate cut to 0.75 percent in July,” Mr. Archer wrote in a research commentary.


Rick Bensignor, the chief markets strategist for Merlin, said Mr. Draghi’s remarks that he stands ready to act if things get worse also could have helped stocks.


Other analysts noted that a rate cut on Wednesday would have had a limited impact because short-term rates are already close to zero.


Stocks also may have been buoyed after Dennis Lockhart, president of the Atlanta Federal Reserve, signaled that stimulus was still an option.


In a speech in Florida on Wednesday, Mr. Lockhart said that if needed to help growth in the United States, “further monetary actions to support the recovery will certainly need to be considered.”


Bond prices fell, pushing the United States 10-year Treasury yield up 8 basis points to 1.652 percent.


Energy and financial stocks rose the most among the S.&P. 500’s sectors, with gains of about 3 percent and 2.6 percent, respectively.


Crude oil futures rose in New York trading, by almost 1 percent.


In currency markets, the euro rebounded from just below $1.2450 to back above $1.2510. A currency analyst, Christopher Vecchio of DailyFX, said Mr. Draghi’s remarks that the E.C.B. was watching economic conditions closely also contributed to stoking the “risk-on” rally.


“Over all, it’s difficult to say that President Draghi was optimistic,” Mr. Vecchio wrote. “He noted that ‘euro-area growth remains weak’ and that the ‘economic outlook is subject to downside risks.’”


The central bank president also mentioned market tensions and unemployment weighing on the euro zone.


“While these may be the prevailing facts, hope seems to be what’s driving trading activity,” Mr. Vecchio wrote.