(Adds details from earnings release, executive comments and context)
By Cate Cadell
BEIJING, Feb 28 (Reuters) - JD.com Inc, China's second largest e-commerce firm, reported a 22.4 percent jump in quarterly sales on Thursday, beating estimates on the back of robust retail sales and sending its U.S.-listed shares up 13.8 percent in pre-market trade.
The results, however, still represent the company's slowest quarterly revenue growth rate since its 2015 initial public offering, as an economic slowdown hits China's top ecommerce companies.
JD.com's sales are seasonally high in the fourth quarter due to promotions surrounding "Single's Day", a China-wide online shopping frenzy that peaks on November 11.
The company said sales for the event peaked at 159.8 billion yuan ($23.9 billion), up 26 percent from a year earlier.
Its shares are up 24 percent this year, recovering after slower sales growth and the temporary arrest of chief executive Richard Liu sent stock down in 2018.
Analysts and executives in the industry have pointed to lower sales of big ticket items, including smartphones and appliances, as the driving factor behind slower sales growth on JD.com and competitor Alibaba Group Holding Ltd.
"Electronics appliances were impacted in the fourth quarter," said chief financial officer Sydney Huang on a call with analysts on Thursday. "At this point it's tough to tell, but we are cautiously optimistic for the second half of this year," he said.
The company has invested heavily in offline retail, finance and logistics services to diversify outside its e-commerce business.
It also announced on Thursday that its luxury e-commerce business "Toplife" will merge with the China unit of London-based online fashion retailer Farfetch. The deal will expand JD.com's luxury offerings as it faces fierce competition from Alibaba's Tmall.
Chief Executive Richard Liu on Thursday said the company will also focus on expanding into smaller Chinese cities in 2019, boosting investments in offline retail technology and logistics.
JD.com forecast March quarter revenue between 118 billion yuan and 122 billion yuan. That compares to a consensus analysts' estimate of 119.48 billion yuan according to IBES data from Refinitiv.
JD.com, which is backed by Walmart Inc, Alphabet Inc's Google and China's Tencent Holdings, posted a net loss of 3.32 yuan or 48 cents per American depository share, compared with a loss of 0.64 yuan a year earlier.
Full year revenue for 2018 was 462.02 billion, up 27.5 percent from 362.3 billion in 2017, beating analyst expectations and China's wider internet industry, which has seen full-year revenue rise on average 20.3 percent, according to China's industry ministry. ($1 = 6.6854 Chinese yuan renminbi) (Reporting by Cate Cadell and Munsif Vengattil editing by Patrick Graham/Keith Weir)