Investors have become more cautious toward China's two biggest e-tailers, the Alibaba Group and JD.com, citing their growing competition and the escalating trade tensions between the U.S. and China.

In reporting its results for its second quarter ended on Sept. 30, which showed the lowest growth rate of the past two years in its core e-commerce business, Alibaba revised its sales projections for the full financial year downward by between 4 and 6 percent in view of the “current fluid macro-economic conditions.”

Alibaba's total revenues went up by 54 percent to 85.1 billion yuan (€10.8bn-$12.3bn) in the quarter, but while those from cloud computing shot up by 90 percent, revenues from core commerce rose by 56 percent to RMB 72.5 million (€9.2m-$10.4m). The group's adjusted Ebitda margin declined by nine percentage points to 31 percent, but its net income rose by 13 percent to RMB 20.03 billion (€2.5bn-$2.9bn), which was higher than analysts had expected.

The number of active customers in the group's Chinese marketplaces rose by 25 percent to 601 million in the 12 months through June 30. Alibaba revealed that 75 percent of its new users in the latest quarter were from underdeveloped areas of China.

While boasting 305.2 million active customer accounts for the last 12 months, half as many as Alibaba, JD.com reported a lower-than-expected sales increase of only 25.1 percent to RMB 104.8 billion (€13.3bn-$15.1bn) in the third quarter ended on Sept. 31. Citing lower demand for expensive items, it indicated that the growth rate will slow further down, ranging between 18 and 23 percent during the fourth quarter. It's a big decline from the record growth of 60 percent reached in 2015.

Net income fell to RMB 1.2 billion (€152.5m-$172.9m), half the level of one year ago, but it was a little higher than expected, in spite of high investments in research, drones and warehousing. However, the share price took a further beating, exacerbated by the fallout from the recent arrest in the U.S. of JD.com's chief executive, Richard Liu, on charges of sexual misconduct.