Chinese ride-hailing service Didi Chixung has successfully raised more than $5.5 billion from investors to bankroll an expansion beyond China and into driver-less technology.

Bloomberg reported Friday that Didi, which counts Apple as one of its backers, disclosed the latest round of financing in an emailed statement.

Didi has raised money from SoftBank, Silver Lake and other investors, becoming the most valuable startup in Asia and surpassing China’s handset maker Xiaomi.

The latest round of financing was said to have raised the company’s valuation to about $50 billion. The four-year-old firm now files as the world’s most valuable startup after Uber, which now owns a 17.5 percent stake in Didi after selling its Chinese business to them.

Since buying Uber’s China business in August 2016, the company’s market valuation increased to about $34 billion. But the service has experienced various challenges in China, a 1.33 billion people market, after cities like Beijing and Shanghai imposed stricter regulations that have crimped revenue growth.

Didi CEO Cheng Wei and President Jean Liu hope that adopting driverless technology will help overcome such hurdles in the future. Didi could take advantage of data on 400 million users across some 400 cities—plus, the money raised from investors—to fuel research into artificial intelligence and autonomous vehicles and fund its international expansion.

In May 2016, Apple announced a $1 billion investment in Didi. Tim Cook later said the deal would help his company “better understand the critical Chinese market.”

As of March, Didi runs an artificial intelligence lab in Mountain View, California, that focuses on the development of intelligent driving systems.

Photo: Apple CEO Tim Cook with Didi Chuxing’s president Jean Liu.

Source: Bloomberg