The surge in stocks — the Dow Jones industrial average added more than 140 points and the Nasdaq composite index was up nearly 2 percent — was accompanied by a spike in volume as investors returned to the market in large numbers following two days of congressional testimony from Federal Reserve chairman Alan Greenspan.

Nervousness about when the Fed will raise rates has overshadowed strong quarterly results throughout the current earnings season. Analysts say those worries may be overblown, however, as most doubt that lifting rates from their current 45-year lows would significantly dent future corporate profits.

"I don’t think we’re at the point where interest rates are going to curtail the market’s advance, but the market has to go through a digestive phase," said Steven Goldman, chief strategist at Weeden & Co. in Greenwich, Conn.

According to preliminary results, the Dow closed up 143.93, or 1.4 percent, at 10,461.20.

The broader gauges were also markedly higher:

The Nasdaq gained 37.28 or 1.9 percent, to 2,032.91. The Standard & Poor’s 500 index rose 15.86, or 1.4 percent, to 1,139.85.

Greenspan’s message to Congress — that the economic recovery is stable and the expansion will likely continue — sounded positive but carried a painful implication for the market, as many investors interpreted it as confirmation that rates will likely rise before the year is out.

For those who understood months ago that a rate hike was inevitable, the recent choppiness could have been a buying opportunity, said John Waterman, chief investment officer at Rittenhouse Asset Management. His firm repositioned itself months ago, lightening up on rate-sensitive financial stocks and cyclical names in favor of more defensive areas, such as health care.

Waterman is optimistic about the market’s momentum this year. But uncertainty over the pace of economic growth, the presidential election, fluctuations in the dollar and violence in Iraq could make for uneven trading in the weeks and months ahead.

"Days like today help to get people’s attention," Waterman said. "People are more inclined to think if they’re not in the market they should get in."

Solid results from business-to-business shipper UPS and industrial equipment specialist Caterpillar, and a jump in advertising revenue at media conglomerate Viacom all bode well for the economy.

Reports from dozens of companies, including more than 70 listed on the S&P 500 and five Dow components, made today one of the busiest days of the earnings season.