...study, the average cost per incident where PII has been put at risk is $6.3 million to investigate the breach, notifycustomers, restore security infrastructures, and recover lost business. They calculate that this amounts to about...
http://news.zdnet.com/2100-9595_22-358524.html
...prevent it from occurring in the future. For particular industries and types of breaches, you might have to notifycustomers and the general public, particularly if customers might be affected directly by the incident. If the event caused...
http://technet.microsoft.com/library/cc700825.aspx