Influential rating agency Standard & Poor's said on Tuesday that it may downgrade $12 billion of subprime mortgage-backed securities because losses in this low-end part of the home-loan market have increased and will probably get worse.
Credit ratings on 612 classes of residential mortgage-backed securities (RMBS) backed by U.S. subprime collateral have been put on CreditWatch with negative implications, S&P said. Beginning in the next few days, the agency said most of these classes will be downgraded.
That covers about $12.078 billion in rated securities, or 2.13% of the $565.3 billion in U.S. RMBS rated by S&P between the fourth quarter of 2005 and the fourth quarter of 2006, the agency noted.
The agency said it's also reviewing ratings of Collateralized Debt Obligations (CDOs) that invested in the RMBS that could be downgraded. (CDOs are a bit like mutual funds that hold asset-backed securities. Many CDOs bought subprime RMBS, helping to fuel the housing boom earlier this decade.)
This is a really big story. I would add the following points:
1.) S&P is downgrading the underlying mortgage pools of certain CDOs. We have yet to see how this will effect the actual CDOs. While I don't think the implications are good, we'll have to see how this plays out.
2.) I would like to see a diffusion index of where these bonds are. If owership is spread out or concentrated.