Sale Sharks owner Brian Kennedy has been told his revised offer for Rangers is unacceptable.
Kennedy informed administrators Duff and Phelps of his new bid on Wednesday, two weeks after the deadline for best and final offers.
But a spokesman for Duff and Phelps said: "The administrators haven't received a revised written offer and have informed Brian Kennedy his best verbal offer is not capable of acceptance."
Kennedy claimed he had doubled his first offer to a "double digit million pound bid" on Wednesday night and implored administrators to act swiftly. They have done so with regards his offer but there remains no decision on a preferred bidder.
In a statement, joint administrator David Whitehouse added: "We have had a series of constructive discussions with bidders.
"We have made it crystal clear to them all that to announce a preferred bidder we need definitive, unconditional bids on the table.
"It is also important to let fans know that at this stage there is a world of difference between people indicating their intentions - even though they are well meaning - and putting them in black and white.
"We understand there are complex issues for bidders to deal with and we do not doubt that all parties want to attain control of the football club.
"We understand also that those interested in buying the club are working hard to resolve all outstanding issues.
"We are continuing to make representations to all stakeholder groups - including the football authorities - to give clarity on outstanding issues which will help existing bids move to unconditional status."