Suppose you win 100 million. What do you actually do with it? Banks only guarantee 250,000. Do you have to invest it? Is there anywhere you can just let it sit and draw interest?
Private wealth management. They take a large cut but it's worth it for most mega-rich folks. They will manage the money for you and invest it according to your goals. They spread the funds out into various investment classes to lower overall risk and they work full time moving money around to maximize gains. They also have access to tax experts who can advise on how best to minimize taxes.