* DouYu IPO may be among largest by Chinese firms in US this year
* DouYu is China's largest game-streaming platform - prospectus
* Live-streaming is booming industry in China
By Julia Fioretti
HONG KONG, April 23 (Reuters) - China's largest live-streaming platform DouYu International Holdings Limited, backed by social media and gaming giant Tencent Holdings Ltd , has filed for a U.S. initial public offering (IPO) of up to $500 million.
DouYu, which primarily focuses on the live-streaming of games, is one of several Chinese start-ups in the growing market for live-streaming in China, along with U.S.-listed rival Huya Inc and Huajiao.
The rapid growth of the live-streaming sector has seen China's tech heavyweights - Tencent, Alibaba Group Holding and Baidu Inc - open their wallets to back a slew of firms in the hope it can boost existing services in e-commerce, social networking and gaming.
DouYu has exclusive streaming rights to 29 major tournaments in China, including League of Legends, PlayerUnknown's Battlegrounds, and DOTA2, according to the draft prospectus which was uploaded to the U.S. Securities and Exchange Commission website overnight on Monday.
DouYu was the largest game-streaming platform by average total monthly active users (MAUs) on both mobile and PC during the fourth quarter of 2018, according to the prospectus. The company had 159.2 million MAUs in the first quarter of 2019, representing year-on-year growth of 25.7 percent.
It set a placeholder sum of $500 million for the IPO, which is used to calculate registration fees. The final IPO size could be different, though sources have previously told Reuters DouYu was looking to raise around $500 million.
DouYu's IPO could be one of the largest this year by a Chinese company in the United States, together with that of Starbucks challenger Luckin Coffee which also filed overnight.
Chinese companies have raised $271 million through U.S. IPOs so far this year, with the biggest deal being that of Ruhnn Holding Limited which raised $125 million, Refinitiv data showed.
China is the world's largest game streaming market, with approximately 4.9 times the monthly active users of the U.S. market in 2018, the prospectus said.
DouYu's active users spent an average of 54 minutes per day on the platform in the fourth quarter of 2018.
DouYu is still loss-making and reported a net loss of $127.4 million in 2018, up from $91.33 million in 2017. Revenues jumped 94 percent to $531.5 million last year.
The company significantly increased its sales and marketing expenses - which jumped 73 percent in 2018 - as well as its research and development expenses which increased 55 percent.
Most of DouYu's revenues come from live-streaming through the sale of virtual gifts, accounting for 86.1 percent of its revenues, with the rest coming from advertisements and some revenue sharing with game developers and publishers, the prospectus showed.
Bank of America Merrill Lynch, JPMorgan and Morgan Stanley are the underwriters for DouYu's IPO.
($1 = 6.7109 Chinese yuan) (Editing by Jacqueline Wong)