Interesting article on bank fraud
http://www.bankdirector.com/issues/articles.pl?article_id=12028&V=1
The higher incidence of employee misuse of information at banks could be due to the fact that bank employees simply have access to more sensitive and valuable information. While financial firms are fortified by better security than most other types of companies, these systems are designed for the express purpose of keeping bad guys out, not necessarily watching for the threat from within.
If the bank employee has a tie up with unsavory characters, it can be a problem.