A common misconception in Australia is that a financial agreement must be in place before a couple walks down the aisle. The reality is more flexible. Under the Family Law Act 1975 (Cth), married couples can enter into a binding financial agreement (BFA) at any point during their marriage, not just before it begins. These post-marriage agreements are sometimes called "post-nuptial agreements" or simply "during-marriage BFAs," and they carry the same legal weight as any agreement signed beforehand.
What is a post-marriage BFA?
A post-marriage BFA is a written agreement between two married people that sets out how their property, assets, and financial resources will be dealt with if the relationship breaks down. It can also address financial support (spousal maintenance) arrangements. The agreement effectively opts the couple out of the standard property settlement process that would otherwise apply under family law, provided the agreement meets all the legal requirements to be enforceable.
The legal basis for these agreements sits in section 90C of the Family Law Act, which specifically provides for financial agreements made during a marriage. This is distinct from section 90B, which covers pre-marriage agreements. Both types are referred to colloquially as "prenups," though technically a prenup refers only to a pre-marriage arrangement. Understanding the difference between a prenup and a binding financial agreement can help you identify which instrument applies to your situation.
Why would a married couple want a BFA?
There are many reasons a couple might decide to formalise their financial arrangements after the wedding. Some of the most common include:
- A change in financial circumstances. One spouse may receive a significant inheritance, start a business, or come into assets that were not part of the picture at the time of the marriage.
- Protecting a family business. If a spouse becomes involved in a family enterprise during the marriage, a BFA can clarify what share of that business belongs to whom in the event of separation.
- Blended families. Couples who married without a pre-marriage agreement may later want to protect assets intended for children from a prior relationship.
- Relationship concerns. Sometimes a couple going through a rough patch wants to have clarity around financial matters without necessarily separating. A BFA can provide that structure.
- The couple simply forgot or ran out of time before the wedding. A post-marriage BFA gives them the chance to put that protection in place without it being too late.
Does a post-marriage BFA work the same way as a prenup?
In most respects, yes. The content of the agreement, and the rules around what it can and cannot cover, are largely the same. Both types of agreement can deal with property owned at the time of signing, property acquired in the future, superannuation, and financial support. Both can also be set aside by a court if certain grounds are met, such as fraud, duress, unconscionable conduct, or a material change in circumstances relating to the care of a child.
The process for creating the agreement is also the same. Each party must receive independent legal advice from a separate lawyer before signing. The lawyer for each party must sign a certificate confirming that advice was given. Without those certificates, the agreement cannot be enforced. If you are thinking about entering a BFA of any kind, understanding what makes a binding financial agreement enforceable is the most important place to start.
What a post-marriage BFA cannot do
There are limits to what any BFA can cover, regardless of when it is signed. An agreement cannot deal with parenting arrangements or child custody. Courts retain the power to make parenting orders independently of any financial agreement, and no BFA can pre-determine outcomes for children. Similarly, an agreement that attempts to deprive a party of a reasonable level of financial support where they would otherwise be eligible for it may face scrutiny.
A BFA also cannot override a court's discretion entirely in cases involving unconscionable conduct. If one spouse pressured the other into signing, or if the terms were grossly unfair at the time of signing, a court can set the agreement aside.
Timing and practical considerations
While there is no deadline for signing a post-marriage BFA, the further into a marriage a couple gets, the more complex the financial landscape tends to become. Joint assets accumulate, superannuation grows, and the lines between what each person brought in and what was acquired together can blur. This does not make a BFA impossible, but it does make a thorough and accurate asset disclosure more important.
Both parties are required to make full and honest financial disclosure before and during the drafting process. If either party conceals assets or provides misleading information, the agreement can be challenged later on those grounds. This is one reason why getting experienced legal advice early matters, even if you have been married for years before deciding to put an agreement in place.
It is also worth noting that separation itself changes the type of agreement available. Once a couple has separated, a different section of the Family Law Act applies (section 90D for agreements after separation but before divorce, and section 90E for agreements after divorce). These are distinct instruments with their own requirements, which is why the timing of when you seek advice is significant.
Getting started
If you and your spouse want to put a financial agreement in place now, the process begins with each of you engaging a separate family lawyer. Your lawyer will work with you to identify the assets and liabilities to be covered, draft the agreement to reflect your intentions, and provide the independent legal advice required before you sign. Your spouse's lawyer does the same. Once both parties have signed and both legal certificates are attached, the agreement is complete.
There is no court filing required for a BFA to take effect, which keeps the process relatively private. However, if the agreement is ever challenged, a court will examine every aspect of how it was prepared and signed. That scrutiny is exactly why the quality of the legal advice you receive matters so much from the outset.
Whether you missed the window before your wedding or your financial circumstances have simply changed, a post-marriage BFA can still give both of you clarity and protection. Speaking with a family lawyer sooner rather than later gives you the best chance of putting something in place that will hold up if it is ever needed.