According to Inside Wealth Editor Robert Frank in conjunction with New World Wealth, the U.K. is destination for most millionaires. Countries that gained the most millionaires, 2003-2013 Rank Country Net gain 1 U.K. 114,100 2 Singapore 45,000 3 U.S. 42,000 4 Australia 22,200 5 Hong Kong 22,200 (Source: New World Wealth)