All of the clubs involved, of which there are understood to be fewer than 20, have been offered settlements from UEFA's club financial control board.
That offer, which would include sanctions for breaking the rules, will either be accepted by the clubs or negotiated as they look to come to terms on a less severe punishment.
It is not known what sanctions have been proposed to the clubs involved, although the threat of being excluded from European competition is not thought to have been used on this occasion.
Other potential punishments that could be imposed by UEFA include a reprimand, a fine and restrictions being placed on a club's squad for European competition next season.
If no agreement is reached between the two parties then the outstanding cases will go to an adjudicatory panel to be decided upon.