"The bottoming process is in hand," said Larry Wachtel, market analyst at Prudential Securities, of the market's two-week gains.

The Dow Jones industrial average closed down 40.08, or 0.5 percent, at 8,778.06, according to preliminary calculations. The Dow's loss was attributable largely to profit taking following its two-day gain of 335.75.

Broader market indexes finished mixed. The Nasdaq composite index rose 16.00, or 1.2 percent, to 1,361.01, having advanced 75.73 in the previous two sessions. The Standard & Poor's 500 index fell 1.48, or 0.2 percent, to 928.77, following a two-day gain of 46.04.

The market's three major gauges claimed their second straight weekly advance, a feat they last accomplished the weeks that ended March 1 and March 8. For the week, the Dow gained 0.4 percent, the Nasdaq surged 4.2 percent and the S&P advanced 2.2 percent.

Market observers attributed the two-week gains to signs that the market found a bottom in late July. The advance also reflected investors' relief that most of the nation's biggest companies were able to comply with a government deadline Wednesday to certify their financial results.