The ranks of the ultrawealthy are growing fast, and their money is driving up high-end real estate prices. According to “The Wealth Report” for 2018 from London-based real estate consultancy Knight Frank, the number of people worldwide with at least $50 million in net worth increased 10% in 2017, to 129,730. Meanwhile, Knight Frank’s PIRI 100, an index of real estate prices in the world’s top 100 markets, gained 2.1%, vs. 1.4% in 2016. Leading the way was Guangzhou, China, where values shot up 27.4%, even as price growth in Shanghai and Beijing slowed. Europe placed four cities—Amsterdam, Frankfurt, Paris, and Madrid—in the top 10.