Donald Trump has been fond of reminding his followers that he's really really wealthy.  In fact his wealth has been presented as his success as a businessman and indeed as a person.  Despite this assurances that he is "really really rich" he's steadfastly refused to release recent tax returns that would allow his claim to be judged.  

Recent analysis by Bloomberg has put Trump's net worth about 2.8 billion.  Considering what we know about what Trump inherited if he had simply put his money in an index fund like the S&P he would we worth a whopping 13 billion.  Ergo for all his "deals", schemes, and scams he's about 10 billion poorer than if he had done absolutely nothing with his money but invest it.  Very stable genius, indeed.