Billionaire wealth dropped globally for the first time in 15 years. : The world’s billionaires saw their overall wealth drop last year — the first time that has happened in 15 years, according to the 2019 UBS/PwC Billionaires Report released on Friday. Billionaires’ wealth fell 4.3% globally, dropping by $388 billion to $8.5 trillion last year. “The billionaire boom of the past five years has now undergone a natural correction,” explained Josef Stadler, the head of ultra high net worth at UBS Global Wealth Management, in a statement.