U.S. and global stock markets soared Monday as investors took in overseas progress against the coronavirus, even as Americans have been warned that the coming week will be the "hardest and saddest" of the outbreak as infections near their peak.

South Korea is recording encouragingly low numbers of new cases, and China's powerful economy is beginning to come back online. But U.S. losses are mounting, with deaths surpassing 9,500 over the weekend. There's been an unprecedented flood of jobless claims - nearly 10 million in the past two weeks - and the White House has predicted as many as 240,000 U.S. deaths. President Donald Trump insists "we're starting to see light at the end of the tunnel."

The Dow jumped more than 900 points, or 4%, at the open. The Standard & Poor's 500 and Nasdaq also posted big gains.

"Stocks in the UK, Europe and Asia rallied on Monday as investors became more optimistic about life getting back to normal later this year," Russ Mould, investment director at AJ Bell, wrote in commentary. "Signs that coronavirus may be peaking in parts of mainland Europe have given some hope that the economic hit will be short-lived."

Japan's Nikkei 225 climbed more than 4.2% even with the nation expected to announce a state of emergency due to the virus and Hong Kong's Hang Seng closing up 2.2%. European markets were up across the board, with the benchmark Stoxx 600 index up nearly 3% in midday trading. Britain's FTSE 100 rose more than 2% despite Prime Minister Boris Johnson's hospitalization from the novel coronavirus.

But the economic devastation in the U.S. continues to grow, as the virus birthed a recession that has already seen unemployment offices overwhelmed by record jobless claims that span most American industries. The Wall Street Journal estimates more than one-quarter of the U.S. economy has been idled by the pandemic.

"A virus that shut down the economy causing a recession is unprecedented in modern history," Nancy Tengler, chief investment officer of Laffer Tengler investments, wrote in commentary. "The rapidity of the decline reminds of 1987. The potential for recession reminds many of 2008-2009. Still, it is too soon to tell."

Businesses and households await massive waves of government stimulus, which has already equaled 10% of U.S. gross domestic product. Small-business owners have reported major delays in getting approved for loans without which many will close their doors. Officials at the Internal Revenue Service have warned that $1,200 relief checks may not reach many Americans until August or September if they haven't already given their direct-deposit information to the government.

Oil fell as investors looked toward an emergency summit to address the ballooning global oil supply, another consequence of the pandemic. Brent crude, the global oil benchmark, declined more than 2.3% to trade at $33.30 a barrel. Tensions between Russia and Saudi Arabia have strained discussions about production cuts as demand weakens.

Ten-year U.S. Treasury yields rose slightly in early trading to .05, suggesting investor confidence is on the rise. Yields rise when prices drop, as investors move toward riskier ground. But gold, another safe-haven, was also trading up 1.5%. to $25.20 per ounce.

The full scope of the economy's losses will be clearer after the upcoming wave of first-quarter earnings reports. 64% of the S&P 500′s sectors are projected be in the red, according to commentary from Sam Stovall of CFRA Research, while airlines, copper, department stores, and leisure products are projected to post greater than 100% declines in earnings per share.

"Investors are advised to fasten their safety belts," Stovall wrote, "because it's likely to be a bumpy quarter."