Alibaba increased its stock buyback from $10B to $15B as the company is “confident of our long-term growth prospects” having bought $3.7B of the US stock since April 1st, 2021.
Source: https://www.forbes.com/sites/brendanahern/2021/08/03/alibaba-earnings-review-we-are-confident-of-our-long-term-growth-prospects/