Twenty-four-year-old Perenna Kei is the youngest and most mysterious billionaire on the list, with a wealth of US$1.3 billion. Born in Hong Kong and educated in London, she got her wealth from her father, the president of Logan Property Holdings Company Limited. He owns a leading real estate company in China, which listed in Hong Kong in 2013. Now Perenna Kei owns an 85 percent share of the company.