Stocks started the day higher as it appeared markets were shrugging off the coronavirus news, but took a turn for the worse after a second case was confirmed on US soil in Illinois. The first case was confirmed on Tuesday in Washington state. Both patients had traveled to the central Chinese city of Wuhan, where the virus outbreak originated.
Multiple cities in Wuhan's Hubei province are facing travel restrictions ahead of this weekend's Lunar New Year celebrations. Investors are now beginning to worry about the outbreak's impact on the Chinese economy, which is widely considered the growth engine of the global economy.
Still, it was the worst week for the Dow since mid-August.