Then there is the Giga Society whose few members claim to be in the top 0.0000001% in IQ (1 in a billion level IQ)
There are only 7 members, since there is slightly under 7 billion people in the world. Here is their website.
By the law of large numbers, I would have expected at least one member in China and/or India. Combined they have more than 1/3rd of the world population.
I've noticed mistakes throughout their site and their members are not exceptionally accomplished. So I'm skeptical of their superhuman brain powers. For example they claim six members on one page of the site and list seven members on a different page, I guess they're too smart to bother with counting.
They tried to impress me by spelling Gödel incorrectly as Gφdel.
Going to a Mensa meeting is a painful experience, so I wouldn't want to meet Giga Society Members. If they're anything like Mensa members, they must be ridiculously dysfunctional.
Here's a list of other High IQ societies