The selloff since the start of the year continued on Wall Street on Wednesday, led by energy stocks, as crude oil prices fell to new lows and on deepening fears of slowing global growth.
The selloff was broad: All 30 Dow components were lower and all the 10 major S&P sectors were also in the red.
The beaten-down S&P energy sector's 2.27 percent fall led the declines. Chevron dropped 4.6 percent and Exxon 2.8 percent.
US crude prices sank to their lowest since 2003 and Brent held close to 12-year lows as a supply glut bumped up against bearish financial news that deepened worries over demand.
IBM fell nearly 5 percent to $121.88 and Goldman Sachs dropped 0.8 percent to $155.88 after both issued disappointing earnings reports.
Fears of a slowdown in China, the world's second-largest economy and a key market for US companies, has also weighed on equities and commodities, leading to turbulent start to the year on Wall Street.
"The focus remains on oil and the impact of low oil prices, which points to slowing growth and possibly, even stagnant to negative growth here in the United States," said Peter Cardillo, chief market economist at First Standard Financial in New York.
At 9:37 am ET (1437 GMT), the Dow Jones industrial average was down 278.17 points, or 1.74 percent, at 15,737.85.
The S&P 500 was down 29.41 points, or 1.56 percent, at 1,851.92 and the Nasdaq Composite index was down 67.53 points, or 1.51 percent, at 4,409.42.
The S&P 500 has fallen 8 percent so far this year, losing more than $1.4 trillion in value, according to Thomson Reuters data. The small-cap Russell's 2000 index has fallen about 23 percent from its June highs, moving into bear market turf.
"I don't think that the rest of the market is headed for a bear market, but certainly there's a bear grip that could take us down another 3-4 percent in the S&P 500," Cardillo said.
US corporate earnings are unlikely to offer relief: S&P 500 earnings on average are expected to fall 4.4 percent, according to Thomson Reuters data.
Bellwethers Apple, Amazon, Facebook , Alphabet and Microsoft were down between 1.5 percent and 4 percent.
Netflix was also swept up by the downbeat sentiment, dropping 5 percent to $102.57, despite reporting a better-than-expected growth in its subscriber base.
Declining issues outnumbered advancing ones on the NYSE by 2,613 to 230. On the Nasdaq, 2,097 issues fell and 259 advanced.
The S&P 500 index showed no new 52-week highs and 122 new lows, while the Nasdaq recorded three new highs and 317 lows.