Wall Street surged higher in a volatile session yesterday, offsetting the losses it incurred Friday but showing more fractiousness than conviction in an advance that lifted the Dow Jones industrials 286 points, its biggest gain in nearly five years.

Investors tried to balance their concerns about the availability of credit with hopes that today’s Federal Reserve meeting will be a calming influence after two weeks of frenetic trading on Wall Street. In a day devoid of economic news and with few earnings reports, investors early in the session seemed to avoid making big bets, though stocks gained steam after midday and made their biggest advance in the final two hours.

Fed policy makers are widely expected to hold the nation’s benchmark rate steady at 5.2%; as usual, the greater concern is with the Fed’s economic assessment statement. This time, investors will be looking to see what the Fed says about credit.

The Dow’s biggest single-session point gain since October 2002 and its largest percentage gain since June 2003 follows a number of choppy sessions in which investor sentiment has vacillated between fear about lending to occasional bursts of optimism. Eight of the last 10 sessions have seen swings greater than 100 points in the Dow. The erratic activity has followed the stock market’s high seen July 19, when the Dow closed above 14,000 for the first time and the Standard & Poor’s 500 index also had a record close.

“I really wouldn’t read too much into it,” a principal and portfolio manager at GNI Capital Inc., said Charles Norton, said, referring to yesterday’s rally. “You’d like to see it be led by the market leaders, not the sort of stuff bouncing off the bottom that’s been beaten up,” he said referring to financial stocks and regional banks.

The Dow soared 286.87, or 2.18%, to 13,468.78. The blue chips closed near their highs after zigzagging throughout much of the session. On Friday, the Dow fell 281 points.

Broader stock indicators also rebounded. The S&P 500 index rose 34.61, or 2.42%, to 1,467.67. The Nasdaq composite index rose 36.08, or 1.44%, to 2,547.33.

The rally was not as widespread as the rise in the major indexes suggested, though. Advancing issues outnumbered decliners by about 6-to-5 on the New York Stock Exchange, where consolidated volume came to a very heavy 5.09 billion shares, compared with 4.54 billion shares traded Friday. Mr. Norton noted that the session’s volume had been about 20% to 25% ahead of that of Friday’s in the early going but volume ended up only 8.5% ahead of Friday by the close. He noted that investors typically like to see volume accelerate through the day in a rising market, as such moves can suggest widespread confidence in the advance.

“I think a lot of it has to do with people sort of squaring up before the Fed on the short side,” Mr. Norton said, referring to the market’s move higher and investors who sell stocks “short,” betting that they will fall. Such investors can be forced to buy stock to cover their positions if they believe the market is poised to move higher. Falling oil also gave a boost to stocks. Light, sweet crude futures tumbled $3.42 to $72.06 a barrel on the New York Mercantile Exchange. Gold prices fell, while the dollar moved in a mixed range against other major currencies.

Stocks have endured a volatile couple of weeks as troubles in the global credit markets — rooted in the rise of subprime loan defaults in America — have unfolded. Some investors are concerned that bad subprime loans, those made to borrowers with poor credit, remain on the books of some financial companies and have yet to be disclosed.

A co-head of portfolio strategy at Lehman Brothers Investment Management, Aaron Gurwitz, said that while he would be surprised if the Fed were to adjust short-term interest rates, the central bank could indicate it stands ready to provide liquidity should credit markets seize up. He noted, however, that the repricing of credit that’s occurring in the markets isn’t something the Fed would likely want to stand in the way of. “I think it’s a short-term problem,” he said. “I think that the uncertainty in the credit markets, the worries about a liquidity crisis that has to be dealt with, is a risk to the financial markets — but I think it’s a long way from being a risk to the macro economy or the ability of most companies to make money.”