Actually, from the article it's unclear if he's beaten the S&P500 as an investor. It doesn't mention much about what he invested in before 1980, but it does say he lost about $50 million dollars in a margin call in 1982 so he was already quite wealthy either from BPI (the company started in ~1971) or from investing in the 60's/70's.
If his total investments at that time was $100 million, which seems somewhat reasonable given how much he lost in the margin call, investing that in the S&P500 would be worth $4 billion today, which is quite a bit more than the $2.3 billion he's actually worth.
That's also ignoring his currently $10 million a year income from BPI, so he could have spent 100% of that money.
If his total investments at that time was $100 million, which seems somewhat reasonable given how much he lost in the margin call, investing that in the S&P500 would be worth $4 billion today, which is quite a bit more than the $2.3 billion he's actually worth.
That's also ignoring his currently $10 million a year income from BPI, so he could have spent 100% of that money.