Leeds United's shirt sponsor has filed a winding-up petition against the club over an alleged unpaid debt.
Andrew Flowers, managing director of shirt sponsors Enterprise Insurance, was part of the Sport Capital consortium whose attempt to take over the club collapsed last week.
Italian Massimo Cellino has since agreed to buy a 75% stake in the club, subject to the deal being approved.
Owners GFH said the club had "always met its financial obligations".
The case will be heard in the High Court in March.
In 2012, Leeds borrowed £1.7m from Gibraltar-based Enterprise Insurance at 7% interest for repayment in 2015.
The Financial Times reports that the petition was filed on 29 January, the day after Sport Capital's bid fell through.
Cagliari owner Cellino, 57, agreed a deal with current owners GFH on Friday but it is yet to be approved by the Football League.
Cellino's lawyer, Chris Farnell, promptly told manager Brian McDermott that he had been relieved of his duties, on the same day.
The former Reading manager was then reinstated within 24 hours, with GFH claiming it was still in ownership and control of the club.
It is believed that the Sport Capital and Together Leeds consortiums have now teamed up to buy the club, dismissing Cellino's bid and promising to match his offer.
They were due to meet with GFH for talks on Tuesday, believing Cellino's ownership would not be in the club's best interests.
A proposed takeover by Sports Capital, which involves Flowers and Leeds managing director David Haigh, fell through last week because of a lack of financial backing.
In a statement, owners GFH said: "The winding-up petition issued by Enterprise Insurance, a sponsor whose managing director, Andrew Flowers, claims to support the club, is misconceived and an abuse of legal process. It is being vigorously contested by the club's lawyers and there are no valid grounds to issue the petition.
"Under the ownership of GFH Capital, Leeds United has always met its financial obligations, and it will continue to do so."
GFH has previously insisted that the mid-table Championship club will not go into administration while it is in charge.