Other investors in the fund raising round include private equity firm Silver Lake Partners, China Merchants Bank and Bank of Communications, two people familiar with the matter said.

They declined to be identified because they are not authorized to speak publicly. Didi Chuxing declined to comment.

The last valuation for Didi was $34 billion in August when it agreed to acquire Uber Technology’s China business following a drawn-out rivalry between the two firms. The deal gave Uber a one-fifth stake in Didi.

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At $50 billion, Didi’s valuation is propelled well above that of Chinese smartphone maker Xiaomi, which held the title of China’s most valuable startup after a 2014 funding round put it at $46 billion.

Ant Financial, China’s most valuable private internet finance firm and an affiliate of Alibaba Group Holding (BABA), is valued upwards of $60 billion.

The people said that part of the latest capital investment in Didi would be used for international expansion. Didi has sealed several overseas partnerships, focusing on intelligent driving, such as making use of artificial intelligence, as well as similar ride-hailing services.

The firm is ramping up overseas activity as regulatory changes are set to take a toll on their local service. Draft rules released in October would slash the number of eligible drivers and double fares for users in major cities, the company has said.

Since Uber exited the Chinese market last year, Didi has sought to expand in Latin America, leading a $100 million investment in Brazilian ride-hailing service 99 in January.

Last month it officially opened a lab researching artificial intelligence-related driving technologies in Silicon Valley in the United States. The company has previously entered a range of strategic agreements with U.S. tech firms including Lyft, TripAdvisor (TRIP), and Udacity.