NEW YORK, United States — Shares of JD.com, China's second-biggest e-commerce operator, had their biggest gain since January after first-quarter revenue topped analyst estimates.

Analysts highlighted margin improvement and a strong second-quarter sales view. Citi said that while many investors anticipated a strong report, JD’s forecast for a re-acceleration of revenue growth was better than expected and indicates “strong business momentum.” Bloomberg Intelligence expects margins will steadily improve with increasing scale in direct sales and better capacity utilization at the third-party logistics business.

JD’s American depositary receipts rose as much as 11 percent in New York before paring gains. The stock has gained almost 40 percent so far this year, outperforming rival Alibaba Group, which is up 29 percent. Alibaba reports fiscal fourth-quarter results on May 15.

By Catherine Larkin in Chicago; Editors: Courtney Dentch, Steven Fromm