The jumbo features that Moody's worries about include super senior support bonds, exchangeable securities, principal-only bonds, and pool interest-only bonds.
The talk has prompted speculation that the FHFA could lower the conforming loan limit to $400,000 or, as conservator of the GSEs, direct them to reduce high-cost loan limits.
Banking regulators believe delinquency rates on HELOCs soon may rise sharply upward as a significant number of second liens reach the end of their draw period.