When a business has been built up over generations, or is shared with parents and siblings, a divorce can put far more than one couple at risk. Because a court can bring the value of a business interest into a settlement, one person's divorce can ripple out to co-owners, employees and the wider family who depend on the firm. A prenup – ideally paired with the business's own shareholder or partnership agreement – is a key tool for protecting a family business and keeping it in the family. This guide explains the risk, how a prenup helps, and how to balance protection with the fairness a court requires.
Why a family business needs protecting
On divorce, a court can take the value of a business interest into account as part of the overall financial picture. To meet a settlement, that can mean:
- finding cash to pay the other partner their share of the value;
- selling assets, or even part of the business, to raise that cash;
- bringing an ex-spouse into the ownership picture, which co-owners rarely want;
- in the worst case, disrupting the business itself at a difficult time.
Where other family members are shareholders or partners, the fallout spreads well beyond the divorcing couple – which is why families with a shared enterprise so often plan ahead. See how a business is treated in a divorce for the underlying rules.
How a prenup helps
A prenup can record that your share in the family business – and often its future growth – is your separate property, kept out of the matrimonial pot. Include the business in your disclosure with a sensible valuation (see how to value your assets), and set out how any increase in value during the marriage should be treated. For an individually owned business, the wider picture is in prenups for business owners.
Pair it with a shareholder or partnership agreement
The strongest protection combines two documents. The prenup deals with the position between the spouses. The shareholder or partnership agreement governs the business itself and can restrict who is allowed to hold a stake – for instance, requiring shares to stay within the family and giving other owners pre-emption rights. Together they make it far harder for a divorce to force an outsider into the ownership, and are often reinforced by a family trust.
Valuation and growth during the marriage
Valuing a family business is rarely simple – goodwill, retained profits and illiquid assets all complicate it. A prenup should record a sensible valuation basis and distinguish the value you brought into the marriage from growth achieved during it. Where the non-business spouse contributed to that growth (directly or by supporting the family), a fair approach to sharing it is what keeps the agreement robust.
Balance protection with fairness
A court will still ensure both partners' needs are met (see are prenups legally binding?), so the strongest agreements protect the business itself while making fair provision for the non-business spouse from other resources – the house, savings or maintenance. Given the stakes, this is an area where independent legal advice is well worth it.
Protecting a family business: prenup plus shareholder agreement
The strongest protection for a family business pairs a prenup with the business's own shareholder or partnership agreement. The prenup ring-fences your share and its future growth as separate property; the shareholder agreement restricts who can hold a stake. Disclose the business with a sensible valuation, and make fair provision for the non-business spouse from other assets so the agreement is both protective and fair.
Why the prenup carries weight: Radmacher
The reason a family-business clause is worth having comes back to Radmacher v Granatino (2010), where the Supreme Court held that a court should give effect to a freely made, fair agreement unless it would be unfair to hold the parties to it. A prenup is not automatically binding – the court retains its discretion under the Matrimonial Causes Act 1973 and will always meet a partner’s and any children’s needs – but a fair agreement made with full disclosure, independent legal advice on both sides, and signed at least 28 days before the wedding (as the Law Commission suggested) is now given real weight. For a business shared with parents and siblings, that weight can be the difference between keeping the firm intact and having to raise cash to buy out a departing spouse.
A worked example: keeping the firm in the family
Imagine a third-generation family manufacturing company, owned in equal shares by three siblings. One sibling marries. Without planning, a later divorce could see the value of that sibling’s stake brought into the settlement, forcing the family to find cash – or, worse, to sell part of the business – to pay it. With a prenup recording the share as separate property, backed by a shareholder agreement that keeps shares within the family and gives the other siblings pre-emption rights, the outcome is very different: the spouse is provided for fairly from other resources such as savings, the family home or maintenance, and the company’s ownership is left undisturbed. That is the combination families rely on.
Common mistakes with a family-business clause
- Relying on the shareholder agreement alone. It governs the company, not the marriage; only a prenup addresses the position between spouses.
- Using a vague or optimistic valuation. Goodwill and retained profits complicate matters, so record a sensible, professionally informed basis (see how to value your assets).
- Ignoring a spouse’s contribution. If they work in the business or support the family, a fair share of growth keeps the clause robust.
- Never updating it. As the business grows, a review clause keeps the agreement current.
What if your spouse works in the business?
Family firms often draw in a spouse – running the books, managing staff, building the client base – and that changes the fairness analysis. If your husband or wife has contributed directly to the business during the marriage, a court is far less likely to treat the whole of its growth as your separate property, because they helped create that value. A realistic prenup recognises this: it can protect the value you brought in and the family’s underlying stake, while sharing a fair portion of the growth their work helped generate. It can also address practical points such as whether a spouse who leaves the business is compensated for their contribution. Ignoring a working spouse’s input, and trying to keep everything, is exactly the kind of overreach that makes an agreement vulnerable (see when is a prenup unfair?). Where a couple genuinely run the firm together, see prenups when a couple runs a business together.
Succession planning and the next generation
A prenup is one piece of a wider succession picture. Families who want a business to pass down the generations typically combine several tools: a prenup for each family member who marries, a shareholder or partnership agreement keeping shares within the family, sometimes a family trust holding the shares outside any one person’s estate, and up-to-date wills. Encouraging every family member who marries to put a prenup in place – not just one – closes the gaps, because the business is only as protected as its most exposed owner. For the wider individual picture, see prenups for business owners.
Family business prenup FAQs
Does the prenup carry weight after Radmacher?
Yes – since Radmacher v Granatino (2010) a fair, well-informed agreement is given significant weight, though needs come first (see are prenups legally binding?).
Should other family members take advice too?
It is wise – the shareholder or partnership agreement affects them all, and coordinating it with each owner’s prenup gives the firm the strongest protection.
Can a divorce force the sale of a family business?
Courts try to avoid it, often offsetting against other assets (see how a business is treated in a divorce).
What about a business I run on my own?
See prenups for business owners for the wider picture.
Does a shareholder agreement do the same job as a prenup?
No – they cover different ground and work best together, one governing the marriage and one governing the company.
How is a family business valued for a prenup?
With a sensible, professionally informed valuation recorded in your disclosure (see how to value your assets).
What if my spouse works in the family business?
Their contribution is relevant, so a fair approach to sharing growth keeps the agreement durable (see prenups when a couple runs a business together).
Create your prenuptial agreement online
UK Prenup lets couples in England & Wales create a clear, fair prenuptial agreement online from £199, with your document generated instantly as a PDF. See how it works or get started.
UK Prenup is not a law firm and does not provide legal advice. A prenuptial agreement in England & Wales is not automatically binding, and both partners should take independent legal advice before signing.