Up to half of the locally-trained players must be from the club itself, with the others being either from the club itself or from other clubs in the same association.
UEFA defines locally-trained or 'homegrown' players as those who, regardless of their nationality, have been trained by their club or by another club in the same national association for at least three years between the age of 15 and 21. Up to half of the locally-trained players must be from the club itself, with the others being either from the club itself or from other clubs in the same association.