Standard & Poor’s released ratings changes to mortgage bonds on Friday based on a tighter methodology and stricter criteria.

S&P reviewed 1,358 ratings rom 241 residential mortgage-backed securities transactions issued between 2002 and 2007. The transactions were backed by Alternative-A, high loan-to-value and negatively amortizing mortgages.

Of those, S&P lowered ratings on 587 classes, with more than three notches on 202 of them. It raised 41 classes, with more than three notches on seven of them. S&P also affirmed ratings on 702 classes, withdrawing ratings on 28 classes. 

The downgrades are a result of an increase in redefaults and roll-rates for 30-day and 60-day delinquent loans, which reflects the falling house prices in the industry.

S&P is currently resolving 425 ratings, which were previously placed on CreditWatch.

Previously, S&P predicted a high number of CreditWatch negative placements because of an increase in the remaining transactions, with 43% downgrades of rating actions.

Big players such as Bank of America Mortgage Trust, Citigroup Mortgage Loan Trust, Deutsche Bank Alt-A Securities, Merrill Lynch Mortgages Investors Trust and Washington Mutual Mortgage Pass-Through Certificates had some of the highest average delinquencies.

Bear Stearns, Lehman and Taylor, Bean & Whittaker were alos some of the RMBS issuers.