Toshiba, which is exploring strategic options, said this month it had received eight initial buyout proposals and two proposals for capital alliances that would see it remain listed.
The bidders are now discussing an offer price range of up to 7,000 yen a share with Toshiba's shareholders, the people said, representing up to a 27% premium to Toshiba's share price as of Wednesday's close.
A separate source said the range of offers had been wide spread and various conditions have been attached.
Toshiba said in a statement to Reuters that it would not disclose details of the proposals.
($1 = 136.1500 yen)
(Reporting by Makiko Yamazaki in Tokyo, Kane Wu and Scott Murdoch in Hong Kong; editing by Sumeet Chatterjee and Jason Neely)
By Makiko Yamazaki, Kane Wu and Scott Murdoch