Biographer Timothy O'Brien wrote a book, "TrumpNation", in which O'Brien cited Trump's own estimates of his wealth as ranging from $1.7 billion to $9.5 billion. O'Brien also cited much lower estimates of "three people with direct knowledge of Donald’s finances". Trump accused O'Brien of cherry-picking his information and sued O'Brien for $5 billion in damages.(1)
During a two-day deposition, Trump was asked, "You said that the net worth goes up and down based upon your own feelings?". To which Trump replied, "Yes, even my own feelings, as to where the world is going, and that can change rapidly from day to day."
The judge dismissed the case in 2009 and that decision was affirmed by a three-judge panel two years later. Timothy O'Brien, 2005 book, "TrumpNation: The Art of Being the Donald"(1)
“Donald, do you know that in order to be a billionaire, you have to have the ‘billion’ part in your bank account, not just the ‘aire.'”
Mark Cuban http://ftw.usatoday.com/2016/07/mark-cuban