Fitch Ratings today made massive downgrades on various vintage '05 through '08 subprime residential mortgage-backed securities (RMBS), indicating the extent of the fallout related to subprime defaults has yet to subside. The rating agency slashed hundreds of RMBS ratings further into junk territory. Handfuls of Wells Fargo Home Equity RMBS saw ratings drop to single-C from double-C and to single-D from single-C. A variety of JPMAC RMBS fell to double-C from triple-B and many from double- and triple-C to single-C. A handful of CitiGroup RMBS fell to single-C from double- and triple-C and others to single-D from single-C. Fitch said the actions reflect updated expectations of default and loss from the relevant collateral pool. In terms of losses, the agency expects 17% of the original pool balance of the '05 vintage, 39% of the '06 vintage and 47% of the '07 vintage. "The home price declines to date have resulted in negative equity for approximately 50% of the remaining performing borrowers in the 2005-2007 vintages," Fitch says in a media statement today. "In addition to continued home price deterioration, unemployment has risen significantly since the third quarter of last year, particularly in California where the unemployment rate has jumped from 7.8% to 11%." Write to Diana Golobay. Disclosure: The author held no relevant investment positions when this story was published. Indirect holdings may exist via mutual fund investments.