I recall hearing a few years ago that the person who successfully develops an asteroid mining company will likely be the first trillionaire. I'm not sure how well that assumption holds up today.
That probably comes from proponents for lunar helium-3 mining. IIRC, the problem is that getting into space is still so expensive and vast improvements in fusion technology are still needed for the investment to be reasonable. But once cheaper space travel is developed and commercial fusion power generation is figured out, I could see helium-3 barons in the distant future.
I read an article a few years ago that predicted Jeff Bezos would be the world's first trillionaire in the 2030s. That still sounds about right, but it might happen sooner because of COVID.
