Caporegime
Not sure, but many of them seem to be weirdly tight even though they can never spend it all.
I know one, has multi-millions. Buys used cars and clothes at charity shops. Has a large house but filled with largely used furniture.
Gets paid dividends from stocks and shares, just gets tossed on to the existing pile on money. No wild benders or shopping sprees etc.
The reason some people become wealthy is due to that particular mindset that can be difficult to change. They did not initially aim to make millions or buy supercars, rather, their wealth was a by-product of their success.