The Dow Jones industrial average rose as much as 349.75 points, or 1.5 percent, as hopes about the pandemic peaking persisted on Wall Street. The S&P 500 and Nasdaq composite also climbed as much as 1.3 and 1.4 percent, respectively, after closing Tuesday in the red.

Investors held onto optimism as Dr. Anthony Fauci, the Trump administration’s top infectious disease expert, said the US may be able to reopen schools by the fall as officials work to contain the crisis. But experts warn that the market could tumble again as coronavirus deaths climb further.

“If it seems like we’re out of the woods, it’s only because we’re like Goldilocks and we’ve just gone into the bears’ cabin,” said Nancy Davis, chief investment officer at Quadratic Capital. “Now we find out if all the policy measures are too much, too little or just right.”

All three Wall Street indexes gave up big gains Tuesday as investors grappled with the growth of the pandemic as well as a drop in oil prices. The dip came as the US reported more than 1,800 new coronavirus deaths, the largest one-day total so far. New York, the national epicenter of the crisis, also reported a new daily record of 731 deaths after two days of a roughly flat body count.

While Gov. Andrew Cuomo said deaths are a “lagging indicator” of where the crisis stands, there are concerns that New York City is underestimating the death toll because many possible victims have died at home without being tested for the virus.

“While we know economic data is missing or poor quality, if the COVID-19 data proves to be unreliable then we’ll be in a world of hurt, afloat in a sea of red on a rudderless ship — especially with investors trading on sentiment rather than the economics for now,” Stephen Innes, chief global market strategist at AxiTrader, said in a commentary.