The timing of the listing was still unclear as money-losing PayPay needs to first demonstrate a clear path to profitability, the source said.
SoftBank has previously set a PayPay listing as a goal, with one executive saying in November it was worth just under 1 trillion yen ($7.17 billion).
Representatives for PayPay and SoftBank Group's (9984.T) domestic telecoms business, SoftBank Corp (9434.T), said they would not comment on speculation.
PayPay is owned by SoftBank Corp, its internet business, Z Holdings (4689.T), and the group's second Vision Fund.
PayPay booked a loss before interest, taxes, depreciation and amortisation of 11.9 billion yen in the year ended March, compared to a loss of 43.2 billion yen a year earlier.
Persons:
SoftBank, SoftBank Group's, Kirk Boodry, Son, PayPay, Sam Nussey, Miho Uranaka, Scott Murdoch, David Dolan, Muralikumar
Organizations:
Companies, Z Holdings, PayPay, SoftBank Corp, Vision Fund, SoftBank, Syla Technologies, Rakuten Bank, SBI Sumishin, Bank, Astris Advisory, Mobile Marketing, Cambridge, Thomson
Locations:
. New York, Tokyo, New York, U.S, Astris Advisory Japan, Japan, England