Coronavirus, Oil Price Drop Spark Stock Market's Worst Day Since 2008

Amid the worst day for U.S. stocks since the 2008 financial crisis, the five most valuable tech companies lost $321.6 billion in value, with Apple accounting for almost one-third of that sum.

Shares of the iPhone maker plunged 7.9%. Microsoft, Facebook and Alphabet each lost more than 6% and Amazon fell 5.3%. They had been among the biggest contributors to the market’s extended rally that lifted the S&P 500 to a record just last month, and now their declines are having an outsized impact on the broader index.

Monday’s market...

Investors look at a number of signals to forecast if the economy is headed for a recession. And those signals are now flashing bright red.

The clearest signal is coming from the stock market. The Dow dropped 1,800 points in early trading Monday — a 7% decline on top of the nearly 12% decline since it hit a record high on February 19. The latest slump put the Dow close to "bear market" territory, or when stocks sink at least 20% from their previous peak.

Just a few weeks ago,...