China's Alibaba says Q2 net profit up 159 pct

HONG KONG, Aug 27 (Reuters) - Top Chinese e-commerce firm Alibaba.com Ltd posted a 159 percent rise in second quarter net profit thanks to interest income from IPO proceeds, but its prospects are darkening as global woes cause small and medium sized firms to cut spending.

Alibaba, which operates an online business-to-business site connecting buyers and suppliers looking to import and export Chinese goods, is battling a turbulent macro outlook as it seeks to facilitate domestic Chinese and international trade.

On Wednesday, the firm -- in which U.S. Internet company Yahoo is a key investor -- posted a net profit of 396.46 million yuan ($57.87 million) for the three months ended June, compared with 153.14 million yuan in the same period last year.

That beat a forecast of 285.03 million yuan according to 3 analysts polled by Reuters.

Alibaba's shares debuted in Hong Kong last November in the city's most popular IPO.

But the stock plummeted nearly 32 percent during the quarter, amid ongoing concerns about the growth of its premium memberships as U.S. economic woes fan out across the world.

The stock easily underperformed a 3.3 percent slide on the benchmark Hang Seng Index .HSI. ($1=6.849 Yuan) (Reporting by Alison Leung; editing by Jonathan Hopfner)