Short answer. Article 131 of the Family Code has each marriage's capital, fruits, and income determined by the applicable rules of evidence when the liquidations are carried out at the same time. Where it is genuinely unclear which partnership a property belongs to, it is divided between the partnerships in proportion to each one's capital and duration.
What the law says
Whenever the liquidation of the conjugal partnership properties of two or more marriages contracted by the same person before the effectivity of this Code is carried out simultaneously, the respective capital, fruits and income of each partnership shall be determined upon such proof as may be considered according to the rules of evidence.
Family Code, Article 131 — Simultaneous Liquidation of Two or More Marriages. Read the full provision →
What the law says
In case of doubt as to which partnership the existing properties belong, the same shall be divided between the different partnerships in proportion to the capital and duration of each.
Family Code, Article 131 — Simultaneous Liquidation of Two or More Marriages. Read the full provision →
This article addresses a specific, narrow situation
Article 131 applies where one person contracted two or more marriages before the effectivity of this Code, and the conjugal partnerships from those marriages are being liquidated simultaneously. Both conditions matter: the marriages have to predate the Family Code, and the liquidation of more than one of them has to be happening at the same time, rather than one estate being settled long after another has already been closed.
The first step: determine what belongs to which partnership
Where that simultaneous liquidation is happening, the article's approach is to have the capital, fruits, and income of each partnership determined separately, based on whatever proof is available and considered according to the ordinary rules of evidence. This is a fact-finding exercise before any division formula comes into play — the goal is to trace which assets, and which income from those assets, actually trace back to which marriage's partnership.
When that tracing genuinely cannot be done
The article anticipates that tracing will not always be possible. Where there is real doubt as to which partnership an existing property belongs to, the fallback rule applies: the property is divided between the partnerships in proportion to the capital and duration of each. A partnership that existed longer, or that started with more capital, receives a proportionately larger share of the doubtful property under this formula, rather than the doubtful property being split evenly by default.
Why this takes careful documentation
Given that the article relies on proof and the ordinary rules of evidence before falling back to a proportional formula, records of when each marriage began, what capital each partnership started with, and what property and income can be traced to each are central to how this actually plays out. This is a fact-heavy process rather than a simple mechanical split, and it is worth working through with a lawyer familiar with liquidating multiple conjugal partnerships together.