A club announces a £100m signing. The number in the accounts that year is £20m. Nobody has lied.
Amortisation is the reason, and it is the single accounting concept that explains more about the modern transfer market than any other.
The mechanic
A transfer fee buys a contract, and accounting treats that contract as an asset that wears out over its life. So the fee is spread evenly across the contract's length rather than charged in the year it is paid.
A £100m fee on a five-year contract is £20m a year of amortisation for five years. The same £100m on an eight-year contract is £12.5m a year for eight.
Two things follow, and both matter.
The first is that the cash and the accounting are different things. A club may pay the £100m in instalments over three years while charging £20m a year for five. Neither figure is the other one's shadow.
The second is that a longer contract lowers the annual cost. That is not a trick. It is the direct consequence of spreading the same number across more years, and it is why contract length became a financial instrument rather than a statement about a player.
What Chelsea worked out
Profit and sustainability rules limit what a club may lose over a rolling period. Losses are calculated from the accounts, and the accounts carry amortisation, not the cheque.
So a club signing heavily could reduce the annual charge by handing out unusually long contracts. Chelsea signed players on deals reported at up to eight years, per The Guardian's account of the loophole. Eight years instead of five turns £12.5m a year into the reported cost of a £100m player.
It was legal. It was also plainly not what the rule intended, since a club could keep buying while the measured cost of buying fell.
The five-year cap
UEFA closed it in June 2023, capping amortisation at five years regardless of contract length. Premier League clubs then voted to amend their own rules to match, per Sky Sports.
The mechanic now: a club may still sign a player on a seven or eight-year contract where the national association permits it, but the fee must be written down over the first five years. The long contract keeps its use for controlling the player's registration. It no longer reduces the annual charge.
The change was not backdated, so the existing long deals kept their treatment.
Worked example, this summer
Manchester United signed Andrey Santos and Youri Tielemans for a combined £85m, per Sky Sports and ESPN.
Assume, for arithmetic rather than as a claim about either contract, five-year deals. That is £17m a year of amortisation across the two, every year, for five years, before a penny of wages.
Wages are the part people forget. Wages are not amortised. A salary is an expense in the year it is paid, in full. So the annual cost of a signing is the amortisation charge plus the whole wage, which is why a free transfer is never free. Karl Darlow arrived at Manchester United on a free from Leeds United this summer, per Sky Sports: no fee, no amortisation, and a full wage in the accounts from day one.
Why this shapes what you see
Three visible behaviours fall straight out of the maths.
Selling academy players is disproportionately valuable. A player who cost nothing has no amortisation left to write off, so the whole fee lands as profit. That is why clubs facing a compliance problem sell a homegrown 21-year-old rather than an expensive 29-year-old.
A player sold below his fee can still hurt. If a club paid £60m and has amortised £24m of it, the book value is £36m. Sell at £30m and the accounts take a £6m loss even though the headline reads like a partial recovery.
Add-ons are quietly attractive. Carlos Baleba's move to Manchester United was reported by Fabrizio Romano as £65m plus £5m in add-ons and by David Ornstein as £70m including bonuses. Contingent money that has not been triggered is not yet a cost. Structure is a financial choice, not only a negotiating one.
The one-line version
Amortisation is why the fee you read and the cost a club carries are different numbers, and why the second one is the one that governs what the club can do next.
Sources: Sky Sports, on the Premier League vote to cap amortisation at five years; The Guardian, on UEFA closing the long-contract loophole in June 2023; Sky Sports and ESPN, 13 August 2026, on the combined £85m for Andrey Santos and Youri Tielemans and on Karl Darlow's free transfer; Fabrizio Romano and David Ornstein, 21 August 2026, on the structure of the Carlos Baleba fee.