No single company controls more than 20 per cent of China's market for business-to-consumer (B2C) online sales, a locally-based research firm reports.

Local Amazon subsidiary Joyo.com is the second largest online retail site with 16 per cent of the market. 

China's leading online B2C firm measured by number of registered users is Dangdang.com, which holds 19 per cent of the market, according to estimates from Beijing-based research consultancy Analysys International. 

While Joyo and Dangdang control roughly one third of the market, no other firm has more than a four per cent share.

US-based consumer products retailer Newegg has an estimated two million registered users in China, or about three per cent of the country's total. 

Giant online retailer Amazon first invested in Joyo in 2004, at which time it was generally consider China's leading B2C provider.

However, although Dangdang appears to have grown faster since then, both firms are losing money, according to analysts.

Amazon founder Jeff Bezos announced on a visit to China earlier in June that his firm would increase its stake to take control of Joyo, and was changing the company's name to Joyo/Amazon.

"Amazon is contributing its extensive technology and expertise to make Joyo the very best in the world at serving customers," said Bezos. "We are very proud to be associated with them."

Bezos has claimed that Joyo is experiencing "triple digit growth", according to recent press reports.

China's B2C websites had 68 million registered members by the end of the first quarter, estimates Analysys International. Joyo has 10.87 million, while market leader Dangdang has 12.95 million.