Howard Marks, co-founder of Oaktree Capital Management, said it was time for the Fed to consider raising interest rates before it was too late.

"there are bubbles everywhere," Marks said in an interview on Thursday. "I'm not talking about today, but let's not miss the opportunity to raise interest rates."

Marks said the Fed should not hold back for fear of another "undersize panic". He points out that pension funds and many other institutional investors rely on returns of 7 per cent a year, but this may not be possible at 00:00, the federal funds rate.

Howard Marks, co-founder of Oak Capital, discussed his views on credit markets and Fed monetary policy with Erik Schatzker.

Oaktree is one of the world's largest investors in distressed debt. The Los Angeles-based fund usually thrives when the economy is in trouble because corporate bonds at risk of default fall sharply.

According to Marks, the current rate of return in the credit markets is the lowest in history. While it may still be more profitable than investing in US Treasuries, it is getting harder and harder.

"the returns have never been so low," he said.

In addition, Marks said Oaktree Capital plans to allow employees to return to the office on Sept. 13, but acknowledges that the spread of mutants may affect the plan.