Jack Ma has officially stepped down from his role as chairman of Alibaba Group Holding Ltd. (BABA), the e-commerce giant he co-founded out of a Hangzhou-based apartment in September 1999. The announcement was made a year ago, and Ma remained in the role until Sept. 10, 2019 to ensure a smooth transition. In a letter, the charismatic 54-year-old said he will be succeeded by Daniel Zhang, a 12-year veteran at the company who became its CEO in 2015.