US stocks rebounded Wednesday after Joe Biden racked up several surprise Democratic primary wins, keeping up a streak of volatility that’s likely to continue after last week’s massive rout.

The Dow Jones industrial average spiked as much as 857.99 points, or 3.3 percent, in early trading, signaling a recovery from the shock of the Federal Reserve’s surprise interest rate cut on Tuesday. The S&P 500 and Nasdaq composite rose as much as 3 and 2.8 percent, respectively.

As the market tried to bounce back from last week’s panic over the coronavirus epidemic, observers said, traders appeared encouraged by Biden’s Super Tuesday surge to the front of the Democratic presidential race ahead of Sen. Bernie Sanders, who has pledged to impose a wealth tax and create a single-payer health care system.

“Worst case, if the economy really, really deteriorated and Sanders was the frontrunner, he would be much more difficult from a capital markets perspective,” said Eric Marshall, director of research at Hodges Capital. “And the fact that that risk has been taken of the table to some degree (led to) a relief rally.”

Health care stocks led the rally as the prospects of Sanders’ “Medicare for All” proposal dimmed, with shares in insurance giant Anthem surging as much as 15.7 percent.

UnitedHealth shares jumped as much as 13.1 percent and led the Dow companies, while CVS shares climbed as much as about 7.1 percent.

Biden’s success looked like a boon to managed-care companies such as Cigna and Humana, which had been feeling pain from the coronavirus outbreak and Sanders’s stint as the Democratic frontrunner, according to Sahak Manuelian, managing director and head of equity trading at Wedbush Securities.

“The fundamental backdrop for these companies had been really strong and then you had coronavirus and you had Bernie Sanders really leading in the polls and these things just came apart,” Manuelian said.

But traders may just be using Biden’s surge as an excuse to buy health stocks in a turbulent market, said Jim Paulsen, chief investment strategist at the Leuthold Group.

“It’s very hard to write a story that there’s been this big shift in politics as of last night for investors looking to buy and hold health care stocks,” Paulsen said.

Stock markets have been volatile amid fears about the coronavirus spreading further outside China. The Dow plunged 786 points Tuesday as the Fed’s first emergency rate cut since 2008 failed to quell traders’ fears about economic damage from the coronavirus outbreak, which has killed about 3,200 people and sickened more than 93,000.

But that drop came after the Dow gained nearly 1,300 points Monday, its biggest single-day point gain ever, after shedding more than 3,500 points in Wall Street’s worst week since 2008.

Such big swings will likely continue in the near term in the wake of last week’s crash that sent US markets into correction territory, analysts said.

“People’s emotions are elevated,” Paulsen said. “This is what a market does after you have such an emotional collapse.”