Taobao Mall, China’s largest business-to-consumer online marketplace by transactions value, has joined more than three dozen rivals in a move likely to shake up the country’s e-commerce sector.

Thirty-eight retailers including Yihaodian, the online grocer in which Walmart owns a stake, and Coo8.com, the online arm of electronics retailer Gome, agreed to open stores on tmall.com, the site operated by the B2C arm of Alibaba Group, China’s largest e-commerce group, the companies said on Monday.

The alliance is expected to strengthen Taobao Mall’s dominant position in the online retail industry and raise the cost for 360buy, its largest competitor, to guard or expand its market share. It comes as 360buy has started preparing for an IPO in which it hopes to raise up to $5bn.