Fitch Ratings today downgraded 110 RMBS classes from 28 different Countrywide deals, while affirming 69 classes. There are too many deals to list here — see the Fitch release for the full list, registration req’d — but most of the downgrades hit mezzanine and equity tranches and most did not exceed one notch downward. That being said, it’s still an awful lot of downgrades. Fitch said that the collateral of the affected transactions primarily consists of 30- and 15-year fixed-rate mortgage loans extended to Alt-A borrowers and are secured by first liens, primarily on one- to four-family residential properties. As of the October 2007 distribution date, the affected transactions are seasoned from 10 to 27 months; Countrywide Home Loans Servicing, LP is the master servicer on all of the transactions. Affirmations affected $13.4 billion of outstanding certificates. Downgrades affected approximately $337.7 million in outstanding certificates, as well as affecting classes placed on Rating Watch Negative, approximately $48.8 million of outstanding certificates. Fitch said losses in downgraded classes were outstripping credit enhancement levels. For more information, visit http://www.fitchratings.com.