U.S. markets plunged deep in the red Friday morning, March 27, interrupting a stellar three-day run and offering a stinging reminder that the government's $2.2 trillion rescue package won't blunt investor anxiety just yet.

Stocks soared this week as the landmark stimulus package came into sharper view. The Senate passed the sprawling bill late Wednesday. The House is now aiming to expedite its own vote on Friday, even while one GOP lawmaker could cause a delay.

But as lawmakers scramble to get the legislation to President Donald Trump, the pandemic's toll continues to multiply. The United States now has the most confirmed cases in the world and has surpassed 1,000 deaths. A record 3.3 million Americans applied for unemployment benefits last week, according to the Labor Department, and economists say more than 40 million Americans could lose their jobs by mid-April.

The Dow Jones industrial average sank 800 points, or 3.55%, at Friday's open. The Standard & Poor's and Nasdaq also posted sharp losses of 3.18 and 2.85%, respectively.

Analysts caution that stocks are far from recovery and that investors should prepare for significant drops even lower than markets have recently seen.

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"Don't be too quick to uncork the champagne," said Sam Stovall of CFRA Research in a note Friday morning. "Friday's futures imply that investors are looking to take some profits ahead of a traditional 'retest' of the recent lows."

Thursday's rally led to the Dow to close up 1,352 points, or 6.4% - capping its second-best three-day run in history. With Thursday's close, the blue chip index had climbed 21.3% since Monday. Much of those gains were powered by Boeing, which has seen its stock price soar on the expectation of billions of dollars in government relief.

Markets across Europe slid, too. Britain's FTSE 100 dropped 5.69 percent as Prime Minister Boris Johnson said he tested positive for coronavirus and is self-isolating. Germany's DAX fell 3.8%, and the benchmark Stoxx 600 shed 3.77%.

Asian stocks were on the upswing. Japan's Nikkei 225 ended the day with gains of 3.88%. Hong Kong's Hang Seng ticked up 0.56%, and the Shanghai composite 0.26%.

With an economic stimulus bill on the way, "attention will turn back to the health crisis," wrote Wayne Wicker, chief investment officer of Vantagepoint Investment Advisers, in a note Thursday afternoon.

"More bad headlines are coming, more people's health will be negatively impacted, which will negatively affect investor psychology," Wicker wrote. "That will provide opportunities to get back in the market if you feel you've missed it."

This article was written by Rachel Siegel and Thomas Heath, reporters for The Washington Post.

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