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," he said.

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

The extreme right protesters were heard shouting anti-Semitic slogans as they marched through Charlottesville.

During a heated press conference Tuesday, Trump defended his comments that "both sides" were to blame for the violence over the weekend that left a counterprotester dead.

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 CNBC's Andrew Ross Sorkin, who also writes for the Times.

A White House official told CNBC on Thursday "Gary intends to remain in his position as NEC Director at the White House. Nothing's changed." The official later clarified to say, "Nothing has changed. Gary is focused on his responsibilities as NEC Director and any reports to the contrary are 100% false."

A Cohn resignation could be a hit to Trump's plans to revamp the tax code. 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.