Sogou Inc, one of China's leading search engines and a major competitor of Baidu, filed documents on Friday with the U.S. Securities and Exchange Commission (SEC) for IPO.
The proposed IPO aims to raise up to 600 million U.S. dollars, the prospectus showed but did not unveil the number of shares to be offered and the price range, according to the prospectus.
As a subsidiary of Chinese Internet and gaming company Sohu, Sogou has been the second-largest mobile search engine in China after Baidu.
Sogou Search accounts for 16.9 percent of market share in China based on mobile queries in June 2017, with 483 million mobile monthly active users (MAUs), according to data from Internet consultancy iResearch.
Meanwhile, the company's Sogou Input Method is the largest Chinese language input software by both mobile and PC MAUs in June 2017, data from iResearch showed.
Tencent is the largest shareholder in Sogou, though the stake carries less voting power than Sohu's 39 percent stake.
As a social giant in China, Tencent is key to Sogou's traffic. About 38.2 percent of search traffic to Sogou came from Tencent's products, according to the prospectus.
Sogou has recorded a revenue growth from 322.9 million US dollars for the six months of 2016 to 373.2 million US dollars for first half of this year.
Search and search-related advertising services represented 90.4 percent and 88.1 percent revenue respectively in the past one and half year, according to the prospectus.