Stocks fell sharply on Friday, giving back some of the strong gains experienced in the previous three days to cap off another volatile week on Wall Street. Sentiment took a hit as investors focused back on the coronavirus outbreak as the U.S. became the country with the most confirmed cases. The Dow Jones Industrial Average dropped 915.39 points, or 4.1%, to 21,636.78. The S&P 500 slid 3.4% to 2,541.47 while the Nasdaq Composite closed 3.7% lower at 7,502.38. Boeing dropped 10.3% to lead the Dow lower. Chevron and Disney each fell more than 8%. Boeing fell after Treasury Secretary Steven Mnuchin said the airplane maker won't seek a government bailout. Energy and tech were the worst-performing sectors in the S&P 500 as they dropped 6.9% and 4.6%, respectively. Energy was pressured by a 4.8% drop in crude prices. Still, the major averages posted strong gains for the week. The Dow rose 12.8% week to date, its biggest one-week gain since 1938. The S&P 500 gained 10.3% this week for its best weekly performance since March 2009. The Nasdaq also had its biggest weekly gain in 11 years, rising 9.1%.

"We believe medium-term risks are skewed to the downside after this rally," Maneesh Deshpande, Barclays' chief U.S. equity strategist, said in a note on Friday. "Two other uncertainties facing investors (the length of the economic quarantine required to contain the virus and the ultimate economic damage) remain unresolved." "Bear market 'head-fake' rallies are not uncommon," Deshpande added. The bear runs that began in 2000 and 2007 both had head fakes of more than 20% before ending, Barclays data shows. The biggest bear market head fake came during the bear market that started in 1937, when stocks rallied more than 60% before falling again.