Sheffield Wednesday owner Dejphon Chansiri is securing a debt against Hillsborough Stadium, according to documents seen by BBC Radio Sheffield.
A pending charge against the stadium - a legal way of securing a loan - was lodged with the Land Registry on 30 September.
It means the Owls' ground, which was bought by Chansiri for £60m to try to ensure the Championship club did not breach spending rules, is at risk of being sold if repayments are not kept.
The inclusion of the profits in Wednesday's 2017-18 accounts, despite the ground being sold a year later, led to the club being deducted 12 points for the 2020-21 season.
An independent disciplinary panel found that the club were guilty of an historic breach of the Championship's profitability and sustainability rules.
Wednesday have signalled their intention to appeal against the ruling.
What's happening at Wednesday?
Hillsborough is owned by Sheffield 3 Limited, a company controlled by Wednesday chairman Chansiri.
Chansiri agreed to pay £60m for Hillsborough, with the club's 2017-18 accounts showing that an initial payment of £7.5m was due within one year. The 2018-19 accounts are now two months overdue at Companies House.
The pending charge has been registered by New Avenue Projects Limited, a company which has previously acted as an intermediary, matching clubs who need finance with lenders, and taking a commission on the deal.
It means financing of the loan may involve an unknown third party, which could be an individual or a financial institution.
New Avenue Projects Limited is owned and run by Nigel Weiss, a former city finance lawyer.
When asked about the nature of the charge placed on Hillsborough, Weiss and Sheffield Wednesday declined to comment.
Change in strategy
Up to 2018 Chansiri had supported the Owls with loans totalling over £77m.
Dr Dan Plumley, a sports finance expert at Sheffield Hallam University, told BBC Radio Sheffield the debt marks a shift in approach.
He said: "The owner has already pumped in a significant amount of money over the years, why is it not the case that he can just do the same again?"
Whilst Dr Plumley says the debt might not be a serious issue now, there could be "alarm bells" in the future.
He added: "What if the owner wishes to sell in the future? What if he walks away? What if he hasn't got the funds? What happens if Sheffield Wednesday drop down to the next division with the points deduction?"
The Sheffield Wednesday Supporters' Trust have called on the club to provide clarity.
James Silverwood, the group's interim director, said the news was a "worrying direction of travel".
"If this is nothing to worry about just explain to us why it's nothing to worry about," he said.
Other financial questions
The Owls' accounts for the 2018-19 season are expected to show a fall in the club's wage bill.
Wednesday have also significantly reduced spending on player transfers since the start of 2018.
Events off the pitch have also suggested issues with cash flow.
In January the Owls launched a 10-year season ticket, while early-bird season tickets for the 2020-21 campaign were put on sale in the same month with a purchase deadline set of 10 February.
In June it emerged some of the club's players had not been paid in full, but the matter was later resolved.
Wednesday also furloughed a significant number of staff during lockdown earlier this year. Salaries were topped up to 100% by the club.
Football clubs across the English Football League are struggling with coronavirus restrictions that have forced stadiums to remain closed.
The EFL has estimated the impact across its three divisions of a full season without fans to be around £250m.