Investment firm Redbus and property developer Simon Morris have submitted a joint bid to buy Leeds United.
Redbus chairman Simon Franks said they had made an offer despite "impediments" being put in their way by the process.
Ex-Hull owner Adam Pearson is believed to have also put in a bid by the 1700 BST Monday deadline and United chairman Ken Bates' offer is still on the table.
Administrators put the club up for sale on Friday and Bates plans to take legal action if it is sold to a rival bidder.
He re-submitted his offer after a legal challenge was made by HM Revenue and Customs (HMRC) over his original takeover plans.
The 75-year-old said: "Our bid is the original deal that was done in the meeting of creditors when we placed the Company Voluntary Agreement (CVA) on1 June.
"We have amended it twice to try to meet the Inland Revenue's objections and now we have withdrawn the conditionality of it, so it's now unconditional.
"We believe in fact our offer is valid. Therefore it should be the only one to be accepted."
Leeds have debts of £35m, including the money owed to HMRC in unpaid taxes, and Bates had proposed to take the club out of administration by repaying creditors eight pence in every pound that it owed.
Franks claims only Bates has been allowed full access to the club's accounts in recent months.
"I'm furious. This is utterly prejudicial. We have to reduce our bids because of the 'known unknowns'. Mr Bates doesn't have to," Franks said.
"We don't know what we are bidding for."
Pearson, who left Hull in June after selling the club to a consortium fronted by Paul Duffen for £10m, is expected to make a formal approach along with Internet guru Peter Wilkinson.
Duncan Revie, son of former Leeds manager Don, has also previously declared an interest in buying the Yorkshire club.