Skadden Arps Slate Meagher & Flom has acted opposite Simpson Thacher & Bartlett to advise on a merger between two of China's largest taxi apps, Didi Dache and Kuaidi Dache.

The rival companies, backed by Chinese internet giants Tencent and Alibaba respectively, will form a new entity that could be valued at $6bn (£3.9bn), according to the country's state news agency Xinhua.

Kuaidi holds a 57% share of China's taxi-hailing app market, while Didi accounts for 43%, according to consultancy Analysys International in December.

The growth in China's mobile transport market has been driven by a surge in the number of people using their smartphones to access the internet.

Skadden acted as international counsel for Didi on the deal, with a team headed by partners Julie Gao and Will Cai. Fangda Partners provided People's Republic of China counsel.

Simpson advised Kuaidi led by Hong Kong corporate lawyers Leiming Chen and Katie Sudol, with Han Kun Law Offices representing the company on Chinese law.

The decision to merge comes after Baidu, another top four Chinese internet company, said in December it was investing in US taxi company Uber.

It also follows an announcement last month by the country's Ministry of Transport that it would ban private cars from taking and charging passengers using taxi-hailing apps amid passenger safety concerns.

Under new rules, only vehicles owned by taxi or car-hire companies are allowed to take advantage of the service.