Real Madrid and city rivals Atletico have been handed a transfer ban for breaching rules on signing foreign players under the age of 18.
The sanction, handed down by football’s world governing body FIFA, means the two clubs will not be able to register any new signings until July 2017 once the current transfer window closes at the end of the month.
If the clubs want to add to their ranks, then they will have to work quickly over the next fortnight – although the January transfer window rarely presents many high-profile possibilities.
The probe concerned players who participated in competitions with the clubs between 2007 and 2014 in the case of Atletico, and between 2005 and 2014 in the case of Real Madrid.
Both clubs are expected to appeal the ban.
Barcelona were handed a similar ban for breaching the transfer rules in 2014.