Signed by both, in a record.
A postnuptial agreement is enforceable without consideration and takes effect when both spouses sign. Nothing oral, nothing by one spouse’s deed, nothing by living as if it existed.

Colorado lets married couples sign a marital agreement under the same 2014 act that governs prenups: to define a company and its growth, settle an inheritance, restructure after a hard season, or make the estate plan and the marriage tell the same story. The rules are strict and specific. Both signatures in a record; a real chance at independent counsel; a conspicuous notice of the rights being waived; a good-faith disclosure of property, debts and income. Miss one and the agreement can be set aside years later without any other showing. Maintenance and fee terms are re-tested for unconscionability when they are enforced. This page is the act, the cases that shaped it, and the process that survives both.
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A postnup is not a lighter document than a prenup. It is the same document, signed by two people who already know exactly what they are giving up.
That is what makes a marital agreement both easier and harder than a prenup. Easier, because the couple is not planning a wedding under a deadline and the estate is a known quantity: the company exists, the inheritance has arrived, the accounts have statements. Harder, because a court asked to enforce it years later will ask why two married people rewrote their financial relationship mid-stream, and the answer has to be visible in the document and the file. A postnup with a reason behind it, a real disclosure attached, and a lawyer on each side reads as a bargain between partners. One signed in a week, under pressure, with no schedule and no counsel reads as something else, and the statute gives the spouse who signed it four separate ways out.
Colorado’s Marital Agreements Act, in force for agreements signed on or after July 1, 2014, is a checklist. Every element on it is something the drafting lawyer controls: the time between draft and signing, the offer to pay for the other side’s counsel, the notice in the text, the schedule of assets with a good-faith value on each line. What follows is the checklist, the limits the act puts on what an agreement can do, the two 2021 Supreme Court decisions that ended the oral-agreement and one-signature deed arguments, and the way the death-rights statute now points back at this act. The last section is how postnups are attacked, because a document is drafted best by the lawyer who knows how it will be challenged.

Signed by both, in a record.
A postnuptial agreement is enforceable without consideration and takes effect when both spouses sign. Nothing oral, nothing by one spouse’s deed, nothing by living as if it existed.
Four ways to set one aside.
Involuntary consent or duress; no access to independent counsel; no notice of the rights being waived, for an unrepresented spouse; and inadequate financial disclosure. The Marital Agreements Act governs agreements signed on or after July 1, 2014.
Maintenance terms are tested later.
A maintenance or attorney-fee provision is unenforceable insofar as it is unconscionable when it is enforced, decided by the court as a matter of law, not when it was signed.
The act defines the document by the couple’s intent. Spouses who intend to stay married sign one thing; spouses on the way to court sign another.
| Prenuptial agreement | Postnuptial (marital) agreement | Separation agreement | |
|---|---|---|---|
| Who signs | Two people who intend to marry | Two spouses who intend to remain married | Two spouses who intend to divorce or legally separate, with a case anticipated or pending |
| The statute | Marital Agreements Act, C.R.S. § 14-2-301 et seq. | The same act | The dissolution statute, C.R.S. § 14-10-112 |
| When it takes effect | On marriage | On signing by both parties | When the court approves it and enters the decree |
| Consideration | None required | None required | Not the question; the court reviews it |
| Court review | Only if challenged: the four statutory grounds, plus unconscionability of maintenance and fee terms at enforcement | The same | Always: property and maintenance terms for unconscionability; children’s terms for best interests |
| What it can cover | Maintenance; rights to property, including characterization, management and ownership; responsibility for liabilities; rights at separation, divorce or death; attorney fees | The same | Everything in the case, subject to the review |
| What the court does with the label | Nothing: substance governs | Nothing: an agreement signed while a divorce is being pursued is a separation agreement whatever it is called | The same |
The act does not apply to an agreement that requires court approval to become effective or to an agreement between spouses who intend to obtain a dissolution or legal separation, signed when a proceeding is anticipated or pending. The Court of Appeals set aside a mid-marriage agreement signed while one spouse was pursuing a foreign divorce, holding it was a separation agreement subject to the dissolution statute’s unconscionability review. Reconciling couples should say in the agreement that they intend to remain married, and the file should show it.
The reasons cluster. Each of them changes what the agreement has to say.
Operating agreements increasingly require a spousal consent or waiver before a member may hold an interest. A marital agreement defines the company and its growth as separate, sets a valuation formula for the other spouse’s share, and keeps the buy-sell and the divorce from contradicting each other.
Money that arrives during the marriage is separate property by statute, but its growth is marital and its commingling is fatal. The agreement fixes the characterization, and the estate plan on the other side of the family often requires it.
In a second marriage with children on each side, the marital agreement and the wills have to tell the same story, and since 2014 a waiver of the elective share is only good if the marital agreement itself is enforceable.
A couple choosing to stay together after an infidelity or a financial breach sometimes wants the money taken off the table so the marriage can be about the marriage. It is a legitimate reason, and it must be drafted without the penalty clauses the act forbids.
The spouse who steps back to raise children is giving up earnings and retirement accrual. A marital agreement can set the maintenance and property terms that make that decision safe, in advance, rather than leaving them to a formula years later.
An agreement signed the week of the wedding, without disclosure or counsel, is a challenge waiting for a date. A marital agreement can affirm, modify or replace it, this time under the checklist.
The act puts the burden on the party attacking the agreement, and gives that party four independent grounds. Any one is enough.
| The ground | The statute | What it means in practice |
|---|---|---|
| Involuntary consent or duress | The party’s consent to the agreement was involuntary or the result of duress. | Ultimatums, a closing or funding deadline, a pregnancy, a business partner’s demand, a threat to leave. The calendar is the evidence: weeks between draft and signature, and no deadline tied to the signature. |
| No access to independent counsel | The party did not have access to independent legal representation: a reasonable time to decide whether to retain a lawyer and to locate one, obtain the advice and consider it; and, if the other party is represented, the financial ability to retain a lawyer or the other party’s agreement to pay the reasonable fees of one. | The moneyed spouse offers, in writing, to pay for the other spouse’s lawyer, and the file shows the time given. A spouse who declines counsel after a real offer has had access; a spouse who was never given the chance has not. |
| No notice of waiver | Unless the party had independent counsel when the agreement was signed, the agreement did not include a notice of waiver of rights or a plain-language explanation of the marital rights or obligations being modified or waived. | For an unrepresented spouse the statutory notice, conspicuously displayed, is mandatory. It is set out below; a drafter who omits it has handed the other side the case. |
| Inadequate financial disclosure | Before signing, the party did not receive a reasonably accurate description and good-faith estimate of value of the property, liabilities and income of the other party, or did not otherwise have adequate knowledge or a reasonable basis for it. | A schedule, attached, with a good-faith value on each line and the basis for it. Colorado omitted the uniform act’s option to waive disclosure, so a waiver clause does not substitute for the schedule. |
Two more rules sit beside the four. An agreement or amendment not in a record and signed by both parties is unenforceable. And maintenance and attorney-fee terms, in an otherwise valid agreement, are unenforceable insofar as they are unconscionable at the time of enforcement, decided by the court as a matter of law. Property terms are not re-tested this way.
The act is a checklist, and every item on it is something the drafting lawyer controls.
The three elements a drafter builds into the document itself.

An unrepresented spouse must get the statutory notice of waiver, conspicuously displayed; both spouses must have had a real chance at independent counsel; and each must receive a good-faith schedule of the other’s property, debts and income before signing.
For a party without independent counsel the agreement must contain a notice, conspicuously displayed, substantially similar to the statute’s text: If you sign this agreement, you may be: giving up your right to be supported by the person you are marrying or to whom you are married; giving up your right to ownership or control of money and property; agreeing to pay bills and debts of the person you are marrying or to whom you are married; giving up your right to money and property if your marriage ends or the person to whom you are married dies; giving up your right to have your legal fees paid. The alternative is an explanation in plain language of every right being modified or waived. I include both, in every agreement, whether or not both spouses are represented; it costs a page and forecloses a ground.
The statute does not require that both spouses have lawyers. It requires that both had access: a reasonable time to decide, to find a lawyer, and to consider the advice; and money to pay for one, or the other spouse’s written agreement to pay. In practice the moneyed spouse’s lawyer drafts, sends the draft with a letter recommending independent counsel and offering to pay for it, and waits. A spouse who declines after that has had access. The drafting lawyer never advises both spouses, and never lets the file suggest otherwise.
A reasonably accurate description and good-faith estimate of value of the property, liabilities and income of each spouse, before signing. It is a schedule, attached as an exhibit, listing each asset and debt with a value and the basis for it, and each spouse’s income with the return that supports it. For a business it names the entity and states a value with the method; a formal appraisal is not required but a stale number or an omitted interest is the most common ground on which postnups fall. Disclosure is as of now, not as of the wedding, which is the point of signing during the marriage.
The act lists the terms a court will not enforce, and the cases add the maintenance rule.
| The term | The rule | The practical consequence |
|---|---|---|
| Child support | Unenforceable to the extent it adversely affects a child’s right to support. | Support is the child’s right, set by the guideline; the agreement cannot cap or waive it. |
| Parenting | A term defining the rights or duties of the parties regarding custodial responsibility is not binding on the court. | The court decides parenting time and decision-making on the child’s best interests when the time comes. A parenting plan in a postnup is a statement of intent, nothing more. |
| Domestic violence remedies | Unenforceable to the extent it limits or restricts a remedy available to a victim of domestic violence. | No waiver of protection-order rights. |
| The grounds for divorce | Unenforceable to the extent it purports to modify the grounds for a court-decreed legal separation or dissolution. | Colorado is a no-fault state; the agreement cannot make it otherwise. |
| Penalties for filing | Unenforceable to the extent it penalizes a party for initiating a legal proceeding leading to a legal separation or dissolution. | A clause that costs a spouse money for filing first is void. Infidelity clauses are drafted against this limit and the public-policy limit, and no Colorado appellate decision has enforced one. |
| Public policy | Unenforceable to the extent it violates public policy. | The catch-all the courts use for terms that shock them. |
| Maintenance and attorney fees | Enforceable, but unenforceable insofar as the provisions are unconscionable at the time of enforcement, decided by the court as a matter of law. | The Supreme Court applied the rule to a fee waiver signed by a spouse later disabled and raising triplets while the other spouse held roughly ten million dollars; the Court of Appeals has applied it to maintenance waivers at dissolution. A bare waiver is the term most likely to be re-tested; a formula with a floor survives better. |
The maintenance rule is the one clients most often misunderstand. Property terms are locked when the four elements are met. Maintenance and fee terms are locked only until the day they are enforced, and then tested against the circumstances that exist that day. A spouse who leaves the workforce, becomes ill or is raising children the agreement did not anticipate can ask the court to declare a waiver unconscionable, and sometimes wins.
Two Colorado Supreme Court decisions in 2021 settled the arguments couples had been making for decades.

An oral agreement to keep property separate is not valid however long the couple lived by it, and a deed from one spouse is not a marital agreement. The act requires a record signed by both, for the agreement and for every amendment.
A marital agreement must be in a record and signed by both parties; it is enforceable without consideration; it is effective on signing by both parties; and an agreement or amendment not in a record and signed by both is unenforceable. Four sentences, and each of them has ended a case.
In Zander the spouses had agreed, in 2007 and out loud, to keep their inheritances and retirement accounts separate, and had lived that way for years. The Supreme Court held the agreement was neither in writing nor signed by both parties and was not valid, and that there is no partial-performance exception to the statute. Years of behaving as if the deal existed did not create it.
In Blaine, decided the same day, a husband had signed an interspousal deed conveying the home to his wife. The Court held that the marital-property presumption yields only through the four statutory exceptions, that the relevant exception requires a valid agreement, and that a valid agreement must be in a record and signed by both parties. A deed from one spouse is not a marital agreement, however clear the intent.
Every understanding the couple has about their property goes into the record and gets two signatures, including the ones they have lived by for years. Every amendment gets the same. The agreement is notarized so that title companies and the probate court accept it. And the retitling of accounts and real estate that the agreement calls for is done after it is signed, not in place of signing it.
Since 2014 the probate code points back at this act. A postnup that fails the checklist fails at death as well as at divorce.

A waiver of the elective share and other death rights made since July 1, 2014 is enforceable only inside a marital agreement that satisfies this act, and the agreement waives rights without transferring anything: the will, the trust and every beneficiary form still have to be changed to match.
A surviving spouse in Colorado has an elective share of the augmented estate, a homestead allowance, exempt property and a family allowance, and the right to take under an intestate estate. The probate code allows all of them to be waived, but for a waiver made on or after July 1, 2014 only if the waiver is contained in a premarital or marital agreement, as defined in the Marital Agreements Act, that is enforceable under that act. The four grounds, the notice, the counsel rule and the disclosure therefore govern the death-rights waiver exactly as they govern the divorce terms, and a spouse’s estate can attack the agreement on the same footing a divorcing spouse could.
A marital agreement waives rights; it does not move property. The will, the revocable trust, the retirement plan beneficiary designations, the transfer-on-death deeds and the life insurance all have to be changed to match it, or the plan pays the spouse the agreement said would take nothing, and federal law will honor the designation over the agreement for an ERISA plan. I draft the agreement and the estate-plan amendments together, or with the estate lawyer in the room, so the two documents tell one story.
Transfers between spouses during the marriage are not taxable events under federal law, so retitling accounts and real estate to match the agreement generally carries no income tax; the basis carries over. Confirm the specifics with the CPA before anything moves, particularly for a business interest or a property with depreciation history.
Eight steps, in order, each of them aimed at one of the grounds above.
The recital states the reason: the company, the inheritance, the estate plan, the reconciliation. An agreement with a visible reason reads as a bargain between partners; one without reads as pressure.
The drafting lawyer represents one spouse and says so in writing. The other spouse is sent the draft with a recommendation to retain independent counsel and a written offer to pay the reasonable fees. Then the file waits.
Time between the first draft and the signature is the best evidence of voluntariness. No closing, funding or ultimatum deadline is tied to the signature, and nothing is signed in the same month as a threat to leave.
Each spouse’s property, debts and income, with a good-faith value and its basis on every line, attached as exhibits and initialed. The business gets a stated value and method; the returns are exchanged. Disclosure is as of now.
Both, conspicuously, whether or not both spouses have counsel. A page that forecloses a ground.
A formula with a floor, or a term that steps down with the length of the marriage, survives the unconscionability-at-enforcement test far better than a bare waiver.
The agreement and every future amendment. Nothing oral, nothing by one signature, nothing by conduct.
Accounts, deeds and beneficiary designations are changed to match the agreement within the month, and the wills and trusts are amended. Then the agreement is re-read at every major life change and amended, in a signed record, when the facts move.
Every ground above, from the other side of the table. A drafter who knows the attacks writes against them.
| The attack | What the challenger has to show | What defeats it |
|---|---|---|
| Duress | An ultimatum; a deadline tied to a closing, a funding or a business deal; pregnancy; immigration or financial dependence; a threat to leave. | A calendar showing weeks between draft and signature, no deadline, a recital of the reason, and the challenger’s own lawyer’s letters. |
| No access to counsel | No time, no money and no offer to pay; a draft delivered the day of signing. | The written recommendation to retain counsel, the written offer to pay, and the dated correspondence showing the time given. |
| No notice | An unrepresented spouse, and an agreement without the conspicuous notice or a plain-language explanation. | The notice, on its own page, initialed. |
| Inadequate disclosure | A missing schedule; an omitted business interest, trust, option grant or account; a stale or bad-faith value; income understated. | The exhibits, with values and their basis, the returns exchanged, and the challenger’s initials on each page. |
| Unconscionable now | That the maintenance or fee term, applied today, leaves a spouse in circumstances a court will not accept: disability, children, a wide gap in means. | A formula rather than a waiver; a floor; a term that anticipated the bad case. Property terms are not subject to this attack. |
| A forbidden term | A penalty for filing, a term touching child support or parenting, a domestic-violence waiver, a public-policy violation. | The term is severed and the rest survives, if the agreement was drafted with a severability clause and the forbidden term was never load-bearing. |
| “You were already headed to divorce” | That the agreement was signed while a dissolution was anticipated or pending, making it a separation agreement subject to the court’s unconscionability review. | A recital that the spouses intend to remain married, and a file that shows it: no consultation with a divorce lawyer, no petition drafted, no separation. |
When I am on the attacking side, the disclosure schedule is where I start; when I am drafting, it is where I spend the most time. The Hidden Assets page covers what an omitted interest looks like and how it is found.
Six things, before either of you signs. Not legal advice for your case; the mistakes I have watched for thirty years.

Voluntariness, access to counsel, the notice, the disclosure. A postnup is not a lighter document; it is the same document with a known estate.
A company, an inheritance, a reconciliation, an estate plan. An agreement with a reason behind it reads as fair; one without reads as pressure.
The schedule attached to a postnup is the estate as it exists now. An omitted business interest is the most common way one fails.
It is the cheapest insurance the agreement can have, and the offer to pay is itself evidence.
A bare waiver is the term most likely to be set aside as unconscionable at enforcement. A formula with a floor survives.
The agreement waives rights and transfers nothing. The estate plan has to match it or the plan pays the wrong person.
A postnup is easier to get than a prenup.
It is the same act with the same four grounds, and a court will ask why two married people rewrote their finances mid-stream. The reason has to be in the document.
We've lived by our agreement for years, so it counts.
The Supreme Court held in 2021 that an oral agreement to keep property separate is not valid and that there is no partial-performance exception.
My spouse signed the deed, so the house is mine.
A deed from one spouse is not a marital agreement. The marital presumption yields only to a record signed by both.
A maintenance waiver is forever.
It is enforceable unless it is unconscionable on the day it is enforced. Disability, children and a wide gap in means reopen it.
We can waive disclosure.
Colorado left the uniform act’s waiver option out. A missing schedule is a ground to set the agreement aside, waiver clause or not.
The postnup takes care of what happens if I die.
Only if it is enforceable under the act, and only as a waiver. The will, the trust and the beneficiary designations still have to be changed.
A marital agreement is drafted best by the lawyer who knows exactly how it will be attacked.
Start with a confidential conversation: tell me about the agreement →
It matters a great deal. The Marital Agreements Act covers agreements between spouses who intend to remain married. It does not apply to an agreement between spouses who intend to divorce, signed when a case is anticipated or pending; that is a separation agreement, which the court reviews for unconscionability under the dissolution statute and can reject. The Court of Appeals has set aside a mid-marriage deal signed while a divorce was being pursued on exactly that basis, whatever the document called itself. A couple who are reconciling should say so in the agreement, and mean it; a couple who are negotiating an exit should sign a separation agreement and get it approved.
You can, if the refusal is real and the document is built for it. A party who lacked access to independent counsel can void the agreement, so the unrepresented spouse must have had a reasonable time to decide whether to hire a lawyer, find one and consider the advice, and, if the other spouse is represented, either the money to hire one or the other spouse’s offer to pay. Then the agreement itself must carry the statutory notice of waiver of rights, conspicuously displayed, or a plain-language explanation of every right being modified or waived. Omit that and an unrepresented spouse can set the agreement aside years later without proving anything else.
You have to give a reasonably accurate description and a good-faith estimate of the value of your property, liabilities and income, or your spouse has to have adequate knowledge of them already. Colorado deliberately left out the uniform act’s provision letting a party waive disclosure, so a waiver clause does not cure a missing schedule. For a business owner that means a schedule that names the company, states a good-faith value with its basis, and attaches or references the financial statements; a stale or omitted business interest is the most common way a postnup fails.
No. The Colorado Supreme Court held in 2021 that an oral agreement to keep inheritances and retirement accounts separate was neither in writing nor signed by both parties and was not valid, and that there is no partial-performance exception. A deed signed by one spouse alone does not do it either: the marital presumption yields only through the statutory exceptions, and a valid agreement must be in a record signed by both spouses. If you want the arrangement you have been living to be the one the court enforces, sign it.
It can waive or fix maintenance, and the waiver will usually hold, but not unconditionally. The statute makes maintenance and attorney-fee terms unenforceable insofar as they are unconscionable at the time of enforcement, decided by the court as a matter of law. The Supreme Court applied that rule to a fee waiver signed by a spouse who was later disabled and raising triplets while the other spouse held about ten million dollars. Property terms are not re-tested this way; maintenance and fees are. Draft the maintenance term with the bad case in mind, or with a formula rather than a bare waiver.
A term that penalizes a party for initiating a divorce or legal separation is unenforceable, and so is one that purports to change the grounds for divorce or violates public policy; an infidelity clause has to be drafted with those limits in front of it, and no Colorado appellate court has enforced one. Custody and parenting terms are not binding on the court, which decides the children’s issues on their best interests. A term that adversely affects a child’s right to support is void.
Both. Since July 1, 2014 a waiver of the elective share and other death rights is enforceable only if it is contained in a premarital or marital agreement that is itself enforceable under the Marital Agreements Act, so the postnup has to satisfy every element above to work at death. And the agreement waives rights; it transfers nothing. The will, the trust and every beneficiary designation still have to be changed to match it, or the retirement plan pays the spouse the agreement said would take nothing.
The statute does. You are entitled to a reasonable time to decide whether to retain counsel, to find one and to consider the advice, and if your spouse is represented, either the means to hire your own lawyer or your spouse’s agreement to pay the reasonable fees of one. You are entitled to a good-faith disclosure of the company’s value and your spouse’s income, which is the number the waiver is worth. And a signature obtained under an ultimatum with a closing deadline is the first thing a court looks at on a claim of duress. Take the time, take the lawyer, and have the fee paid by the side that wants the signature.
The next page in this chapter, the pages that belong with it, and the blog posts on the same question.
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