Alibaba Group Holding Ltd will buy back as much as $4 billion of stock as it tries to revive a share price battered by concerns about the slowing Chinese economy less than a year after going public.

The e-commerce operator will buy the shares over a two-year period, mainly to offset dilutions such as from its compensation programs. Wednesday's announcement came as the company posted first-quarter sales that rose at the slowest pace in at least three years and posted transaction volumes that missed estimates. Shares fell more than 6 percent in pre-market trading.

Alibaba's plunge in market value of about $100 billion, a decline bigger than Goldman Sachs Group Inc since November has been driven by a Chinese economy expanding at the weakest rate since 1990 and lawsuits concerning sales of counterfeit goods.