NEW YORK » Wall Street joined in a worldwide cascade of despair yesterday over the financial crisis, driving the Dow Jones industrials to their biggest loss ever during a trading day. Even a big afternoon rally failed to keep the Dow from its first close below 10,000 since 2004.

The sell-off came despite the $700 billion U.S. government bailout package, which was signed into law Friday after two weeks in which traders had appeared to count on the rescue as their only hope to avoid a market meltdown.

At its worst point, the Dow was down more than 800 points, an intraday record. The stock market rallied during the final 90 minutes of the trading day, and the Dow finished down about 370 points at 9,955.50.

The average is down almost 30 percent from its all-time high of 14,164.53, set a year ago Thursday.

Speculation among traders late in the session that the market's pullback had been severe enough to force the Federal Reserve into taking other steps to soothe the markets helped stocks rebound from their lows.

“;If you can't say that we're oversold now I don't know what you say. You're at least due for a bounce if nothing else,”; said Bill Stone, chief investment strategist for PNC Wealth Management.

The global plunge in stocks was under way well before Wall Street ever woke up. In Japan, the Nikkei average lost more than 4 percent. And then the losses spread across Europe - nearly 6 percent for the FTSE-100 in Britain, 7 percent for the German DAX and more than 9 percent for France's CAC-40.

In the United States, President Bush twice made unscheduled remarks on the economy, saying in Cincinnati that the economy would be “;just fine”; but that the bailout package needed time to work.

For the day, the Dow lost 3.6 percent. The selling was broad: Little more than 200 stocks finished the day higher on the New York Stock Exchange, while about 3,000 finished lower.

At its lowest point yesterday, the Dow was down 800.06, at 9,525.32. The benchmark average dipped below 10,000 for the first time since Oct. 29, 2004, and closed there despite the afternoon rally.

The crush of selling yesterday came exactly one week after the Dow lost 778 points, its biggest closing loss in terms of points.

As an indication of how fearful investors still are, government-backed debt was in high demand. The yield on the three-month Treasury bill, which moves in the opposite direction as its price, fell to 0.49 percent from late Friday at 0.50 percent.

Broader indexes also plunged. The Standard & Poor's 500 index shed 42.34, or 3.85 percent, to 1,056.89; and the Nasdaq composite index fell 84.43, or 4.34 percent, to 1,862.96. The Russell 2000 index of smaller companies dropped 23.49, or 3.79 percent, to 595.91.

Consolidated volume on the NYSE reflected the frantic pace of the day's trading: 7.81 billion shares changed hands, up from Friday's 6.52 billion.