[Update 1: Adds prime jumbo data from Amherst Securities Group.] Delinquency of more than 60 days among prime jumbo residential mortgage-backed securities (RMBS) nearly tripled to 9.2% in December 2009, from 3.2% at the end of 2008, according to Fitch Ratings. The '06-'07 prime jumbo RMBS vintages alone rose to a combined 12.7% delinquency rate, Fitch notes, from 4.3% a year earlier: Defaults in non-private-label securitizations of jumbo loans for all years [pictured above, in red] is on the rise, inching toward 7% as of October 2009, much in line with other collateral types, according to Amherst Securities Group. A jumbo mortgage has an initial principal amount above the $417,000 conventional loan limit set by Fannie Mae (FNM) and Freddie Mac (FRE). In higher-priced markets the limit is $729,750, and, in October, appropriations committees in both the House and Senate proposed an extension of the limit through 2010.