New York - US stocks tumbled early on Friday, following global markets downward after a big drop in Chinese equities and another fall in oil prices.
About 40 minutes into trade, the Dow Jones Industrial Average stood at 15 985.99, down 393.06 points (2.40%).
The broad-based S&P 500 fell 44.43 (2.31%) to 1 877.41, while the tech-rich Nasdaq Composite Index dropped 128.68 (2.79%) to 4 486.33.
Sentiment was dented by the 3.6% loss in Shanghai stocks, the Chinese market entering official bear territory - a 20% fall from a recent high.
Adding to the woes were a fresh 12-year low in oil prices and US data that showed US retail sales fell 0.1% in December to cap the slowest year of growth since 2009.
Citigroup slumped 5.0 percent as worries about the bank's exposure to the oil market offset a big jump in earnings to $3.3bn due to lower costs. Citigroup set aside in the fourth quarter $250m in reserves for its energy portfolio, which has suffered due to low oil prices.
Wells Fargo dropped 2.9% as it also cited troubled energy loans and reported a drop in net interest margins. Earnings were flat at $5.7bn.
Dow member Intel plummeted 8.3% after reporting fourth-quarter earnings of $11.4bn, down about 2.6% from the year-ago period. Analysts cited worries about declining personal computer sales and weaker-than-expected growth in data center results.
Technology companies were generally lower, with Apple falling 2.6%, Microsoft 3.1% and Facebook 2.9%.
Petroleum-linked shares were another weak sector. ExxonMobil lost 2.8%, Apache 5.1% and Transocean 7.9%.
US-traded Chinese companies fell. Alibaba lost 3.7%, Baidu 6.5% and JD.com 4%.
Dow member Disney fell 3.6% following a downgrade by Barclays due to worries about sports network ESPN's prospects.