Alibaba Group Holding Ltd. sold $4.5 billion worth of convertible bonds in one of the largest such offerings in recent years, as the company looks to buyback more shares and invest in its businesses.The Hangzhou-based company priced the seven-year notes, due 2031, with a coupon of 0.5% and a conversion premium of 30%. Orders for the bonds were multiple times oversubscribed, with demand from investors globally, a person familiar with the matter said, asking not to be identified because the inform...