The offer comes from Japan Industrial Partners.
That's according to the Nikkei newspaper on Monday (November 7).
The proposal reportedly includes financial services group Orix Corp and utility Chubu Electric Power.
It comes just before a looming deadline for bids.
The report says no commitments from banks are included.
It says JIP aims to pull together the financing by the end of the month, if Toshiba accepts the bid.
Reuters has previously reported investor alarm over the fund's plan to keep on Toshiba's current management.
The Japanese conglomerate, which makes everything from chips to nuclear power stations, has lurched from crisis to crisis since 2015.
It's also been battered by discord between management and major shareholders, many of whom are foreign activists keen to see a buyout.
The outcome will have far-reaching implications for Toshiba's 116,000 employees.
Tokyo will also be watching for national security concerns, with the firm a major supplier of defense equipment.
There was no immediate comment on the Nikkei report from Toshiba.
