On Feb. 19, U.S. stocks closed at a record, led by four tech companies that were each worth comfortably over $1 trillion at the time.

What a difference a month makes.

As of the close of trading on March 19, those four companies — Apple, Microsoft, Amazon and Alphabet — along with Facebook have lost a combined $1.3 trillion in value since the market peaked. The broader S&P 500, even after gaining 0.5% on Thursday, has plunged by 29% in the past month, as the spread of the COVID-19 coronavirus threatens to send the global economy into a tailspin.

The Seattle area, home to Microsoft and Amazon, and the San Francisco-Silicon Valley corridor, where Apple, Alphabet and Facebook are based, have been two of the hardest-hit areas in the nation in terms of COVID-19 outbreaks. In San Francisco and surrounding counties, residents have been ordered to shelter in place since Tuesday, while schools and businesses across Seattle have closed.

Investors are selling off just about anything and everything in the stock market, with some analysts indicating that a recession is already here.

Hedge fund manager Bill Ackman of Pershing Capital predicted on Wednesday that "hell is coming," and urged President Trump to shut down the country for 30 days. Tech stocks led the 11-year bull market coming out of the financial crisis and many are now firmly in bear market territory.

Initially, as the coronavirus emerged in China and threatened the supply chains of companies dependent on Chinese manufacturing, hardware providers warned of at least a temporary slowdown. Apple said in mid-February that iPhone supply issues and reduced Chinese demand would hurt quarterly results. In late February, Microsoft said it would miss quarterly guidance, because its "supply chain is returning to normal operations at a slower pace than anticipated"

But with businesses in some of the biggest U.S. markets being forced to shutter and unemployment expected to spike, the COVID-19 crisis is headed straight for consumers' wallets. Apple said over the weekend that it will close all of its stores outside of Greater China until March 27. Michael Walkley, an analyst at Canaccord Genuity, on Thursday cut his stock price target on Apple to $300 from $345.