4. Carsten Kengeter – The Investment Banker

Karsten Kengeter

He fought against the inevitable for months: his exit as boss of Deutschen Boerse. Suspected insider trading isn't picayune, but the German investment banker believed he could sweat out a prosecutor's probe.  

The former head of UBS' investment bank stumbled over a 4.5 million euro bonus scheme which quickly swelled in value to 34 million euros. The only wrinke? Deutsche Boerse might have already been in merger talks with the London Stock Exchange, or LSE, at the time.

Kengeter is lauded by former colleagues as being a man of integrity, but the taint couldn't be washed away without him stepping aside. The ex-CEO is likely to go back to private investments in fintech or even cryptocurrency.