According to a comment made in USA Today by OnAnIsland
"...Alliance Data Systems Corporation (ADS) as the company responsible for the data loss. Epsilon SYSTEMS is the marketing branch of ADS which sells the information ADS collects from banks and merchants and is not a stable corporate idenity and could disappear tomorrow and reappear the day after as another shell in the ADS structure."
http://www.usatoday.com/tech/news/2011-04-04-epsilon-hacking...