What happens when a couple wants to have an unfair prenup?

Question

This question is prompted by a recent one on the topic of prenuptial agreements.

Imagine that Joe and Mary decide on a prenup that states that in case of a divorce Joe gets 90% and Mary 10% of the estate. This split is arguably "unfair" to Mary.

Do they have to state the reasons for such a split? Can such a split exist at all?

There may be many reasons for them wanting to do that: Mary is much more likely to succeed in business, she is an order of magnitude smarter and knows she will win at the lottery, Joe is sick and will need way more support than Mary, ...

Some of these reasons are reasonable, some are silly - but these are their decisions and we assume that both are sane.

To reiterate the introduction questions above:

• can a split be arbitrary despite the "fairness" requirement?
• does the "fairness" need to be explained in the prenup?

The original question was for the US so for the sake of continuity I will tag it as US, but would be interested in France as well.

Answer 1

canada

You have clarified in a comment that your single question is whether an explanation of fairness is needed in a spousal agreement.

Fairness need not be explained in the agreement itself. Neither the federal Divorce Act nor any of the provinces' Family Law Acts require a spousal agreement to explain its fairness in the agreement itself.

Rather, if an agreement is contested, the court will consider evidence about:

• the making of the agreement,
• the circumstances of the parties at the time of the agreement, throughout the spousehood, and at separation

The court assesses whether the process or substance of the agreement rises to the level of significant unfairness or unconscionability.

See generally Miglin v. Miglin, 2003 SCC 24, paras. 79–91 and Anderson v. Anderson, 2023 SCC 13, para. 51.

Answer 2

australia

Financial agreements, whether entered into before, during, or after the relationship, are legally binding if they meet the criteria set out in Part VIIIA of the Family Law Act. The rules are technical and it may be that an agreement is unenforceable because they weren’t followed, but the financial terms themselves are not generally limited.

They do not have to be “fair”.

s 90K sets out when a financial agreement is unenforceable. I’m not going to list all of them here but suffice to say, mere unfairness is not one of them.

Answer 3

california

In the US State of California, prenups are contracts. The contract is enforced in a contested divorce (i.e.: when parties disagree) through the family courts, and this specific type of contract is governed by the Uniform Premarital Agreement Act. The CA FAM § 1615 in it specifies two ways in which the contract may be ruled unenforceable:

(1) That party did not execute the agreement voluntarily.

(2) The agreement was unconscionable when it was executed and, before execution of the agreement, all of the following applied to that party:

(A) That party was not provided a fair, reasonable, and full disclosure of the property or financial obligations of the other party.

(B) That party did not voluntarily and expressly waive, in writing, any right to disclosure of the property or financial obligations of the other party beyond the disclosure provided.

(C) That party did not have, or reasonably could not have had, an adequate knowledge of the property or financial obligations of the other party.

The word "fair" only shows up in 2(C), where "fair ... disclosure" of assets and liabilities is required as a precondition for the contract signing.

So if all the statutory conditions were met, then the agreement is enforceable.

Some parts of the agreement may be unenforceable because the statute precludes them or because the enforcement would be unconscionable. FAM § 1612 governs that. Again, not a question of "fairness".

Worth noting that "unconscionable" doesn't mean "unfair". For example, not allowing one spouse to become destitute may be unfair towards the other spouse, but the alternative would be unconscionable.