STOCKS FALL over worries of economic effects of virus outbreak.

U.S. stocks fell sharply Friday as fears spread through the markets that the virus outbreak emanating from China will dent global growth.

The Dow Jones Industrial Average skidded more than 600 points and the S&P 500 index erased its gains for January.

Technology companies, which do a lot of business with China, led the losses. Airlines fell after Delta and American suspended flights to and from the country.

The S&P sank 58.14 points, or 1.8%, to 3,225.52. The Dow fell 603.41 points, or 2.1%, to 28,256.03 The Nasdaq dropped 148 points, or 1.6%, to 9,150.94.

Bond prices rose, a signal that investors are seeking safety. The yield on the 10-year Treasury fell to 1.51% from 1.55% late Thursday.

Just two weeks ago, the S&P 500 had closed at an alltime high, having climbed about 13% since early October. A preliminary trade deal signed by the U.S. and China in January eased a big source of uncertainty in the markets, volatility was running at 12-month lows, and even a dust-up between the U.S. and Iran didn’t rock the markets.

Then came the virus outbreak in China.

Markets around the globe have sold-off on concerns about the potential economic impact of the outbreak. Hong Kong’s Hang Seng fell 5.9% this week and South Korea’s Kospi dropped 5.7%. Markets in Europe declined as well. The U.S. stock market, which had calmly been setting record after record, suffered its worst January since 2016 and its first monthly loss since August.

China’s stock markets will reopen Monday after being

closed since Jan. 23 for the Lunar New Year. A lot of pent-up selling has probably built up in the meantime.

Some funds that try to mimic the movements of Chinese indexes are still trading in the United States and elsewhere. These exchangetraded funds are moving on investors’ expectations for where Chinese stocks would be if markets in mainland China were still open.

For example, the Xtrackers Harvest CSI 300 China AShares exchange-traded fund tracks an index of large stocks that trade in Shanghai and Shenzhen. It’s down roughly 9% since Jan. 23.

The World Health Organization has declared the outbreak a global emergency, a designation that signals that the virus is now a significant risk to other countries and requires a global response.

The U.S. on Friday declared temporary travel restrictions to take effect Sunday that will bar entry into the U.S. by any foreign national who has traveled to China in the past 14 days.

“It seems like the equity market is now coming around to the realization that maybe this is something that may linger for some time,” said Sameer Samana, senior global market strategist at Wells Fargo Investment Institute.

American Airlines fell 3.2% and Delta Air Lines slipped 2.4%. Apple, which relies on Chinese consumers for sales and factories for supplies, fell 3.9%. Nvidia slid 3.8%, and other chip makers slipped.

In another sign of how much fear is in the market, the yield on the three-month Treasury rose above the 10-year yield, a relatively rare occurrence that hasn’t happened since October. Investors see such inversions as a fairly reliable warning signal of a recession within a year or so, though its track record isn’t perfect.

Concerns over the virus’s potential impact on the global economy intensified Friday after the U.S. State Department warned against travel to China and some U.S. carriers responded by suspending flights.

The move by U.S. airlines helped deepen a slide in oil prices. U.S. crude fell nearly 6% in January, a decline that coincides with a sell-off in energy stocks. The sector is down 11.2% for the year, the biggest decliner in the S&P 500. Industrial stocks, which include airlines and other transportation companies, also ended the month in the red.

Banks and energy companies also fell broadly. A sharp climb in Amazon shares helped offset losses elsewhere. The online retailer surged 7.4% after blowing past Wall Street’s fourth-quarter profit forecasts. The company said Prime membership exploded 50% since it last disclosed that figure in 2018.

Exxon Mobil slid 4.1% after the country’s biggest oil producer’s profit slid more than 5% in the fourth quarter and fell short of Wall Street forecasts. Rival Chevron fell 3.8% after it posted a quarterly loss of $6.6 billion.

Benchmark crude oil fell 58 cents to settle at $51.56 a barrel. Brent crude oil, the international standard, dropped 13 cents to close at $58.16 a barrel. Wholesale gasoline was unchanged at $1.49 per gallon. Heating oil declined 1 cent to $1.63 per gallon. Natural gas rose 1 cent to $1.84 per 1,000 cubic feet.