Prenups and Vesting Equity: What Pre-Liquidity Couples Need to Know in 2026
For couples where one or both partners hold vesting equity at a company expected to go public or run a tender, a prenup is not a hypothetical conversation. It is the document that decides what happens to that equity, and to the appreciation that builds during the marriage, if the relationship ends. Pre-liquidity is the window where the conversation goes from theoretical to specific. This is the 2026 guide for couples planning a wedding with vesting equity in the picture.
Key takeaways
- A prenup decides what happens to vesting equity in a divorce or at death, overriding the state's default rules. For couples with concentrated equity at SpaceX, OpenAI, Anthropic, or similar, the default rules in CA and NY can produce surprising outcomes.
- In community property states (CA, TX, and seven others), equity earned during the marriage is generally community property by default, regardless of whose name is on the cap table. A prenup is how a couple sets explicit rules on what is separate and what is community.
- In equitable distribution states (NY, MA, and most others), vested equity acquired during the marriage is typically marital property subject to fair, not necessarily equal, division. A prenup can carve out specific equity grants as separate.
- Premarital appreciation tracking matters most for pre-IPO equity. If one partner brings 100,000 shares into the marriage at a $20 strike, and those shares are worth $200 each at the IPO five years in, the prenup can address how that appreciation is treated.
- Neptune delivers a flat-fee prenup at $5,000 that covers both partners and both independent state-licensed family law attorneys, with AI-led intake handling the asset and equity disclosure. For couples with cap table structures that require specialized HNW negotiation, Neptune can refer to a traditional matrimonial boutique.
Why the pre-IPO window matters for prenups
State law treats vesting equity in different ways depending on when the grant was made, when it vested, and what happened during the marriage. The cleanest position is to have the prenup signed before the wedding and the equity structure documented in the prenup with specificity.
If a grant was made before the marriage but vests during the marriage, both community property and equitable distribution states have rules for separating the premarital and marital portions. Without a prenup, the courts apply the default formulas, which sometimes split appreciation in ways neither partner would choose if asked.
For pre-IPO couples specifically, the appreciation between vesting and the public event can be material. A prenup that addresses how that appreciation is allocated, particularly across an event like a tender or IPO, removes the ambiguity that drives expensive litigation later.
What a good prenup covers for pre-liquidity couples
A prenup for a couple with vesting equity should address:
- Identification of specific premarital equity with grant dates, vesting schedules, strike prices, and the company name. This is the baseline.
- Treatment of unvested equity that vests during the marriage, including how to characterize the portion attributable to premarital service versus marital service.
- Appreciation during the marriage, with explicit rules on whether premarital separate property appreciation stays separate or becomes community or marital based on factors like commingling or active management.
- Treatment of liquidity events during the marriage, including tender offers, IPOs, and secondary sales. What happens to the proceeds and how they are characterized matters.
- Spousal support provisions where applicable, with the state-specific independent counsel requirements met (California Family Code §1612(c) explicitly requires independent counsel for spousal support provisions).
- Sunset clauses or revisions for couples who want the prenup to adjust over time as the financial picture changes.
Neptune's standard prenup handles the full document set. Each partner gets an independent state-licensed family law attorney from the vetted network. AI handles the financial disclosure and decision mapping, and the attorneys handle drafting and negotiation.
State-specific anchors
For a couple in California, the prenup is drafted under the Uniform Premarital Agreement Act and California Family Code Chapter 1. The 7-day rule under California Family Code §1615(c)(2) requires the final agreement to be presented at least seven calendar days before signing. Community property is the default, so the prenup explicitly designates what is separate.
For a couple in New York, the prenup is drafted under NY Domestic Relations Law §236(B)(3). The agreement must be in writing, subscribed by both parties, and acknowledged in the manner required to record a deed. NY is equitable distribution, not community property.
For a couple in Texas, the prenup is drafted under TUPAA (Texas Family Code Chapter 4). Voluntariness, full disclosure (or knowing waiver), and unconscionability are the enforceability anchors under §4.006. Texas is community property and has a full basis step-up at death.
For a couple in Massachusetts, the prenup is drafted under common law (MA has not adopted UPAA). The two-look standard from DeMatteo v. DeMatteo, 436 Mass. 18 (2002) requires the agreement to be fair both at execution and at enforcement. MA is equitable distribution.
When a postnup is the right answer instead
If the wedding has already happened, the prenup window is closed. A postnup is the during-marriage equivalent. Postnups are generally harder to enforce than prenups because the wedding deadline that pushes prenup conversations forward is gone, and case law in most states treats during-marriage agreements with extra scrutiny. But a properly drafted postnup is still better than ambiguity, especially when a liquidity event during the marriage materially changes the financial picture.
Neptune offers postnups on the same couple-first, flat-fee model as prenups. Each partner gets an independent state-licensed family law attorney from the vetted network.
Related guides
Frequently asked questions
Can Neptune handle a prenup with vesting startup equity?
For couples with standard equity structures (a defined cap table position with normal vesting at a pre-IPO company), Neptune's vetted state-licensed family law attorneys can handle the prenup inside the standard $5,000 flat fee. For couples with multi-entity structures, unusual investor rights, or a near-term liquidity event with complex characterization questions, Neptune is upfront about scope and can refer to a traditional HNW matrimonial firm.
Do we both need to use Neptune?
The standard plan gives each partner their own independent state-licensed family law attorney from the vetted network. If one partner prefers to retain outside counsel from a firm of their choosing, that works as well. Neptune coordinates the disclosure and timing with the outside attorney.
What if the company runs a tender during the marriage and our prenup doesn't address it?
A postnup can be drafted during the marriage to address the new facts. The bar is higher than for a prenup, but a properly drafted postnup is still much better than nothing. Neptune offers postnups on a similar flat-fee model.
Does a prenup affect QSBS treatment of the equity?
A prenup decides what happens to equity in a divorce or at death from a state property law perspective. QSBS is a federal income tax question under Section 1202. The two interact at the edges (for example, a transfer of stock to a spouse can affect the QSBS holding period analysis), but the prenup itself does not change QSBS qualification or the federal exclusion. A specialist should review any prenup provision that transfers QSBS-eligible stock before the event.