Alphamab Oncology (HKG:9966) said its controlling shareholder and CEO Xu Ting bought 554,000 shares of the company from the open market on Thursday, according to a Friday filing with the Hong Kong bourse.
The purchases were on top of the 122,000 shares bought by certain members of the company's management, also on the same day.
The shares were purchased for HK$7.375 on average, or nearly HK$5 million in total.
Xu now holds 314.28 million shares, representing 32.4% of the business, the firm said.