Manchester United have been asked for reassurances that the club's money will not be used to pay off the Glazer family's expensive PIK loans.
Investment analyst Andy Green, whose investigation into the Glazers' US businesses formed the basis for Tuesday night's BBC Panorama programme into United's finances, believes the Glazers have no option but to spend club funds to pay off the PIK debt which totals Â£220million.
The PIKs will carry a 16.25% interest rate from August, and unless any payments are made these loans will spiral to Â£600million by 2017, claims Green.
In an open letter to United's chief executive David Gill, Green says: "I have no doubt you will have seen the new research about the state of the Glazer family's US real estate business. I am also sure that the parlous financial state and weak cash generation of the business will have been as much of a surprise to you as it was to me.
"The family's spokesman has. stated that the club will not be sold, meaning the Glazer family need to repay their PIKS. Given the evidence now in the public domain about the profitability and levels of debt in the Glazer family's other businesses and hence the family's inability to pay off the PIKs from their own resources, it seems the only possible source of cash to do so is Manchester United itself.
"In light of these revelations, can you assure United supporters that none of club's current or future cash will be used to repay the Glazer family's PIKs?"
Panorama said the Glazer family's debts total more than Â£1.1billion - Â£700million tied to Manchester United, Â£388million on mortgages for their First Allied shopping mall business in the USA and Â£66million tied to their Tampa Bay Buccaneers NFL team.
The Glazers say they are comfortable with the situation and that their assets total Â£2billion.
Gill has previously said the PIKs are nothing to do with the club and are solely the concern of the Glazers.
Gill said in January: "That is something that the family, the owners, have put in place and they will ensure is repaid or is part of their overall financial planning in due course, but that is nothing to do with the club."