UPDATE 1-Chinese online group Pinduoduo files for $1 bln U.S. IPO - source

* IPO of Tencent-backed firm could raise up to $1 bln - source

* Group discounting platform has 295 mln active users - filing

* “Pinduoduo Partnership”, not board to appoint CEO (Updates with sourcing on value of expected deal)

HONG KONG, July 2 (Reuters) - Chinese online group discounter Pinduoduo has filed with US authorities for an initial public offering (IPO) which, according to a source with direct knowledge of the matter, could raise up to $1 billion.

Walnut Street Group, the parent of Pinduoduo, made the U.S. Securities and Exchange filing on Friday. Loss-making Pinduoduo was formed three years ago and in the filing claimed 295 million active users of its mobile platform, which allows consumers to group together to increase the discounts offered by merchants.

The IPO of the company, which is backed by Chinese social media and gaming company Tencent Holdings, is looking to raise up to $1 billion, according to a source involved in the transaction, who declined to be named as details of the deal are yet to be finalised.

Pinduoduo did not immediately respond to requests for comment.

The company is the latest in a series of Chinese tech groups preparing to list in New York or Hong Kong even as trade tensions between China and the U.S rattle global markets.

Last week, Qeeka Home, a Chinese provider of online interior design services, postponed a $278 million Hong Kong IPO, while in New York, Uxin, a Chinese second-hand car sales site, halved the size of its planned float.

Revenues at Walnut Street Group have grown sharply, reaching 1,384.6 million yuan ($208.19 million) in the first quarter of 2018 from 37 million yuan $5.56 million) a year previously, according to the filing. Losses, however, remained broadly steady at 201 million yuan versus 207.7 million yuan a year previously.

The company will also be the latest Chinese tech group to opt for a governance structure other than the traditional one-share-one-vote model.

The filing outlines a “Pinduoduo Partnership” - a self-selecting group of senior executives - that will have the right, rather than the board, to appoint the chief executive and other executive directors.

The system is similar to the partnership than nominates board members at Alibaba Group Holding. Xiaomi , the smartphone maker whose shares begin trading in Hong Kong next week following a $4.7 billion IPO, has opted for dual-class shares, which give outsized voting weight to its founders over ordinary shareholders.

CICC, Credit Suisse and Goldman Sachs are advising Walnut Street Group, according to the filing. ($1 = 6.6508 Chinese yuan renminbi) (Reporting by Jennifer Hughes and Engen Tham; Additional reporting by Shanghai Newsroom; Editing by Muralikumar Anantharaman)