China\u2019s richest people are buying into Xiaomi Corp.\u2019s imminent Hong Kong initial public offering, conferring their imprimatur on the world\u2019s biggest coming-out party in two years. Former CK Hutchison Holdings Ltd. Chairman Li Ka-Shing, known in the former British colony as \u201cSuperman\u201d for his business acumen, plans to invest $30 million for an unknown slice of the Chinese smartphone maker, according to people familiar with the matter. Alibaba founder Jack Ma and Tencent Chairman Pony Ma - the country\u2019s two richest persons - have also agreed to take stakes in Xiaomi, said the people, who asked not to be identified discussing personal investments. The billionaire triumvirate joins a group of big corporate names backing an IPO that could raise as much as $6.1 billion - the world\u2019s biggest first-time share sale since Postal Savings Bank of China Co. raised $7.6 billion in Hong Kong in 2016. China Mobile Ltd., the nation\u2019s biggest wireless carrier, and U.S. chipmaker Qualcomm Inc. are among those that agreed to participate as cornerstone investors, according to terms for the deal obtained by Bloomberg. Li\u2019s participation could go down well with individual investors in Hong Kong, where the now-retired businessman enjoys near-celebrity status. He is investing through the Li Ka Shing Foundation, one of the people said. Li\u2019s deal was first reported by the Hong Kong Economic Journal. For the Mas, it\u2019s unclear which entity they would use to buy their stakes. Alibaba Group Holding Ltd. and CK Hutchison representatives had no immediate comment. Tencent Holdings Ltd. representative Jane Yip didn\u2019t respond to requests for comment.