Simpson Thacher & Bartlett is acting opposite Skadden Arps Slate Meagher & Flom on what has been dubbed the biggest acquisition by a Chinese internet company in history – Alibaba's buyout of mobile browser UCWeb.

The Hangzhou-based e-commerce giant, which already owns 66% of UCWeb, is taking steps to acquire the rest of the company as it seeks to boost its profile in the mobile web market, where rival Tencent is currently a leader due to the success of its messaging services WeChat and QQ.

The value of the deal has not been disclosed, but sources say it has far surpassed the $1.9bn (£1.2bn) paid by Baidu to acquire the entire share capital of app store 91 Wireless last July – where Alibaba was also a bidder.

It follows the company's purchase of digital mapping company AutoNavi for $1.58bn (£947,000) in February – a similar move by Alibaba to increase its presence in the mobile market, but specifically in the arena of navigation and map applications.

Simpson Thacher acted for Alibaba on the deal, having previously been lead counsel on the Autonavi deal and also appointed to advise the company on its upcoming US IPO.

Lead partner was Hong Kong based Katie Sudol, who leads Simpson's M&A practice in Hong Kong, working alongside PRC counsel Jonathan Zhou from Chinese firm Fangda.

Skadden represented UCWeb on the deal, with corporate partner Julie Gao leading a team.

Gao continues to be among the lead advisors for Chinese technology companies, having previousl acted for a whole host of companies – such as Weibo, 21Vianet Group, Renren, Baidu, Jumei and 58.com – on their US listings.

PRC outfit Jingtian meanwhile provided Chinese law advice for the mobile browser, with partner William Huang leading a team.

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