Stable Union Deed vs Prenuptial Agreement: Key Differences
Understand the differences between a stable union deed and a prenuptial agreement, choosing a property regime, and their effects at the real estate registry.
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Por CartorIA Team — AI-assisted legal writing · 5º Tabelionato de Notas de Recife
Context note: This content describes Brazilian notary and registry law.
This article answers
- What is the difference between a stable union deed and a prenuptial agreement?
- How does choosing a marital property regime work in a stable union and in a marriage?
- When is it necessary to execute a stable union deed or a prenuptial agreement?
- In the conversion of a stable union into marriage, do the effects of the property regime retroact?
- How much does it cost and where can you execute a stable union deed or a prenuptial agreement?
In summary
- A stable union public deed declares an existing factual situation and establishes the property management rules of the cohabitants.
- A prenuptial agreement is a preventive public deed executed before civil marriage to adopt a property regime other than the legal default.
- Both the stable union deed and prenuptial agreement require execution at a tabelionato de notas (notary public office) to guarantee public notice and legal authenticity Lei nº 10.406/2002 — Código Civil, art. 215.
- Both instruments generate effects against third parties only after proper registration with the competent bodies, such as the Registro de Imóveis (Real Estate Registry) and the Registro Civil das Pessoas Naturais (Civil Registry of Natural Persons).
What is the difference between a stable union deed and a prenuptial agreement?
The main difference between a stable union deed and prenuptial agreement lies in the legal nature and the moment of application of each notary act. A stable union is an existing factual situation. It is characterized by a public, continuous, and lasting cohabitation established with the goal of constituting a family. By executing the public deed at the tabelionato de notas (notary public office) Lei nº 8.935/1994, art. 6º, the couple legally formalizes this existing factual status and establishes the couple's property management rules.
On the other hand, a prenuptial agreement is a solemn family law contract executed before civil marriage. It has a conditional nature. This means that the prenuptial agreement only produces legal effects if the civil marriage actually takes place. If the marriage does not occur, the agreement does not come into effect.
Furthermore, the destination of the acts within the public registry system differs. The stable union deed can be submitted to the registro de imóveis (real estate registry) to ensure enforceability against third parties regarding the couple's real estate assets. The prenuptial agreement, in turn, must be presented to the registro civil das pessoas naturais (civil registry of natural persons) during the marriage licensing procedure and, after the ceremony, registered at the Cartório de Registro de Imóveis (Real Estate Registry Office) of the spouses' domicile to be effective against third parties.
The choice between a stable union deed and prenuptial agreement depends directly on the civil status and family goals of the couple. Cohabitants who do not intend to marry under civil law use the stable union deed. Individuals who intend to enter into a civil marriage and wish to opt out of the default regime choose a prenuptial agreement.
You can consult our guide on stable union at the notary office to understand the cohabitation requirements in detail.
How does choosing a marital property regime work in a stable union and in a marriage?
Choosing property rules in a stable union deed and prenuptial agreement allows partners to define how wealth acquired before and during their life together will be managed, divided, or preserved.
In a stable union formalized by public deed, cohabitants can choose different property regimes, such as:
- Partial community of property (comunhão parcial de bens): shared ownership of assets acquired for value during the union.
- Total separation of property (separação total de bens): completely distinct individual assets, with no sharing of past or future property.
- Universal community of property (comunhão universal de bens): unification of all present and future assets of the cohabitants.
- Final participation in acquests (participação final nos aquestos): each cohabitant maintains their own estate during the union, but shares assets acquired for value upon dissolution.
> Regulatory note on the default regime: The Código Civil (Civil Code) provides that, in the absence of explicit agreement between the parties regarding property rules, the partial community of property regime applies to both stable unions and marriages. However, the specific text of the Civil Code article regarding the default regime is not included in the normative portfolio attached to this dossier. A formal gap in direct citation of the corresponding article is declared, maintaining the legal foundation in the general norms for notary services under Lei nº 8.935/1994 (Law No. 8,935/1994 — Brazilian Notary and Registry Act) Lei nº 8.935/1994, art. 1º.
In civil marriage, the procedure for establishing the regime is tied to the marriage licensing process. If the prospective spouses choose the legal default regime of partial community of property, executing a prenuptial agreement is not required. The choice is declared directly before the oficial de registro civil das pessoas naturais (civil registry officer).
However, if the prospective spouses choose any other regime—such as total separation of property or universal community—the law requires the prior execution of a public deed of prenuptial agreement at a tabelionato de notas. Without this public deed, choosing a different regime is void Lei nº 10.406/2002 — Código Civil, art. 166.
Compliance supervision of these normative requirements by extrajudicial service offices is guided by the directives of the state Corregedorias de Justiça (Internal Affairs Offices of Justice) and by the national rules of the Conselho Nacional de Justiça (National Justice Council — CNJ) in Provimento CNJ nº 149/2023 (CNJ Ordinance No. 149/2023) Provimento CNJ nº 149/2023, Livro II. The Corregedoria-Geral de Justiça inspects the conformity of acts executed by notary publics to ensure that property stipulations comply with current legislation.
Comparative chart of notary property acts
The following table provides a structured comparison between the two legal instruments to help you select the appropriate act:
| Comparison Criterion | Stable Union Public Deed | Prenuptial Agreement |
| :--- | :--- | :--- |
| Primary purpose | Formalize factual cohabitation and establish property regime | Establish property regime for a future civil marriage |
| Execution moment | During or after the start of cohabitation | Before the civil marriage ceremony |
| Legal effectiveness | Immediate upon signature of the deed | Conditioned upon the celebration of civil marriage |
| Executing office | Tabelionato de Notas (Notary Public Office) | Tabelionato de Notas (Notary Public Office) |
| Mandatory secondary registration | Registro de Imóveis (for real estate assets) | Registro Civil das Pessoas Naturais and Registro de Imóveis |
| Attorney requirement | Optional for standard administrative procedures | Optional for standard administrative procedures |
| Nature of relationship | Formalized factual union | Solemn civil marriage |
FAQ
What is the difference between a stable union deed and a prenuptial agreement?
A public deed of stable union formalizes an existing cohabitation between two people and sets immediate property rules. A prenuptial agreement, on the other hand, is a solemn contract executed prior to marriage whose effectiveness is conditioned upon the future civil marriage ceremony.
How does choosing a marital property regime work in a stable union and in a marriage?
In a stable union, cohabitants define their property regime directly in the public deed of stable union at a notary public office. In marriage, if the prospective spouses desire a regime other than partial community of property, they must execute a prenuptial agreement prior to marriage licensing at the civil registry of natural persons.
When is it necessary to execute a stable union deed or a prenuptial agreement?
A stable union deed is recommended for cohabiting couples who want to formally declare their relationship, establish its start date, and choose a property regime. A prenuptial agreement is mandatory for prospective spouses intending to marry under total separation, universal community, or final participation in acquests.
In the conversion of a stable union into marriage, do the effects of the property regime retroact?
Cohabitants may agree to maintain or modify their regime upon conversion. However, altering the property regime for a past period requires judicial authorization or strict compliance with Provimento CNJ nº 149/2023 guidelines to protect third-party rights.
How much does it cost and where can you execute a stable union deed or a prenuptial agreement?
Both acts are executed at any notary public office (tabelionato de notas) chosen by the parties. Fee amounts are fixed by state law and depend on the official table in effect in the state where the deed is formalized.
Base legal
- provimento_cnj 149 2023 — Provimento CNJ nº 149/2023
- lei_federal 10.406 2002 — Lei nº 10.406/2002
- codigo 10.406 2002 — Lei nº 10.406/2002 — Código Civil
- lei_federal 8.935 1994 — Lei nº 8.935/1994
- codigo 10.406 2002 — Lei nº 10.406/2002 — Código Civil
- codigo 10.406 2002 — Lei nº 10.406/2002 — Código Civil
- lei_federal 14.382 2022 — Lei nº 14.382/2022
- lei_federal 8.935 1994 — Lei nº 8.935/1994