Coronavirus fears slam the stock market

The big picture: As the outbreak worsens, so do concerns that it could hit the global economy right as prospects for growth were beginning to look up.

Details: The U.S. Treasury yield curve inverted on Monday and again on Friday, oil prices have fallen more than 10% in the past two weeks and the price of copper, a bellwether of economic health, went on a record 12-day losing streak.

The bottom line: Bond and commodity markets have been clearly signaling distress all week. The inverted yield curve has happened before every U.S. recession in the last 50 years and has shown a false positive only once.

• Economists at the Federal Reserve call it the "best summary measure" of economic downturn, and yields on the benchmark 10-year Treasury note have fallen by a staggering 38 basis points over the past month.
• Copper is seen as a barometer of the economy's health because of its use in homebuilding and commercial construction

Go deeper: What's happening with the coronavirus