I always thought of him as ESTp. I read about him at Wikipedia just now and he seemed interested in starting charities even as a teenager which I found interesting. The reason I thought he was ESTp is because I had read how he seems to just aggressively capitalize on already existing services and products and has a penchant for adventurous and risky undertakings. For instance, he's starting up Virgin Galactic to sell flights to the edge of the space, but he didn't dream up the idea himself, he just saw other people working on the concept and decided to jump on the band wagon. But then again, I'm probably just engaging in stereotypes.