Shares on Wall Street sank deeper on Thursday after Apple said weak sales in China had hurt its business, stoking wider concerns over trade tensions and economic slowdown.
A revenue warning from a major airline, as well as data showing declines in US car sales and manufacturing activity last month added to the gloom.
The Nasdaq plunged 3%, the Dow tumbled 2.8% and the S&P 500 fell 2.5%.
Apple was the biggest loser on the Dow, plunging almost 10%.
Delta Airlines dropped 9%, following its own warning to investors that revenues would be lower than expected for the end of 2018.
The news hit other airline stocks, including American Airlines, which dropped more than 7%.
Overall, the Dow shed more than 660 points, closing at 22,6868.2.
The Nasdaq lost 200 points to end at 6,463.5, while the S&P 500 shed 62 points to end at 2,447.9.
The declines added to the losses that have rocked markets in recent months.
Investors are trying to gauge the effects on companies of rising interest rates, trade tensions and signs of economic slowdown – especially in China, the world’s second largest economy.
Apple’s disclosure spurred sell-offs of other technology firms and companies that do a lot of business in China, including European luxury brands.
Boeing and Caterpillar, both of which are considered sensitive to trade tensions, ended the day down about 4%.
Ford and General Motors, both of which reported declines in car sales last month, were also lower, while sectors considered safer investments, such as property, gained.
The data appeared to bolster arguments for a pessimistic outlook, as did a report from the Institute for Supply Management showing US factory activity in December suffered the biggest drop since the financial crisis.
Capital Economics said the figures offered “clear evidence” that weaker growth is having an effect.
“There is a risk that the slowdown in the factory sector could mark the start of a more serious downturn in the wider economy,” analysts at the firm said.