Standard & Poor's Ratings Services has lowered its ratings on 99 classes from six RMBS transactions.
The securities, issued between 2005 and 2007, are backed by U.S. subprime and alternative-A credit mortgages as well as prime credit jumbo loans.
S&P said 42 of the 99 classes were on its CreditWatch list for possible downgrades and now have been removed from that list.
The credit rating agency also affirmed its ratings on 31 classes from four affected MBS and removed two of the affirmed ratings from its CreditWatch negative list.
