Moody's Cuts Credit Ratings Of 15 Large Banks

This article provides Moody's explanation for the ratings downgrade and some of the reactions to actions taken by Moody's.  It has been four years since the banks needed to be rescued by government.  Most have better capital positions, but their balance sheets and operating performance are not up to par.  The rating downgrade will make it more costly for the banks to raise money from the bond market and it might affect cause some customers to look for safer partners.  The banks may also seek to increase profits by raising fees for services that were provided free of charge.

There is more information in this article which lists the large global banks and places them in three categories of relative strength.