New York - US stocks posted their worst day since November 7 on Monday as big declines in the price of gold, oil and other commodities fed a broad selloff in equities.
Selling accelerated late in the session as reports of explosions in Boston near the finish line of the Boston Marathon added to investors' nervousness.
Commodity-related shares led stocks' losses, with gold suffering its worst two-day sell-off in 30 years following weaker-than-expected Chinese data that fueled worries about global growth. The SPDR Gold Shares ETF lost 8.8% to $131.31 on record volume.
Total trading volume was the second highest of the year, with about 8.4 billion shares changing hands on US exchanges.
Analysts said the stock market had been vulnerable to a pullback, given the sharp gains since the start of the year as well as the Dow's and the S&P 500's recent record highs.
"I don't think the market has much tolerance for bad news," said Uri Landesman, president of Platinum Partners in New York.
"There was a bad Chinese GDP number, which I think spooked people to start, and technical factors. Profit-taking started taking over. Late in the day, we were getting hit by reports that there were explosions in Boston. That gets people nervous."
The Dow Jones industrial average slid 265.86 points, to 14,599.20 at the close. The Standard & Poor's 500 Index fell 36.49 points, to 1,552.36. The Nasdaq Composite Index lost 78.46 points, to close at 3,216.49.
It was the biggest daily percentage decline for all three indexes since November 7, when the market sold off following the US presidential election. The biggest declining sectors were energy and materials. The S&P energy sector index lost 3.9%. The S&P materials sector index also fell 3.9%.
Chevron, the second-largest US oil company and a Dow component, lost 2.8% to $116.57.
Shares of miner Freeport-McMoRan Copper & Gold tumbled 8.3% to $29.27.
Data showed China's annual rate of growth eased back to 7.7% from the 7.9% rate of the previous quarter and below economists' forecast for an 8.0% expansion.
Among the day's gainers, Citigroup shares edged up 0.2% to $44.87 after reporting a higher-than-expected gain of 31% in first-quarter profit.