* NIO is one of several largely Chinese-funded EV startups
* Would be second-biggest U.S. listing by a Chinese firm this year
* Firm posted net loss of $502.6 mln in H1 2018 (Updates with analyst comment, more details)
By Julie Zhu and Brenda Goh
HONG KONG/SHANGHAI, Aug 14 (Reuters) - Chinese electric vehicle start-up NIO on Monday filed for a $1.8 billion initial public offering of its American depositary shares, the biggest U.S. listing by a Chinese automaker.
The company, backed by Chinese tech heavyweight Tencent Holdings Ltd, applied for a float of up to $1.8 billion, according to its filing with the Securities and Exchange Commission.
It plans to go public on the New York Stock Exchange under the symbol "NIO".
The float comes as the firm, founded by Chinese entrepreneur William Li in 2014, and other Chinese EV makers seek fresh capital to develop new products and finance investments in areas including autonomous driving and battery technologies.
Having begun promoting EVs in 2009, China aims to become a dominant global producer as it bids to curb vehicle emissions, boost energy security and promote high-tech industries.
Start-up electric carmakers such as WM Motor Technology Co and Xpeng Motor have also raised funds totaling billions of dollars from heavyweight investors including tech giants Alibaba Group Holdings Ltd, Baidu Inc and Tencent.
NIO is also joining several sizable Chinese listings in New York this year, even as Sino-U.S. trade tensions involving tit-for-tat tariffs rattle global stock markets.
At $1.8 billion, NIO's IPO would also surpass the $1.63 billion float by online group discounter Pinduoduo Inc to become the second-biggest U.S. listing by a Chinese firm this year. Chinese video streaming service provider iQiyi Inc raised $2.42 billion from a Nasdaq IPO in March.
NIO, formerly known as NextEV, is one of several largely Chinese-funded EV startups betting on the benefits of local production to compete with firms such as Tesla Inc. Its other backers include investment firms Hillhouse Capital Group, Sequoia Capital and a private equity fund established by Baidu .
"NIO is just getting started early," said Yale Zhang, head of Shanghai-based consultancy Automotive Foresight of its IPO plans. "(China's) new energy car industry is just starting, it's a marathon process."
Other Chinese car and electric vehicle makers that are listed in the United States include Great Wall Motor Co Ltd, which has a over-the-counter listing, and Kandi Technologies Group.
NIO incurred a net loss of $502.6 million in the first six months of 2018, its statement said, on $6.95 million in revenues.
In June, it began customer deliveries of its ES8 pure-electric, seven-seat sport-utility vehicle, which the company sees as a rival to Tesla's Model X. It also plans to launch a second, lower-priced electric sport-utility vehicle, the ES6, by the end of this year.
NIO said it had delivered 481 ES8s as of the end of July and had unfulfilled reservations for another 17,000, of which 4,989 were ordered with non-refundable deposits.
NIO mainly plans to use the proceeds to be raised for research and development of products and technology, marketing and developing manufacturing facilities.
The company has hired Bank of America Merrill Lynch, Citigroup, Credit Suisse, Deutsche Bank, Goldman Sachs, JPMorgan, Morgan Stanley and UBS as underwriters. (Reporting by Julie Zhu in Hong Kong and Brenda Goh in Shanghai; Additional Reporting by Yilei Sun; Editing by Simon Cameron-Moore and Sam Holmes)