London has by far the biggest concentration of ultra-wealthy people in Europe, according to a report by high-net-worth research firm Wealth-X—though about 60% of sales go to non-U.K. citizens. There are 5,955 ultra-wealthy individuals in London. This compares to 2,850 ultra-wealthy people in Paris and 1,775 in Zurich. Ultra-high-net-worth individuals can be defined as those with over $30 million in investable assets.