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/a

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-mysterious-philanthropists-fund-fourth-largest-u-dot-s-dot-charity https://www.bloomberg.com/news/articles/2014-05-08/three-mys...