Investment guru Jeffrey Gundlach blames presidential hopeful Senator Bernie Sanders for the market’s tumultuous rout this week.

“If this stock market reversal is due exclusively to the virus, then why is United Healthcare down far more than SPX? Why is healthcare as a sector broadly not outperforming? Answer to these questions: the market is digesting a better than 50% chance of Bernie getting the nomination,” Gundlach wrote in an email to CNBC’s Scott Wapner on Wednesday.

“Maybe this is the dark side of momentum investing (which is exactly what defines “passive”),” Gundlach wrote.

“The market goes down in a knee jerk way on the Bernie rise, but the market going down makes Bernie’s polls go up on his rejection of a market based economy. Which makes the market go down another leg. Rinse and repeat,” the DoubleLine Capital CEO and Wall Street “Bond King” wrote.

At Tuesday night's debate, Sanders ridiculed President Donald Trump as a “self-described great genius” who’s proclaimed that April is the “magical” time that the coronavirus will be wiped out.

U.S. stocks turned lower in afternoon trading on Wednesday in a fresh wave of selling sparked by fears of the coronavirus spreading in the United States.

The main indexes have declined in the past four sessions and the Dow shed more than 1,900 points in the last two days on fears of a pandemic. The S&P 500 is still about 7% off its all-time high it hit last Wednesday.

The U.S. Food and Drug Administration officials warned the outbreak was on path to becoming pandemic, according to a report. Germany is at the beginning of an epidemic after new cases sprung up which can no longer be traced to the virus's original source in China, its health minister said.

"The selloff isn't driven by fundamentals, it is driven by fear," said John Ham, associate advisor at New England Investment and Retirement Group. "At the end of the day, it is a buying opportunity for investors with a long-term focus."

Earlier in the day, U.S. Centers for Disease Control and Prevention urged Americans to prepare for the virus to spread in the United States. President Donald Trump is scheduled to hold a news conference on the coronavirus at 6 p.m. ET 

Meanwhile, the other Democratic presidential candidates also tore into Trump’s response to the coronavirus epidemic, saying in their debate Tuesday that a failure to take action has fed public fear and this week’s plunge in stock markets, Bloomberg News reported.

“The stock market’s falling apart because people are really worried -- and they should be,” former New York Mayor Michael Bloomberg said when asked about the coronavirus during the debate in Charleston, South Carolina. “We don’t have anybody to respond.”

(Bloomberg is the founder and majority owner of Bloomberg LP, the parent company of Bloomberg News.)

Biden, citing his experience handling the Ebola outbreak in the Obama administration, said he would increase funding for federal health agencies, attacking Trump for seeking to cut back.

“I was part of making sure that pandemic did not get to the United States, saved millions of lives,” Biden said of Ebola.

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