Postnuptial Agreement
A postnuptial agreement does what a prenup does, signed after the marriage has begun. Couples reach for one when circumstances change — a business is started, an inheritance arrives, one spouse leaves work to raise children, or the marriage is being repaired and both want clarity.
Signed between spouses, and scrutinised more closely
A prenuptial agreement is negotiated between two people who are not yet legally bound to each other. A postnuptial agreement is negotiated between spouses, who in most states owe each other a fiduciary duty. That changes the standard: courts examine postnups more carefully, and disclosure that would have been adequate before the wedding may not be adequate after it. The care that goes into the process matters even more here.
What the template covers
Why the agreement is being made
Stating the circumstances — a new business, an inheritance, a career change — helps establish that both parties acted deliberately rather than under pressure.
Complete and current disclosure
Not the position at the wedding, but the position now, including anything acquired since. Both sets of schedules attached to the agreement itself.
Property acquired during the marriage
The central question of most postnups: how what has already been built together, and what will be built from here, is treated.
Independent legal advice for each spouse
More important here than in a prenup, precisely because of the fiduciary relationship between the parties.
Recognition varies by state
The Uniform Premarital Agreement Act addresses agreements made before marriage; postnuptial agreements are largely governed by state case law and, in some states, by specific statute. Most states enforce them, applying heightened scrutiny because of the fiduciary duty spouses owe one another — a duty that in community property states such as California is expressly codified. A minority of states are markedly more restrictive, particularly where the agreement was negotiated while a separation was already contemplated. As with prenuptial agreements, child support and custody cannot be bindingly fixed in advance, and the ESIGN Act excludes family law matters at 15 U.S.C. § 7003, so state execution requirements govern the signature.
A business that grew after the wedding
One spouse launched a company three years into the marriage, funded partly from savings that predated it. By year seven it was the family's main asset and the couple had no agreement about how it would be treated. Neither wanted to litigate the question later, and neither could answer it confidently. A postnuptial agreement with proper disclosure settled it in a few weeks, at a cost that was a rounding error against what a contested valuation would have run. What made it work was that the marriage was not in trouble. Both had counsel, both disclosed fully, and neither was deciding under pressure — which is precisely the combination that makes an agreement hold. Couples who wait until the relationship is strained find that the same document is harder to negotiate and easier to challenge later, for reasons that have nothing to do with its terms.
Questions people ask about this
Are postnuptial agreements enforceable?
In most states, yes, subject to closer scrutiny than a prenup because of the fiduciary duty between spouses. A minority of states are considerably more restrictive, so the governing state matters.
How is a postnup different from a separation agreement?
A postnuptial agreement is made by spouses who intend to stay married. A separation agreement is made when they are separating and typically resolves immediate matters such as living arrangements and interim support.
Do we both need lawyers?
Strongly advisable. Independent counsel for each spouse is the most effective protection against a later challenge, and its absence is one of the first things a court examines.
Can a postnup be changed later?
Yes, by a further written agreement signed by both spouses with the same care as the original — including current disclosure.