A Gary Cohn resignation would 'crash the markets'

Gary Cohn At Regional Media Day

Investors are counting on Trump aide Gary Cohn to help push through tax reform, Jeffrey Sonnenfeld tells CNBC.

The markets would crash if top White House economic adviser Gary Cohn resigns, Yale School of Management's Jeffrey Sonnenfeld told CNBC on Thursday.

"I don't want to be an alarmist, but there is a lot of faith that he is going to help carry through the tax reform that people are looking for," Sonnenfeld said on " Squawk Box ."

"I think if he steps away, it would crash the markets."

The New York Times reported Wednesday that Cohn, who is Jewish, was "upset" and "disgusted" with President Donald Trump 's response to violence in Charlottesville, Virginia.

During a heated press conference Tuesday, Trump defended his comments that "both sides" were to blame for the violent white nationalist rally in Virginia that left a counterprotester dead. The extreme right protesters shouted anti-Semitic slogans as they marched through Charlottesville.

That prompted several members of Trump's advisory councils to announce their resignations, which caused Trump to eventually dissolve the councils entirely.

"A number of people" on Wall Street and at Cohn's former firm Goldman Sachs have called him to suggest that he resign from the administration, said "Squawk Box" co-host Andrew Ross Sorkin, who also writes for the Times.

Some analysts suggest that the promise of tax reform and other pro-business legislation by Trump is partly responsible for the stock market's rise since the election. A Cohn resignation could be a hit to Trump's plans to revamp the tax code.

The White House did not immediately respond to a CNBC request for comment Thursday.

In a note to clients on Thursday, BMO Capital Markets said the markets have turned their focus to Cohn and his commitment to the administration. The firm said it is reluctant to make too much out of media chatter "other than simply a nod to the risk as the market enters a relatively quiet period."

Earlier this year, several news outlets speculated that Cohn would be the leading candidate to replace Federal Reserve Chair Janet Yellen once her term ends in February.

Before joining the Trump administration, Cohn was the No. 2 executive Goldman.

Sonnenfeld also spoke on the decisions for CEOs to abandon Trump's councils. He said if JPMorgan Chase CEO Jamie Dimon had spoken out sooner other leaders would have followed suit much faster.

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