As director of the National Economic Council, he is seen as the driving force behind proposed business-friendly and economically stimulative policies on taxes and infrastructure.
On Thursday, a rumor that Cohn was quitting his role spooked the market, sending stocks lower. The rumor seemed plausible after multiple reports suggested that Cohn was "upset" and "disgusted" with Trump's press conference on Tuesday addressing the violence in Charlottesville, Virginia.
"We firmly believe that if Mr. Cohn departs the White House there will be a material market sell-off as he is running point on tax reform and considered as a front-runner to replace Federal Reserve Chair Yellen," Isaac Boltansky, an analyst at Compass Point, said in a note to clients.
Here's how Cohn, who bounced around from school to school as a young boy because "no one understood how to deal with a dyslexic kid," ended up as a key player on Wall Street and in the White House:
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