Billionaire investor Carl Icahn said Friday he's stepping down as a special adviser to President Donald Trump on regulatory-reform issues. Icahn said in a letter he and the president agreed that he would cease the role. He wrote that he didn't want "partisan bickering about my role" to cloud the administration or the work of Neomi Rao, who has been appointed Trump's regulatory czar. Icahn didn't mention Trump's reaction to the violence at a white-supremacist rally in Charlottesville, Va., but his resignation comes after several executives abandoned White House business councils after Trump said "both sides" were to blame.