Nearly 30% of the world's billionaire population in 2018 was concentrated in just 15 cities, according to Wealth-X's 2019 Billionaire Census report. Strong tech industries have fostered considerable wealth in several cities, from San Francisco to Shenzhen. A large share of the world's billionaire population lives in eastern Asia, which has six cities on the list. Visit Business Insider's homepage for more stories. Billionaires are increasingly becoming concentrated in a cluster of cities, according to Wealth-X's 2019 Billionaire Census report. The report analyzed data from Wealth-X's global database of more than one million records of the world's richest people.