Japan's Softbank is attempting to buy a significant stake in Uber Technologies at a 30% discount of the taxi-hailing app's most recent valuation, according to reports.
Softbank is said to have teamed up with a group of investors - including Dragoneer Investment Group and General Atlantic - to fork out $6 billion (£4.5 billion) for a slice of the firm.
Such a move would value Uber at $48 billion (£36 billion), nearly a third lower than the $69 billion (£52 billion) valuation slapped on the firm at its latest round of fundraising.
Uber declined to comment.
The Press Association understands that the investment group is set to build an initial stake worth around $1 billion (£751 million) before buying further shares from existing shareholders and Uber employees that would bring its holding to around 14%.
But reports earlier this month already hinted that stock offers were likely to be based on a lower valuation.
Uber confirmed in mid-November that it had clinched an agreement with the investor group, saying it would help fuel technology investments and further expansion, but stopped short of providing further details.
The investment is expected to also pave the way for the company's much-awaited stock market flotation by the end of 2019.
The news comes as the ride-hailing firm battles increased competition in the US, where rival Lyft has recently gained backing from Google which is interested in promoting its self-driving technology, and has been squeezed in Russia by local competitor Yandex.
An Israeli court on Tuesday also ordered Uber to stop its ride-sharing operation in Israel less than a month after the service was launched in Tel Aviv.
In the UK, Uber is fighting to keep its service running in London and is to appeal against a tribunal ruling that its drivers were "workers" and entitled to the minimum wage, sick pay and paid leave.
Transport for London stripped the ride-hailing firm of its licence in September, raising concerns over Uber's approach to reporting serious criminal offences, how drivers' medical certificates are obtained, how criminal record checks are carried out, and its use of technology which allegedly helps it to evade law enforcement officials.
In another difficult episode for the business, investigators are now working to establish how many British Uber customers had personal information hacked during a mass data breach covered up by the taxi-hailing firm - which affected 57 millions drivers and customers worldwide.
Chief executive Dara Khosrowshahi, who took over in August, said two individuals outside the company "inappropriately accessed user data" in late 2016.
This included names, email addresses and mobile phone numbers, as well as the names and number plates of 600,000 drivers in the US.
Uber suppressed the incident by paying $100,000 (£75,500) to hackers so they would delete the data and keep the breach quiet, Bloomberg reported.