This would represent a minority stake in the self-drive division, giving Uber some additional backup ahead of its planned IPO, the Wall Street Journal, Financial Times, Reuters and the New York Times are reporting.

Investors are nervous about the division’s steep losses and lack of revenue and have been pushing Uber CEO Dara Khosrowshahi to spin it off or seek outside investment. SoftBank became Uber’s largest shareholder last year when it paid $7.7 billion for a 15% stake in the company. Toyota invested $500 million in Uber’s autonomous driving division in August 2018.

SoftBank and Toyota have a separate $17 million autonomous driving endeavor called Monet Technologies, and SoftBank has previously invested $2.25 billion in General Motors’ autonomous car unit, Cruise.

The Japanese multinational conglomerate is also home to the Vision Fund, the biggest technology fund in the world. CEO Masayoshi Son said last week he had invested more than $70 billion of the $100 billion fund; recipients also include Doordash, WeWork and Slack. Other partners include the sovereign wealth funds of Saudi Arabia and Abu Dhabi, which have contributed two-thirds of the total pledged capital, according to WSJ.

SoftBank itself went public in December, raising $23.5 billion, which made it the biggest ever Japanese IPO and the second-largest IPO worldwide after Alibaba’s $25 billion market entry in 2014.

Uber’s IPO is likely to come in May or June, and bankers expect the company to seek a valuation of as much as $120 billion. Rival Lyft will beat it to market by at least a few weeks, potentially with a valuation of $20 billion to $25 billion. Lyft was last valued at $15.1 billion.