How do you pay for a megayacht?

Dear forum members,

I was wondering: If you purchase a nice "little" yacht for - let's say - 100 mln. USD... how do you pay for it? I suppose you are not going to show up with a truck load of cash and your credit card company is not going to settle this bill either... So, how does it work? Why are those individuals regularly NOT the legal owners of those yachts, but mostly companies?

Maybe someone can shed some light on the subject?

Best regards,
Olli