Global stock markets plunge

The Dow Jones Industrial Average had its largest single-day drop in history on Thursday. Fears about the effect of the coronavirus outbreak on businesses have pulled the rug out from under global markets, which were performing better than ever before the disease began to spread. The S&P 500 index is down 12 percent from its all-time high a week ago, and stock markets in China, India, Japan, and South Korea are falling, as well.

How bad is it? Some economic experts said the setbacks represent an overdue market correction, though this one hit faster and harder than expected. U.S. markets survived a correction as recently as 2018. If stock values drop by more than 20 percent, it could signal a recession.

Dig deeper: Read my obituary of Paul Volcker, the 1980s Federal Reserve chairman who showed future generations how to keep the economy stable.