There are probably a few Bitcoin billionaires out there. They aren’t all going to broadcast their wealth which is kind of the point if cryptocurrencies. We don’t want everyone to know what we have and where we have it. Even those of us that aren’t wealthy will most likely have multiple addresses that we use. I’m sure that the millionaires and billionaires have their Bitcoins spread out in different wallets. There’s almost no way to know how many Bitcoins people are holding.