You can't have it both ways; those 6 bankruptcies are just properties too.
So with your wording you should say Trump owned 500 properties and 6 of them lost money. And like any real estate investor, when the properties lost money, Trump gave those 6 properties to the creditors.
But I think my wording is more accurate. Your friend's rental properties may not be individual businesses, but Trump Tower or the Taj Mahal are.
Trump Tower and Taj Mahal are real businesses. But most of trumps "businesses" aren't. They are just shell companies to hold assets.
The vast majority of his businesses have no customers, and no regular income. They aren't intended to make a profit--they're intended to protect an asset from the bankruptcy of his real businesses. There was never any chance that they would need to go bankrupt, so he gets no credit for them not going bankrupt.
> they're intended to protect an asset from the bankruptcy of his real businesses
Even if you were right about Trump's businesses, corporations don't work like that. The stock can be taken in bankruptcy so they don't protect assets inside the corp from bankruptcy of the holder. They only protect assets outside the corp from bankruptcy of the corp.
So with your wording you should say Trump owned 500 properties and 6 of them lost money. And like any real estate investor, when the properties lost money, Trump gave those 6 properties to the creditors.
But I think my wording is more accurate. Your friend's rental properties may not be individual businesses, but Trump Tower or the Taj Mahal are.