By putting "hundreds of billions" in currency in circulation, the central banks "can produce reflation—that's why we’re seeing the pop in oil, gold" and other commodities, he said in a live interview.

At the same time, "there’s the potential for deflationif the private credit markets can’t produce some sort of confidence and solvency going forward," Gross said. "So we’re at great risk here, not only in the U.S. but on a global basis."

Gross has previously predicted a "paranormal" market in 2012 characterized by "credit and zero-bound interest rate risk" and fewer incentives for lenders to extend credit.

He said stock and bond investors must lower their expectations when it comes to returns, with 2 percent to 5 percent as good as they get this year.