How do add-ons work in football transfers?

Fonte · BBC Sport Football

Published Many of this summer's transfer window deals have been stated as a base fee plus 'add-ons'. For example, Rayo Vallecano's Pep Chavarria has joined Chelsea in a five-year deal worth about £16.3m - plus a further £1.7m in add-ons. These payments are often complex and usual