Sam Altman invested $180 million into a company trying to delay death

Altman does not appear on the Forbes billionaires list, but that doesn't mean he isn't extremely wealthy. His wide-ranging investments have included early stakes in companies like Stripe and Airbnb. "I have been an early-stage tech investor in the greatest bull market in history," he says. Now, he is putting his capital to work at a level he calls an "order of magnitude" greater than he could during his Y Combinator days. And he has been concentrating those bets into a few areas of technology he thinks will have the biggest positive impact on human affairs: AI, energy, and anti-aging biotech.