* Q2 net loss 496.4 mln yuan vs 252.3 mln yuan loss year prior
* Revenue up 43.6 percent to 93.2 bln yuan
* Says completed spin-off of JD Finance (Adds earnings breakdown, context)
Aug 14 (Reuters) - JD.com Inc, China's second-largest e-commerce firm, on Monday said its net loss widened in the second quarter, as marketing costs damped the impact of higher-than-forecast revenue growth.
China's main rival to Alibaba Group Holding Ltd reported net loss attributable to shareholders of 496.4 million yuan ($74.43 million), from 252.3 million yuan in the same period a year earlier.
That was on revenue which grew 43.6 percent to 93.2 billion yuan, well above its forecast range of 88 billion to 90.5 billion yuan.
Marketing expenses rose 63 percent to 4.1 billion yuan, mostly due to sales events in June.
The result comes as JD looks to expand overseas with investments in Southeast Asia, as competition at home intensifies while customer growth slows. It is also seeking to boost per-customer spend in China by bringing more overseas brands onto its local platforms through strategic partnerships.
JD in June said it intends to begin direct sales in Thailand before the end of the year and has plans to tap other markets in the region. It expanded its partnership with Wal-Mart Stores Inc during the second quarter and invested $397 million in fashion retailer Farfetch UK Ltd.
The firm expects revenue for the third quarter to be 81.8 billion to 84.2 billion yuan, a rise of 36 to 40 percent from the same quarter in 2016.
JD also said it has completed the spin-off of subsidiary JD Finance, which analysts expect will have long-term benefits for its operating margin.
JD Finance is now a fully Chinese-owned entity, giving it greater regulatory freedom.
JD.com also completed the internal separation of its logistics unit, which will look to serve more third-party clients outside of the group.
The total value of merchandise transactions on JD's platforms was 234.8 billion yuan during the quarter, up 46 percent.
JD booked a net loss of 0.35 yuan per American Depository Share, compared with a loss of 0.18 yuan a year earlier.
($1 = 6.6695 Chinese yuan renminbi) (Reporting by Cate Cadell in BEIJING and Rama Venkat Raman in BENGALURU; Editing by Christopher Cushing)