If you google for "us bank data breach" you'll find plenty of examples of this happening and being disclosed. However banking regulations are strict and banks o

If you google for "us bank data breach" you'll find plenty of examples of this happening and being disclosed. However banking regulations are strict and banks own systems are designed to be resistant to insider attacks. So everything usually designed to keep different kind of data within bank own systems isolated and audited. In most of small and middle sized IT companies there is rarely any security measures against insider attacks or just accidental leaks if someone been too incompetent when it come to security. So leaks of sensetive data happen far more often since plenty of SWE and DevOps can easily get access to all the production databases. As result deployment of some single line fix in code of some critical system in a major bank might easily take 3-6 months.