The mother of Jack Ma's private-equity fund partner became a billionaire following a higher valuation of Alibaba Group Holding Ltd's finance affiliate last week.

Wang Yulian owns 4.6 percent of Zhejiang Ant Small & Micro Financial Services Group Co, according to company filings obtained by Bloomberg News, making her the biggest shareholder in the parent of Alipay after Ma and Alibaba co-founder Simon Xie. She has a net worth of $2.4 billion, according to the Bloomberg Billionaires Index.

Wang is the 15th billionaire shareholder of Ant Financial. Twelve others emerged on Jan 30 after the company's valuation doubled to about $50 billion amid plans for a private placement ahead of an initial public offering, people familiar with the matter said.