The ultra-rich are getting ultra-richer. Boston Consulting Group’s latest Global Wealth report indicates that households with more than $100 million in wealth saw their holdings increase by 3.6 percent last year, the biggest increase among all segments measured. The so-called ultra-high-net-worth households held $7.1 trillion, or 5.8 percent of total global wealth; its estimated compound annual growth rate of 8 percent through 2016 eclipses all other groups. The United States still leads the world in the total number of UHNW households with 2,928 (the U.K. is next with 1,125, followed by Germany with a mere 807.) But the real action in global wealth accumulation can be found in developing economies; some of those areas will see UHNW growth rates in the double digits through 2016.