I’m pretty sure MBIA is not triple-A rated.
Ambac is the first one to be downgraded. MBIA is still triple-A:
“This was followed late Thursday by an announcement by Moody’s Investors Service (MCO) that the rating agency had placed MBIA on negative outlook for a possible downgrade from the insurer’s triple-A.”
http://online.barrons.com/article/SB120071150488302379.html?mod=yahoobarrons&ru=yahoo