Donald Trump inherited a lot of money and the growth of his wealth has been in line with that of the S&P 500.
Donald Trump's self-described net worth was $200 million in 1982.
If he invested that money in the S&P 500, he'd be worth about $8.3 billion today.
Today he claims his net worth is $8.7 billion. So based on his own claims, he has barely outperformed the S&P since 1982.
Some articles claim that Donald Trump's inheritance was somewhere between 40 and 200 million in 1974.[2][3] Here's one of those estimates:
Trump took over a $200 million real-estate-development business from his father, Fred Trump, in 1974. Dáte estimates that Trump's share of the empire — he has three siblings — was $40 million.[6]
Since 1974, the S&P 500 is up about 74-fold. So his current claimed net worth of 8.7 billion would equate to about 120 million in 1974, which is right in the middle of estimates of what he inherited.
His performance was very close to that of the market from 1982 to present, and possibly from 1974 to present.
If he spent a small percentage of his net worth each year, it's possible her outperformed the market over time. If his inheritance was at the low end of those estimates, he outperformed more. It's also possible he received some money from his father prior to that inheritance. If that's true or if his inheritance was at the high end of those estimates, then he underperformed the market.
Another way to look at the data is to assume he inherited $40 million in 1974, at the low end of estimates. If he had invested that $40 million in an S&P 500 index, fund, he'd be worth about 3 billion today — which is in line with third party estimates of 3 and 4 billion today for his net worth.
Regardless, the inescapable conclusion is that a very large percentage of his net worth is the result of inheritance and normal compounding.