Billionaire investor activist Carl Icahn ramped up criticism of the U.S. Federal Reserve, warning about the unintended consequences of ultra low interest rates on the economy and financial markets. “They don’t understand the treacherous path they are going down,” Icahn said in an interview with Reuters, in which he also declared his support for Donald trump as a candidate to be the next U.S. president. It’s very dangerous and could be disastrous,” said Icahn, who has been a consistent critic of the Fed for keeping its benchmark interest rate close to zero since late 2008.