Updated from 4:09 p.m.Stocks ended the month with a bang as optimism grew that the economy might be about to turn the corner. The Dow Jones Industrial Average jumped 139 points, or 1.6%, to 8850.26. The Nasdaq rose almost 21 points, or 1.3%, to 1595.91 and the S&P 500 climbed almost 14 points, or 1.5%, to 963.59. For the month, the Dow added over 4%, the Nasdaq gained almost 9% and the S&P climbed 5%. Treasuries fell, with the yield on the 10-year note at 3.36%. Crude oil prices were sharply higher at $26.35 in London. The dollar was weaker against the euro, but slightly stronger against the yen. The Dow reached its highest level since early December of last year, while the Nasdaq broke above the peak reached on June 5, 2002. The S&P also closed at an 11-month high. This was the fourth straight monthly rise for the Nasdaq, the longest string since 1999, while the S&P had its third consecutive month of gains. But some still voiced skepticism. "There is life in the economy yet, but we still have a challenging environment, employment data is still poor," said Ron Hill, market strategist at Brown Brothers Harriman & Co. "Either people really confident or they are chasing the biggest bang for the buck. If those fundamentals don't come around, can this really lead you on a sustained rally?" Despite it being a Friday, investors actively participated in the market once again, with volume totaling 1.7 billion on the New York Stock Exchange, and advancers were ahead of decliners by more than 3 to 1. At the Nasdaq, 2.2 billion shares traded hands, while market breadth topped the 2-to-1 margin. "They liked today's economic numbers a lot. The improvement in the equities market is an indication of growing confidence the economy will come out of the doldrums," said Lyle Gramely, senior economic advisor at Schwab Capital Markets. "But whether this is enough of a motivating factor, it's hard to say." An improving manufacturing picture was helped buoy the market. The Chicago Purchasing Management Index unexpectedly rose to 52.2 in April. Any number above 50 indicates business is improving. Investors also got the University of Michigan's April revision of its consumer confidence index, which showed buyers were more optimistic in May than in April. The figure rose to 92.1, from 86 in April, but was still below expectations of a 93 reading. Personal spending unexpectedly fell 0.1% in April, compared to a gain of 0.8% the previous month, while personal income was unchanged from a 0.4% rise in March, the Commerce Department said. "The data was mildly encouraging and could indicate we're off to the races," said Gramely at Schwab Capital Markets. "But it's still too early to jump to that conclusion. I'd like to see more hard evidence the economy is really coming out of the doldrums." To top off the good mood, markets got news of the U.S. terror alert being lowered to yellow, or elevated, from orange.