Lehman Mortgage Trust 2008-4

Today, Standard & Poor's Ratings Services downgraded pieces of a 2008 re-REMIC from AAA to just CCC... The deal is Lehman Mortgage Trust 2008-4, and the class is A2. That their ratings can change so dramatically and so suddenly is shocking (Moody's had cut its ratings on the same paper to just C more than 5 months ago). The press release indicates that "although this performance deterioration is severe, the credit enhancement within LMT 2008-4 is sufficient to maintain the rating on class A1." S&P's current projected loss for the pool already stands at 14.74%. Is there enough subordination under class A1 to make any loss on it highly improbable? I don't think so. And in fact, Class A1 was downgraded by Moody's to just B3 five months ago already...

Let's note also that it took only 11 months for the top notes of the re-REMIC to lose its AAA rating from Moody's and S&P: the deal was issued in June 08, and Moody's downgrade took place on May 15 this year.