SoftBank Vision Fund is selling $245m of shares while PayPal is investing $500m in the ride hailing service, in the world's largest IPO since 2014.
SoftBank is mulling the possibility of taking its $98.6bn Vision Fund public and is in talks with Oman over a commitment to a second fund.
SoftBank Vision Fund owns more than 7% of the enterprise messaging platform developer, which could list at a valuation near $17bn.
Uber is set to raise $7.9bn to $9bn if it floats within its range, while PayPal has agreed to invest another $500m through a private placement.
Qualcomm-backed visual social media platform Pinterest floated above its range in an offering that will give it a market cap near $13bn.
Zoom is floating above its range in an IPO in which Qualcomm will make an immediate $30.6m return, while Salesforce is buying $100m of shares through a private placement.
SoftBank Vision Fund and Alphabet are among the largest shareholders in Uber, which has filed for an offering that could value it at $100bn, a decade after it was founded.
The Alphabet, Rakuten, Alibaba, Didi Chuxing, GM, Jaguar Land Rover, Magna and Icahn Enterprises-backed ride hailing service floated at the top of its range at a reported $24.3bn valuation.