Sheffield Wednesday have been issued with a winding-up petition by Her Majesty's Revenue and Customs, the club have said in a statement.
The action by HMRC relates to an outstanding PAYE balance of £550,000 and the club say the petition will be heard in the High Court on August 11.
However, Wednesday have sought to reassure their fans that the club is "not about to be wound up, nor is it about to enter into administration".
The statement added: "We have been involved in dialogue with HMRC for a number of weeks.
"As such we have been somewhat surprised and disappointed by their decision to seek a winding-up order at this time.
"We understand that HMRC is taking a tougher line in general with football clubs, but feel their actions are disproportionate and will raise unnecessary speculation as to the financial position of the club.
"We can inform supporters that the club, working in partnership with the Co-operative Bank and their advisors, will seek to settle this matter as soon as is practical.
"Furthermore, during a period of change this summer the bank has been an integral partner for Sheffield Wednesday.
"We will continue to work together to create the best environment possible for the club to move forward, including ongoing dialogue with potential investors that will seek to secure the long-term financial health of the club."
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