It'd be nice to know who and how they got their billions.

Are there any billionaires of whom it is not known how they got their billions?

There seem to be some, like Trump and SBF himself, who lied about making billions.

Jho Low until 2013.

Well, known by who? More of them are known to journalists and Google than to a proverbial person on the street, but there are supposed to be over 3,000 billionaires in the world.

We probably haven't heard of most of the 99% of billionaires that aren't in the top ten. And if we haven't heard of them, it would not make a lot of sense to be certain that "it is known" of all of them where they got their wealth.

Last year, if you didn't Google them, did you know who Bernard Arnault, Mukesh Ambani, or Gautam Adani were? In the case of Adani, I had never heard even of his company, which apparently is one of the largest in the world.

(The point of this post was mainly to use the phrase "99% of billionaires")

Obviously yes and there are billionaires whom it is not even known they are billionaires!

As one example of some discovered - https://www.bloomberg.com/news/articles/2014-05-08/three-mys...