Didi Chuxing is reportedly considering a $6 billion investment backed by SoftBank Group

Didi Chuxing, the largest ride sharing app in China, is deliberating a proposed $6 billion investment backed by SoftBank Group, according to a report in Bloomberg.

Bloomberg says that if completed, “the funding would be the single largest for a Chinese technology startup on record.” But the potential round’s massive size means it could dilute other existing shareholders. As a result, Didi Chuxing backers Apple and Tencent are thinking of joining the investment on a pro rata basis in order to avoid diluting their stakes.

SoftBank is already an investor in Didi Chuxing, one of an international roster of ride sharing companies, including Ola and Grab, it began backing in 2014.

It’s not clear if the $6 billion round would come from SoftBank Group or its $100 billion SoftBank Vision Fund, which is expected to close soon and also counts Apple among its investors.

Other big names among Didi Chuxing’s roster of more than 100 investors include Alibaba (the e-commerce company is itself another SoftBank investment) and Foxconn Technology Group. Didi Chuxing, which agreed to buy Uber China last summer, reportedly reached a $34 billion valuation after Foxconn’s $120 million investment last fall.

If Didi Chuxing does indeed accept the $6 billion in new funding from SoftBank, a good chunk of the capital would probably be poured into the development of self-driving vehicles. The company recently opened an artificial intelligence lab in Silicon Valley and has poached talent from Alphabet’s Waymo and Uber, two of its biggest rivals in autonomous driving tech.

While Didi Chuxing is the biggest company of its kind in China and no longer has to worry about competition from Uber China, it still has other rivals to fend off for market share. For example, UCAR, a competitor, recently raised a total of $1 billion. Other competitors include Yidao, backed by LeEco, and ride sharing services by e-commerce company Meituan and automaker Geely.

Didi Chuxing also has to cope with new regulations that limit its driver pool in Beijing, Shanghai and other cities.