John Mack, former chairman and CEO of Morgan Stanley, told CNBC on Monday he sees "geopolitical risk" as the biggest threat to global prosperity and financial markets.
"Hopefully, nothing happens. But there's a lot of turmoil, whether it's in the Middle East ... North Korea ... or China and their [disputed] islands," Mack said on "Squawk Box," citing the risk of a "geopolitical blow-up" as his top concern.
"All it takes is for one person to make a mistake. And then you have a global event," he added in a wide-ranging interview that included his thoughts on the United Kingdom vote Thursday on whether to stay in the European Union trading block.