OLDWICK, N.J.--(BUSINESS WIRE)--A.M. Best has placed under review with negative implications the financial strength rating (FSR) and the issuer credit ratings (ICR) of the insurance subsidiaries of ACE Limited (ACE) (Zurich, Switzerland) [NYSE: ACE], as well as the ICR and senior debt ratings of “a+” of ACE. (Please see link below for a detailed listing of the companies and ratings.) The rating actions follow the recent announcement that ACE entered into a definitive agreement to acquire The Ch