Billionaire investor Carl Icahn is expected to be named special adviser to the president on overhauling federal regulations, according to people familiar with the matter.

The position isn't an official government job; Mr. Icahn won't get paid and won't have to give up his current business dealings. Yet it is the latest example of a quintessential outsider assuming power as President-elect Donald Trump assembles his cabinet secretaries and advisers.

Mr. Icahn already has been wielding influence in Mr. Trump's transition team. He is playing a central role in selecting the next chairman of the Securities and Exchange Commission, the people familiar with the matter said.

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