Shares of Tencent Holdings, China's largest internet company by revenue, fell by as much as 5% in Hong Kong.
Its second-quarter net profit rise came in smaller than expected.
Tencent attributed the smaller-than-expected profit increase to higher marketing costs for its WeChat social messaging service.
For the year-to-date Tencent is still up nearly 43%, compared with the 0.5% loss for the Hang Seng benchmark.
Second-quarter net profit rose to 3.7 billion yuan ($604 million) from 3.1 billion yuan a year earlier, Tencent said in a filing to the Hong Kong stock exchange.
Analysts were expecting on average a 4.1 billion yuan profit.
Increased marketing costs for WeChat, which rose to 9% of revenues from 6% year-on-year, came as the company continues its drive to market and then monetise the app through games, emoticons, like stickers and a mobile payment system.
Tencent, which is more than 30% owned by South African media group Naspers, is still the best performer on the Hang Seng Index this year.