Chinese ride-hailing giant Didi Chuxing, the company that bought Uber’s China business last year, has closed a $5.5 billion funding round, valuing the company at over $50 billion, making it one of the world’s most valuable private technology companies.

Didi said the round will be used “to support its global strategy and continued investments in AI-based technologies,” in a statement.

CNBC reported that Didi was in talks to raise a new round of money on Wednesday. On Friday, a source familiar with the matter told CNBC that the latest funding round values Didi at $50 billion.

This makes it on of the largest private technology companies behind Uber which is worth around $66 billion and Alibaba’s payment affiliate Ant Financial, which is worth $60 billion.

Didi declined to disclose the investors in the latest round or its valuation when contacted by CNBC. But sources told CNBC that previous backers Softbank, Bank of Communications, China Merchant Bank are involved, with Silver Lake being a new addition.

Uber and Didi were in an intense battle in China until last year when the Chinese firm bought the U.S. ride-hailing app’s business in the world’s second-largest economy. At the time, this valued the company at $35 billion. The latest valuation is significantly higher. Uber has a roughly 20 percent stake in Didi as a result of the transaction.

Didi founder and chairman, Cheng Wei, holds a non-voting seat on Uber’s board.