The global population of billionaires is now 2,101, up 38.9 percent from five years ago, the Swiss investment bank UBS announced Friday. The combined wealth of the world's billionaires reached $8.5 trillion in 2018, a 38 percent increase from 2013, according to the report "The Billionaire Effect" by UBS and professional services firm PricewaterhouseCooper. Billionaire wealth declined $388 billion in 2018, after five years of growth, because of "a strong ...