Billionaire investor Carl Icahn targeted environmental and banking regulations on Thursday as big drags on U.S. corporate investment and said revamping them would be a priority in his role as adviser to President-elect Donald Trump.

Icahn, tapped by Trump on Wednesday as a special adviser for regulatory reform, also said in an interview on CNBC that he was surprised at criticism that his vast business dealings would pose conflicts of interest with his advisory role.

"I honestly am sort of surprised that so much is being made of my being named to that," Icahn said in the wide-ranging interview, in which he also voiced concern about U.S. stock market levels. He said he owns companies in every sector and has no specific duties outlined in his role for Trump.