Short answer. When doubt exists about which of two pre-Family Code marriages owns a property during simultaneous liquidation, Article 104 of the Family Code directs that the disputed property be divided between the two communities in proportion to each community's capital and the duration of each marriage.
What the law says
In case of doubt as to which community the existing properties belong, the same shall be divided between the different communities in proportion to the capital and duration of each.
Family Code, Article 104 — Overlapping Communities from Multiple Marriages. Read the full provision →
When this rule applies
Article 104 of the Family Code addresses a narrow but real situation: a person contracted two or more marriages before the Family Code took effect, and those marriages are now being liquidated at the same time. Each marriage had its own community property. The task is to sort the properties into their respective communities — but sometimes the records are incomplete or the property was acquired in a way that makes its attribution genuinely unclear. Article 104 provides the framework for resolving that doubt.
Start with proof: each community is identified by evidence
The first step is evidentiary. Article 104 says the respective capital, fruits, and income of each community shall be determined by whatever proof may be considered under the rules of evidence. This means documents, testimony, records of acquisition, receipts, titles, and anything else that traces property to one marriage rather than the other. You are not forced immediately to split everything down the middle — the law expects the parties or the court to work through the available evidence first and attribute property to the right community where that attribution can be proven.
The doubt rule: proportion by capital and duration
Where evidence is insufficient and genuine doubt remains about which community owns a specific property, Article 104 provides a tiebreaker: divide it between the communities in proportion to the capital and duration of each. Capital refers to the assets each community brought in at the start. Duration refers to how long each marriage lasted. A longer marriage that started with more capital would receive a proportionally larger share of disputed assets. This is a fairness mechanism — it avoids an all-or-nothing result when the truth cannot be determined from the record.
What this means in practice
If you are navigating the liquidation of two pre-Code marriages — whether as a surviving spouse, an heir, or a party to the liquidation — the practical work is gathering records that connect specific properties to specific marriages. Bank passbooks, land titles, deeds, tax declarations, and any contemporaneous documentation of when and how properties were acquired are all useful. The cleaner the paper trail, the more that can be attributed without resort to the doubt-proportion rule. Where gaps exist, the proportional division formula will fill them. A lawyer can help you map the assets against the available evidence and apply the appropriate rule to each disputed item.