From that article: "After the IPO, the company was worth $1 billion, Mark Cuban was worth $300 million" (obviously a little more than the $100m I thought)
Cuban's position was worth more on paper at its peak before the Yahoo acquisition. Broadcast.com was acquired for $130 per share, the high that year before the acquisition, was $144 per share.
Prior to the acquisition, the stock was trading at $118. Yahoo only paid a 10% premium. Cuban was worth over a billion dollars before the acquisition.
https://www.cnet.com/news/yahoo-broadcast-com-sizzle-after-d...
The S&P 500 was 1300 when he sold to Yahoo. He received $1.4 billion of Yahoo (14.6m shares at $95/each). He had to pay taxes on clearing out that position as well, so you can safely assume his after tax position was more like ~$1.1 billion. He very solidly beat the S&P 500.
He's worth $4.08 billion today according to Bloomberg (ranked #500 on their global rich list). He has increased his net worth by nearly 4x.
The S&P 500 is at 2747. It has just over doubled since April 1999. He'd be missing a billion dollars if he had gone with the S&P 500, including any dividends.
He was better off with what he did, he beat the S&P 500 index fund. Not only did he make more money his way, he got to do what he wanted to with his money, such as buying the Mavericks.
$1.1 billion to $4.08 billion [1].
His primary business holding, the Dallas Mavericks, has increased in value from $285 million to $1.9 billion [2] (per the latest Forbes estimate). For that investment, he has seen a rate of value increase of about 11% per year. That investment stomps the S&P 500 massively (which was at ~1400 when the acquisition closed).
[1] https://www.bloomberg.com/billionaires/profiles/mark-cuban/
[2] https://www.forbes.com/sites/kurtbadenhausen/2018/02/07/nba-...
Very few money managers that are accessible to people with less than 10^8 USD can beat the S&P after fees.
Bridgewater, (Ray Dalio's fund mentioned above) regularly gets 12.5% annual returns and they are most notable for being consistent, not high. Pre-2008 some investment banks were getting up to 20%.
A billionaire making 7.5% annually is fairly unimpressive if their goal was to make money (which it might not have been for Cuban).