On which amount is the solidarity contribution calculated?

The solidarity contribution is specifically calculated based on the transfer fee that is paid from one club to another. This fee represents a crucial aspect of a player's transfer because it is the amount that clubs negotiate for the right to transfer a player’s registration from one club to another.

The rationale behind this is to ensure that clubs that have contributed to the development of a player receive some financial benefit when that player is transferred to another club. This contribution is designed to support the youth system and acknowledge the investment made by the training clubs.

While the market value of a player, all payments related to the transfer, and the player's salary are important factors in the overall transaction, none of these directly determine the solidarity contribution. The solidarity contribution is solely based on the actual transfer fee that changes hands between the clubs involved in the transaction.