Banks rarely expose this kind of fraud.
Heard that years ago, Equity lost huge sums to some guy(Chief IT admin) who was in charge of their servers. The guy had tweaked their software such that 50 cents would be wired to his account for every transaction. Guy made enough dough, did not renew his contract, sought UK citizenship, then went AWOL.
I could be wrong.
Live Full Die Empty - Les Brown.