Uber Technologies is close to securing an investment from a group that includes SoftBank (SFTBY) that would value its self-driving car unit at $7.25 billion, sources told the Wall Street Journal Wednesday. 

SoftBank, Toyota (TM) - Get Report , and Japanese auto-parts Supplier Denso Corp. (DNZOY) are expected to invest a total of $1 billion in the unit as part of the deal, which could be announced within the next few days, according to the Journal. 

The investment would add another layer to the company's pending initial public offering, which is scheduled for early May. 

The company plans to raise about $10 billion in its IPO at a valuation that could reach between $90 billion and $100 billion. While that is lower than some previous estimates, it would still be one of the largest market debuts ever. 

This isn't the first time Toyota has invested in Uber.

Last year, the automaker invested about $500 million in the company as part of an agreement to work jointly with it on its self-driving vehicles. That investment valued the company at $76 billion.