5) Everton (-€242m)
Under Farhad Moshiri, the Toffees were notoriously profligate with their spending.
Some of the highest-profile failures during Moshiri’s time as owner include the likes of Cenk Tosun (£27m), Davy Klaassen (£25m) and Jean-Philippe Gbamin (£25m).
The club failed to get any money back from Tosin and Gbamin, who both eventually left on free transfers, while they received £12m for Klaassen.
Fans of the Merseyside club will hope that the Friedkin Group are much wiser when it comes to signing new players.