What are the rules on transfer window player swaps?

A rarely seen player swap deal has been agreed between Premier League clubs.

Everton winger Dwight McNeil is poised to join Crystal Palace, with Eagles forward Brennan Johnson going in the other direction to sign for the Toffees.

While such player trades between clubs are an unusual transfer window event, they are permitted - but they do have to meet certain rules.

The swap of McNeil and Johnson will technically be treated as two separate transfers, and will be part of the assessment of the Premier League squad cost ratio (SCR) regulations.

For example, Johnson cost Palace £35m, and his valuation as part of the McNeil deal would affect the Eagles' SCR calculations. He would need to be valued at about £30m for it to be recorded as a neutral transaction on the accounts.

But what if he is valued at less than that?

When McNeil's proposed move to Selhurst Park fell through in February, he was valued at £20m. If this is a true swap deal, and the two players are valued at £20m, that would be a £10m loss for Palace.

All swap deals also still have to pass the Premier League's fair market value (FMV) checks.

Regulations around associated party transactions (APTs) and FMV were first introduced in 2021 in order to "provide a robust mechanism to safeguard the financial stability, integrity and competitive balance" in the Premier League.

External valuation companies will be consulted on factors such as a player's age and performance level, as well as assessing deals with other comparable players, to determine if a deal tallies with market value.

The Premier League will make the final judgement on whether the deal passes FMV checks.

Thanks to Alec in Wales for the question.

This article is the latest from BBC Sport's Ask Me Anything team.