Why do football clubs keep transfer fees secret?

During the Premier League transfer window, clubs occasionally choose not to disclose the fees paid for players. Experts from BBC Sport’s 'Ask Us' team explain that this practice allows clubs to obscure their budget status and transfer strategies from rivals. In such scenarios, competing clubs remain unaware of how much of a buyer's budget has been spent, and selling clubs are not forced to reveal the funds available for securing replacements. In practice, however, many figures are eventually leaked via agents or other sources. For deals involving clubs listed on the stock exchange, hiding transfer fees can be more difficult. Clubs such as Lyon and Juventus may be required to disclose exact contract figures and variables to the stock market. Consequently, an English club might announce a deal as 'undisclosed', only for the foreign party to publish the precise amount. Under Premier League regulations, a 'homegrown' player is defined as someone who, regardless of nationality or age, has been registered with an English or Welsh club for at least three full seasons or 36 months before turning 21. This differs from UEFA rules, which only count the period between the ages of 15 and 21, whereas the Premier League starts from a younger age. Chelsea forward Joao Pedro is an example of this rule; born in Brazil, he joined Watford in January 2020 at age 18. Conversely, Eric Dier, despite being English and playing for the national team, was not considered homegrown because he completed his training in Portugal and spent less than three years at English clubs before turning 21. Noni Madueke is an inverse example; he played for PSV Eindhoven between the ages of 16 and 20, but retained homegrown status due to seven years spent in the Crystal Palace and Tottenham academies before moving to the Netherlands. Similarly, Jeremie Frimpong, despite being born in Amsterdam and playing for the Netherlands, qualifies as homegrown for Liverpool due to his nine-year tenure in the Manchester City academy from 2010 to 2019. Regarding sell-on clauses, if Team A sells a player to Team B for £5 million, and Team B later sells them to Team C for £20 million, the clause typically applies to the profit—in this case, £15 million. Therefore, a 10% sell-on clause would generate £1.5 million for Team A. These payments are usually made in line with the main transfer fee. If Team C pays the £20 million in four instalments, Team B typically pays the sell-on fee to Team A in four instalments as they receive them. However, the initial contract can mandate a full, upfront payment. Team A may also negotiate for immediate payment, though this often involves accepting a slightly lower total amount. BBC Sport published these explanations in their latest 'Ask Us' feature.