Chelsea and Aston Villa have reportedly been warned by UEFA that player swap deals will be monitored closely to make sure fees have not been inflated.
UEFA are believed to have taken issue with at least one previous deal, according to The Times.
In recent years Premier League clubs have paid sizeable fees to each other in instances where players have moved in each direction.
And there have been protests from rivals that this has been done with the aim of artificially increasing transfer income in order to comply with Profitability and Sustainability Rules.
Earlier this month it was revealed that UEFA had stepped in to knock down the value of at least one deal that involved the two clubs.
The Blues have been hit with a €31million (£26.8m) fine for breaching UEFA’s financial rules.
Chelsea have been warned by UEFA that player swap deals will be monitored closely
Aston Villa have also been made aware that any such deals will be put under the microscope
That figure could potentially rise to a record-breaking €91m (£78.5m) if they fail to comply within the next four years amid the threat of further sanctions hanging over them.
Aston Villa were also fined €11m (£9.5m), which could rise to €26 million (£22.4m).
UEFA stated at the time that they had looked at ‘transactions involving the exchange of players’ and that those ‘required specific adjustments to the club’s financial result’.
The Times add that that UEFA will continue to scrutinise all such swap deals but Chelsea and Villa will be particularly under the microscope following their settlements.
Omari Kellyman joined Chelsea from Villa for £19m last summer but is yet to make an appearance for the club.
Ian Maatsen, a product of the Chelsea academy, went the other way for £37.5m and went on to play 29 times for the club in the top flight last term.
Both clubs have agreed that they will be excluded from European competition for a season should they breach the settlement.
