Short sellers are making their first bets on a retreat in Alibaba Group Holding Ltd. (BABA) a week after the company priced the world’s biggest-ever initial public offering. Bears who profit from price declines have sold short 8.9 million shares, or about 2.4 percent of Alibaba’s listed stock, according to data compiled by Bloomberg and Markit, a London-based provider of financial information. The Hangzhou-based company, China’s biggest e-commerce operator, sold 368.1 million shares in the IPO.