Updated from 4:08 p.m. EDT

Stocks collapsed Wednesday, as a strong earnings season has seemingly lost its power to consistently distract investors from concerns about global demand and the inflationary effects of a growing U.S. economy.

The Nasdaq Composite led declines, once again plunging below the 2000 mark. It closed down 42.99 points, or 2.12%, to 1989.54 -- its biggest one-day decline since March 15.

Losses spread across the tech sector, with the GSTI Software Index closing down 2.6%, the Amex Network Index falling 2.8% and the Amex Biotech Index down 3.4%.

The Dow Jones Industrial Average shed 135.56 points, or 1.29%, to 10,342.60, and the S&P 500 was down 15.74 points, or 1.38%, to 1122.41. The 10-year Treasury bond traded down 25/32 in price to yield 4.49%, while the dollar was higher against the euro and the yen.

In high-volume action, more than 1.8 billion shares traded on the New York Stock Exchange, and decliners outnumbered advancers by about 7 to 2. On the Nasdaq, more than 2 billion shares changed hands, and advancers outnumbered decliners by about 4 to 1.

Both the Dow and Nasdaq fell below their 50-day simple moving averages Wednesday. A recent bounce to bring the indices near those levels in the middle of the trading day was turned away, and stocks subsequently drifted lower.

However, all major indices merely fell to levels seen just last week, as range-bound trading continues. (Since March 30, the Nasdaq has moved to close above or below the 2000 mark eight times.)

For the year, the Dow is down 0.1%, the Nasdaq is down 0.7%, and the S&P is up 0.9%.

Precious metals futures showed weakness after People's Bank of China Vice Governor Wu Xiaoling said growth in the largest copper-consuming country will slow to less than 8% this year from a six-year high of 9.1% in 2003, according to Bloomberg. Copper futures were down 5%, while silver prices lost 5.9% and the CBOE Gold Index was losing 7.3%.