Investors are worried that after six months of rallies, stocks have climbed too high given a still- weak economic recovery.

"There is doubt ... that we have further gains this year. We are now looking for reasons to justify our worry," said Brian Pears, equity trader at Victory Capital Management in Cleveland.But he also said investors’ desire to own stocks outweighs the urge to sell.

The tech-dominated Nasdaq composite index closed down 26.50, or 1.4 percent, at 1,817.20, according to preliminary calculations. Yesterday, the Nasdaq dropped 58.02, its largest one-day point loss since July 1, 2002.

The market’s other gauges also fell, having just suffered their biggest losses in just over four months, or since May 19. The Dow Jones industrial average fell 81.55, or 0.9 percent, to 9,343.96, having dropped 150.03 yesterday. The Standard & Poor’s 500 index declined 6.12, or 0.6 percent, to 1,003.26, having shed 19.67 in the previous session.

Investors were extending yesterday’s huge sell-off, sparked by a surprising decision by OPEC to cut oil production target by 3.5 percent beginning in November. The move by the Organization of Petroleum Exporting Countries, which produces about a third of the world’s crude, set off worries that higher energy prices will hamper the economic recovery.

The Commerce Department issued disappointing economic data showing demand for durable goods dropped by a sizable 0.9 percent in August, raising doubts about the manufacturing sector’s delicate recovery. The decrease in new orders for durable goods, items including cars and home appliances expected to last at least three years, was the first and largest decline in four months and bigger than the 0.5 percent dip economists anticipated.

Manufacturers were mixed following new of the drop in durable-goods orders. Caterpillar Inc. $1.02 to $69.42, but General Motors Corp. rose 9 cents to $40.91. Both are Dow components.

In a second report, new applications for jobless benefits fell last week by a seasonally adjusted 19,000 to 381,000, a seven-month low. But at least half of the decrease was attributable to workers not being able to file claims because of Hurricane Isabel, which hit the East Coast.

Analysts said investors were nervous about placing more bets on Wall Street ahead of third-quarter earnings coming out beginning next month. But analysts said they’re optimistic about companies’ results.

"We have started to see this year a trend where companies make conservative estimates on their earnings. The don’t want to overestimate ... and in the past three quarters, earnings have exceeded expectations. I think we will continue to see that next quarter," said Thomas F. Lydon Jr., president of Global Trends Investments in Newport Beach, Calif.