Not much of a present for banks but home owners were full of Christmas cheer.
Spanish lenders have been told they must repay customers more than 4 billion euros.
Europe's top court has unexpectedly overturned a Spanish ruling that capped liabilities relating to a disputed mortgage clause.
(SOUNDBITE) (Spanish) LAWYER FOR THE MORTGAGE VICTIMS PLATFORM (PAH), ALEJANDRA JACINTO, SAYING:
"We are here today to celebrate this victory and to tell the supreme court to take note because European institutions once again have had to step in to safeguard our rights."
Banks must compensate customers for what they lost before May 2013 - that's when Spain's Supreme Court declared the liabilities invalid if not presented clearly.
The new charges could eat into bank earnings, which have already been eroded by record low interest rates and fierce competition.
More mergers could be the result with Banco Popular seen as a potential takeover target.
It's facing around 330 million euros in new charges and its shares dropped almost 7 percent.
Banco Sabadell, Caixabank, BBVA and Liberbank were also hit - the latter two predicting extra costs between them of almost 2 billion euros.
The court said the ruling was final and could not be appealed.
One consumer lobby group also thinks it could open the door to 2 million others seeking repayments from banks.