By STAN CHOE

NEW YORK (AP) — Fear swept back through the stock market on Thursday as worries about the viral outbreak in China knocked the S&P 500 off its record high and had it on pace for its worst day this month.

Stocks had started the day off higher following another round of stronger-than-expected reports on the U.S. economy, but the market slumped suddenly in the late morning. The S&P 500 was down as much as 1.3% at one point, Treasury yields fell and the price of gold rose, before the moves moderated in the afternoon.

Market watchers said they didn’t see one clear trigger for the movements, which reminded them of the market’s sudden shifts during the height of the U.S.-China trade war, when stocks would swing sharply following tweets from President Donald Trump.

“You have this push and pull between good U.S. economic data and coronavirus fears,” said Brent Schutte, chief investment strategist at Northwestern Mutual. “You’re playing that back and forth, almost as you were during the trade war, where people were reacting to changes minute by minute.”

Stocks had been pushing higher for weeks, as investors increasingly believed that stimulus and other efforts by central banks and governments around the world could limit the economic pain created by the virus. China’s central bank on Thursday cut its one-year loan prime rate to 4.05% from 4.15%.

But critics said stocks may have run too high, too fast given how uncertain the full impact of COVID-19 will be on the global economy. South Korea’s fourth-largest city, far from the center of the viral outbreak in China, urged residents to stay inside. The worry is that the number of new cases, which has been falling, could re-accelerate.

“Until we get a more definitive sign that the top is in, you’re going to have volatility back and forth and trades off coronavirus headlines,” Schutte said.

KEEPING SCORE: The S&P 500 was down 0.6%, as of 2 p.m. Eastern time, following a roller-coaster day. The index was up 0.1% in the late morning before its sudden shift downward, bottoming out around 11:30 a.m. down 1.3%.

The Dow Jones Industrial Average fell 172 points, or 0.6%, to 29,170, and the Nasdaq was down 1%.

SEEKING SAFETY: In a sign of increased caution in the market, prices for U.S. Treasury bonds jumped. Bond yields fall when their prices rise, and the yield on the 10-year Treasury sank to 1.52% from 1.57% late Wednesday.

The price of gold also rose, up $8.50 to $1,620.30 per ounce. It touched its highest price since early 2013.

VIRAL IMPACT: Besides the toll on human lives, investors worry about how much economic damage the virus will create. It’s already led to sharp drop-offs in manufacturing, travel and other economic activity in China, and the fear is how long that will last and how far it will spread in the interconnected global economy.

The world’s largest shipping company, Denmark’s A.P. Moller Maersk, said Thursday it expects a weak start to the year due to the virus. Air France, meanwhile, said that COVID-19 could mean a hit of up to 200 million euros, or $220 million, for its operating results from February to April.

ENCOURAGING ECONOMIC SIGNS: A survey of manufacturers in the mid-Atlantic region by the Federal Reserve Bank of Philadelphia jumped to its highest level since February 2017. It was much stronger than economists expected.

Another report showed that leading economic indicators in the United States rose more in January than economists forecast.

Thursday’s reports follow other data points this month showing stronger housing-construction activity and jobs growth than markets expected.

MARKETS ABROAD: European markets were lower, with Germany’s DAX losing 0.9% and France’s CAC 40 down 0.8%. The FTSE 100 in London dipped 0.3%.

In South Korea, where authorities reported the country’s first COVID-19 fatality, the Kospi sank 0.7%. Japan’s Nikkei 225 rose 0.3%, the Hang Seng dipped 0.2% and stocks in Shanghai jumped 1.8%.

RICH CRUST: Domino’s Pizza jumped24.6% after the company delivered better-than-expected fourth-quarter profit and surprisingly good sales. The company handily beat a key sales measure as it faces increasing competition from food delivery companies like DoorDash. .

BIG DEAL: E-Trade surged23.3%after Morgan Stanley said it will buy the online brokerage firm for $13 billion, one of the biggest deals on Wall Street since the financial crisis. Morgan Stanley fell3.9%. The deal comes less than a year after a vicious fight for customers resulted in discount brokers like E-Trade slashing or eliminating fees. Rival Charles Schwab is in the process of buying TD Ameritrade.

EARNINGS: Investors continued digesting a steady flow of corporate earnings. Zillow Group jumped17.4%and Avis Budget Group also soared13.5%after reporting solid financial results. Online postage provider Stamps.com surged61.5%after blowing away analysts’ forecasts. ViacomCBS fell17.3%and Boston Beer slid8.3%after reporting disappointing results.

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By MARI YAMAGUCHI and FOSTER KLUG

YOKOHAMA, Japan (AP) — About 500 passengers left the cruise ship Diamond Princess on Wednesday at the end of a much-criticized two-week quarantine aboard the vessel, docked in Japan, that failed to stop the spread of the new virus among passengers and crew.

The quarantine’s flop was underlined as authorities announced 79 more cases, bringing the total on the ship to 621. Results were still pending for some other passengers and crew among the original 3,711 people on board.

Japan’s government has been questioned over its decision to keep people on the ship, which some experts have called a perfect virus incubator. The Diamond Princess is the site of the most infections outside of China, where the illness named COVID-19 emerged late last year.

Many foreign governments say they won’t let passengers from the ship return unless they go through another quarantine period, so it was striking to see passengers disembark, get into taxis and disappear into Yokohama, where the ship is docked.

Japanese soldiers helped escort some passengers, including an elderly man in a wheelchair who wore a mask and held a cane. Some passengers got on buses to be transported to train stations. Some people still in their cabins waved farewell from their balconies to those who had already been processed.

“I’m a bit concerned if I’m OK to get off the ship, but it was getting very difficult physically,” a 77-year-old man from Saitama, near Tokyo, who got off with his wife, told Kyodo News. “For now, we just want to celebrate.”

Health Minister Katsunobu Kato said initially on Wednesday that those disembarking with negative virus tests have fulfilled the Japanese quarantine requirement and are free to walk out and go home on public transportation. He said passengers were only asked to watch their health carefully for a few days and notify local health authorities if they have any symptoms or worries.

But after meeting with experts later in the day, he urged the former passengers to refrain from non-essential outings and try to stay home for about two weeks.

“COVID-19 is not 100% known, and a lot of people got infected on the Diamond Princess. Taking those factors into consideration, we believe taking extra caution will contribute to preventing the risk of future infections,” he said.

Some passengers said on Twitter they received health forms in the morning asking if they had symptoms such as a headache, fever or coughing. Passengers who tested negative and had no symptoms still had to get their body temperature checked before leaving.

Passengers were provided with a certificate stating their negative test results and completion of the quarantine.

Still, Masao Sumida, a 84-year-old passenger from Chiba, near Tokyo, told NHK television he is worried people around him may have doubts. “I know I tested negative, but I’m afraid people may try to stay away from me,” he said.

Mitsuo Kaku, a professor at Tohoku University’s Laboratory of Infectious Disease, said on NHK that the risk of virus transmission by those who tested negative is low, but passengers who get off the ship should “use ample precautions” to protect themselves and people around them for about two more weeks.

About 500 passengers who planned to disembark on Wednesday had all left the ship by evening, and Japanese officials are to spend the next three days conducting the disembarkation of about 2,000 others. The Diamond Princess was quarantined in Yokohama near Tokyo after one passenger who left the ship earlier in Hong Kong was found to have the virus.

Even though Japanese officials insist the number of infected patients is leveling off, cases on the ship continue to mount daily. On Tuesday, 88 people tested positive; a day after 99 others were found to be infected.

Crew members, who couldn’t be confined to their rooms because they were working, are expected to stay on the ship.

The National Institute of Infectious Diseases said a report released Wednesday that the crew had not been fully isolated during the quarantine period. It said the quarantine was effective in reducing transmission among passengers, and that the increase in cases toward the end was mostly among crew or passengers in shared cabins.

“It should be noted that due to the nature of the ship, individual isolation of all those aboard was not possible,” it said.

Some medical experts who assisted with the quarantine have said anti-infection measures were often sloppy on the ship. Four health workers — a quarantine official, a physician, a paramedic who took an infected passenger to a hospital and a health ministry official assigned to quarantine paperwork on the ship — became infected.

Chief Cabinet Secretary Yoshihide Suga said a more controlled health watch for the crew members is starting now because they can be spread out and kept in isolation by using vacated passenger rooms.

The ship’s operator, Princess Cruises, said in a statement Tuesday that people who tested positive recently were still on the ship as they waited for transportation to hospitals.

The safety and transport logistics for moving hundreds of people will test Japanese officials.

The United States evacuated more than 300 people over the weekend who are now in quarantine in the U.S. for another 14 days. South Korea earlier Wednesday returned seven people from the cruise ship, placing the six South Koreans and one Japanese family member into quarantine.

Other foreign passengers were to be picked up by chartered flights sent from Canada, Australia, Italy and Hong Kong.

Suga has defended Japan’s handling of the quarantine. “In the beginning, the United States expressed gratitude for the Japanese side. And there are many Americans who chose to stay on the ship,” he said.

The U.S. government said Americans who remained on board instead of returning on chartered flights cannot return home for at least two weeks after they come ashore. Other governments picking up passengers have similar policies.

U.S. officials cited the passengers’ possible exposure to the virus while on board the Diamond Princess.

Japanese health officials say the 14-day quarantine on the ship was adequate, noting that all but one of more than 500 Japanese who earlier were flown back from the center of the virus in China and initially tested negative were virus-free at the end of their 14-day quarantines.

The officials also defended the precautions taken on the ship. About 1,000 crew members were told to wear surgical masks, wash their hands, use disinfectant sprays and stop operations at restaurants, bars and other entertainment areas after Feb. 5, when the first group of 10 infections was reported and the start of the 14-day quarantine was announced.

Passengers were instructed to stay in their cabins and not walk around or contact other passengers. Those in windowless cabins could go out on the deck for about an hour each day.

Crew members continued to serve guests by delivering food, letters, towels and amenities, and entering passenger cabins for cleaning. Crew members also ate in groups in a crew mess hall.

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Yamaguchi reported from Tokyo.