HANGZHOU, China — Billionaires Jack Ma and Joseph Tsai are using their own money to buy back Alibaba Group Holding Ltd. shares as the company prepares to repurchase as much as $4 billion of its own stock.

The founders of China’s largest e-commerce company will participate in the buyback as affiliates, according to a regulatory filing. The filing didn’t disclose how much Ma and Tsai will spend.

Alibaba is trying to revive a share price battered by concerns about the slowdown in the Chinese economy less than a year after going public. Revenue at the Internet company rose 28 percent, the slowest pace in at least three years, to 20.2 billion yuan ($3.2 billion) last quarter.

Ma and Tsai have seen their personal wealth eroded by the share price plunge. Ma is currently worth $31.5 billion, according to data compiled by Bloomberg.

By Lulu Yilun Chen; editors: Michael Tighe, Suresh Seshadri, Edwin Chan.