China e-commerce giant JD.com (JD) on Wednesday beat analyst expectations for the second quarter, reporting that merchants using its marketplace more than doubled to a record high. But U.S.-listed JD stock fell 5% in morning trades, underlining concerns about consumer spending in China. The Beijing-based company reported adjusted earnings of 74 cents per share on net revenue of $39.7 billion. Analysts polled by FactSet expected JD to report adjusted earnings of 68 cents a share on revenue of $38.6 billion. Net revenue for JD stock was up 7.5% compared with the second quarter of last year. That includes a 30%...