Shares of JD.com Inc. (JD-SW) tumbled 5.01% on Monday, as the e-commerce giant's lackluster performance during the recently concluded Singles' Day shopping festival added to investor concerns about China's slowing economic growth.

The annual Singles' Day shopping extravaganza, which kicked off on October 14 and culminated on November 11, is typically seen as a gauge of consumer sentiment in the world's second-largest economy. While JD.com reported a more than 20% year-over-year increase in shoppers, the company refrained from disclosing specific sales figures, a departure from previous years.

This year's Singles' Day event was the longest edition yet, but expectations for sales growth were muted amid a prolonged property crunch and macroeconomic slowdown in China. According to a Bain & Company survey conducted before the event, about three-quarters of respondents said they would spend the same amount or less on Singles' Day promotions compared to last year.