Stocks give up early gains, end lower on Wall St.

A late-afternoon slide on Wall Street dragged stocks broadly lower Wednesday, wiping out early gains and adding to losses from a day earlier as investors worry about the economic fallout from surging coronavirus cases in the U.S.

The S&P 500 fell 1.2%. It had been up 0.3% in the early going after Pfizer and BioNTech reported updated data suggesting their potential COVID-19 vaccine may be 95% effective. The companies said they plan to ask U.S. regulators within days to allow emergency use of the vaccine.

The news, which followed encouraging data on Monday about a vaccine being developed by Moderna, initially gave investors cause for optimism that the virus-ravaged economy could begin to heal next year. But such optimism is being tempered by a spike in coronavirus cases and worries that it will lead to widespread restrictions on businesses once more.

Coronavirus counts and hospitalizations are up across the country, and health experts are warning about the possibility of a brutal winter.

“This is a market that is fluctuating as it makes a determination about the effect that the COVID-19 restrictions and lockdowns have on the reopening of the U.S. economy, versus the positive news that stems from potential vaccinations beginning in 2021,” said Quincy Krosby, chief market strategist at Prudential Financial. “It’s sort of a tug-of-war.”

The S&P 500 fell 41.74 points to 3,567.79. The Dow Jones Industrial Average dropped 344.93 points, or 1.2%, to 29,438.42. The Nasdaq composite lost 97.74 points, or 0.8%, to 11,801.60.

Small-company stocks, which have notched the biggest gains this month, gave up 22.60 points, or 1.3%, to 1,769.32.

Despite shedding modest gains from earlier in the day, stocks remain close to their record highs.