howard marks
Billionaire investor Howard Marks.
  • Billionaire investor Howard Marks sounded the alarm on the commercial real-estate sector. 
  • The Oaktree Capital co-founder warned of mortgage defaults that could add stress to the US financial system. 
  • "We're very likely to see mortgage defaults in the headlines, and at a minimum, this may spook lenders," Marks said. 

Billionaire investor Howard Marks rang the alarm on commercial real estate in what he labels as "one of the biggest worries" US banks face today. 

In a Monday memo, the Oaktree Capital Management co-founder warned of a wave of mortgage defaults that could add stress to the US banking sector.