Earlier quoted context omitted.
Given the enormous scale of the fraud, someone should definitely be going to prison. "But my criminal organization is very large and not everything we did was illegal" is not an excuse.
Enormous scale? The total fees from this fraud were $2.4 million. https://www.bloomberg.com/view/articles/2016-09-09/wells-far... The "excuse" is that a bunch of employees did it against management's express instructions, and that management actually took action (albeit stupid ineffective action) to prevent it back in 2014. https://www.bloomberg.com/view/articles/2016-09-19/tough-tar... This is not something that was…
All banks have large internal audit departments precisely for the purpose of catching internal fraud. This is a long standing thing in banking and well established.
The idea that Wells Fargo's internal audit department missed several thousand employees carrying out the same kind of fraud over a period of years is entirely unbelievable.
So either the Internal audit team were in on it (extremely unlikely), internal audit were directed by management not to investigate this, or management ignored the reports for internal audit.
To me, its extremely likely that the later options there are more likely to be what happened.