These are agreements entered into before or after marriage for the purpose of establishing, modifying or replacing the matrimonial property regime, or of including any other provisions in connection with the marriage.
To be valid, matrimonial property agreements must be executed in a notarial authentic instrument.
A matrimonial property regime is the body of rules governing the financial relations between the spouses and also their relations with third parties.
Without prejudice to other possible arrangements, two basic models may be distinguished:
A separation of property model, characterised by the absence of a common estate or pool of assets, in which property belongs separately to each spouse, either because it was already owned by that spouse when the regime began or because it is acquired by that spouse while the regime is in force.
And a community property model, in which, alongside the separate estates of each spouse, there is a common estate comprising, to a greater or lesser extent depending on the regime in question, property acquired during the marriage.
In the absence of an agreement between the spouses, the applicable law determines their matrimonial property regime.
Under the Civil Code, the default statutory regime is the community of property regime known as sociedad de gananciales. Other community property regimes include the Aragonese consorcio conyugal and the Navarrese sociedad conyugal de conquistas.
In the Basque Country, the general rule, in the absence of a matrimonial property agreement, is likewise the sociedad de gananciales regime governed by the Civil Code, although in certain cases linked to local civil citizenship (vecindad civil) in the Tierra Llana of Bizkaia, Aramaio or Llodio, the comunicación foral de bienes, or foral community of property regime, applies.
By contrast, in Catalonia and the Balearic Islands the default statutory regime is separation of property.