Jack Ma, Chairman of Alibaba Group Holding.

When a fast-growing private equity firm co-founded by Jack Ma sought funding from institutional investors for the first time in early 2013, almost all had one major concern, its chairman said: was the firm independent from Ma, the influential executive chairman of Alibaba Group Holding, China's e-commerce giant.

The investors were worried that Yunfeng Capital might not put their interests first, said David Yu, a long-time friend and business associate of Ma, speaking to Reuters in a rare interview at his Hong Kong office on July 3.