Chinese e-commerce company Alibaba Group Holding Ltd is investing more than $100 million in Mei.com, a “flash sales” platform for luxury and fashion goods, according to a source with knowledge of the deal. Alibaba had said earlier on Wednesday it would form a team within its Tmall business-to-consumer platform to help Mei.com expand its user base, product offerings, logistics and IT infrastructure, but did not disclose the size of its investment.