"Alibaba Group is committed to the highest standards of business conduct, "the statement said.
The Alibaba statement did not provide any details on what Yang, who was arrested Monday, is alleged to have done. An Alibaba spokeswoman declined to comment on the company's SEC filing.
Police in Beijing and Hangzhou, the city where Alibaba is based.
Immediately after Yang's arrest, Alibaba named Fan Luyuan as the new head of Youku. Fan had already replaced Yang last month as rotating president of the company's digital media and entertainment division, which includes Youku and other businesses.
Alibaba's digital media and entertainment unit posted a loss of 3.8 billion yuan ($ 554 million) last quarter.