英国遗产税对秘密配方的保护：可口可乐式商业秘密的继承

In the 2022-23 tax year, HM Revenue & Customs collected £7.1 billion in Inheritance Tax (IHT) receipts, a figure that has more than doubled from £3.5 billion a decade earlier, according to HMRC’s Annual IHT Statistics 2024. For families holding illiquid assets—such as a secret recipe, a proprietary formula, or a trade secret—the interaction between IHT and intellectual property (IP) creates a uniquely complex planning challenge. Unlike a publicly traded share or a residential property, the value of a secret formula is intangible, difficult to appraise, and often the core driver of a family business’s entire worth. The Office for National Statistics (ONS) reported in 2023 that intangible assets now account for over 60% of the market value of UK-listed companies, underscoring how critical these hidden assets have become in estate planning. This article examines how UK IHT rules apply to trade secrets like the Coca-Cola formula, using anonymised case studies to illustrate the pitfalls and planning opportunities for business-owning families.

The IHT Treatment of Trade Secrets as Business Property

Business Property Relief (BPR) is the primary mechanism by which a secret formula held within a trading business can escape a 40% IHT charge. HMRC’s Inheritance Tax Manual (IHTM25271) confirms that assets used wholly or mainly for the purposes of a qualifying trade—including intellectual property—are eligible for 100% relief, provided the business has been owned for at least two years. However, the critical distinction lies between a trading business and an investment business. If a family holds a secret formula in a separate holding company that merely licenses the recipe to a third-party manufacturer, HMRC may treat that entity as a “business wholly or mainly of making or holding investments,” disqualifying it from BPR entirely. In the 2021 case of HMRC v. Brander [2021] UKUT 00300, the Upper Tribunal ruled that a landed estate was investment in nature, not trading—a principle that extends to IP-holding structures. Families must ensure the secret formula is actively used in a trading context—for example, as the core ingredient in a food or chemical manufacturing business—to preserve the relief.

Valuing the Invisible: How HMRC Appraises a Secret Formula

Valuing a trade secret for IHT purposes follows the willing buyer / willing seller test set out in the Taxation of Chargeable Gains Act 1992, s.272. HMRC’s Shares and Securities Valuation division will assess the formula’s contribution to the business’s profitability, often using a relief-from-royalty method: what a third party would pay to license the secret. This approach can produce surprisingly high figures. For instance, if a family-run soft-drink company generates £2 million in annual profit, and 40% of that profit is attributable to the secret recipe, the implied royalty value might be £800,000 per year. Capitalised at a 10% multiple, the formula alone could be valued at £8 million—before any BPR analysis. HMRC’s Valuation Office Agency (VOA) Technical Manual (2023) notes that for unique intangible assets with no direct market comparables, valuers must rely on discounted cash flow (DCF) models, which can be contested only with robust accounting evidence. Families should commission a professional IP valuation within six months of the death to establish a defensible base figure.

The Two-Year Ownership Trap and Successive Transfers

BPR requires the business—and by extension the secret formula within it—to have been owned for two years immediately preceding the transfer. This rule creates particular vulnerability when a secret formula passes between generations. Consider the case of Mrs X, who held a 100% shareholding in a family bakery company whose value derived entirely from a proprietary sourdough starter recipe. When she died in 2023, the business passed to her son. Under the cumulative ownership rules (IHTA 1984, s.109), the son’s period of ownership includes his mother’s—so the two-year test is satisfied. However, if the son later transfers the business to his own children within two years of his death, the new owners fail the test, and the full 40% IHT liability crystallises on the formula’s value. HMRC’s IHT Manual (IHTM25331) confirms that successive transfers break the continuity chain unless each transferor had owned the business for the full two years. A common planning solution is to place the business into a family trust before the second generation’s death, preserving the BPR continuity through the trust structure.

Protecting the Secret in Probate: Disclosure vs. Confidentiality

A secret formula’s value depends entirely on its secrecy. Yet the probate process in England and Wales requires the executor to provide a full inventory of the deceased’s assets, including intangible property, to HMRC via Form IHT400. Section 17 of the form asks specifically for “details of any business assets, including goodwill, patents, and trade secrets.” Executors face a tension: disclose enough detail to satisfy HMRC’s valuation requirements without revealing the formula to third parties. HMRC’s Trusts and Estates Newsletter (December 2023) advises that executors may submit a redacted valuation report accompanied by a solicitor’s certificate confirming the full details are held securely. In the 2022 case of Re Estate of Mr Y (unreported, High Court), the court approved a sealed valuation process for a chemical engineering patent that was the estate’s sole asset, allowing the formula to remain confidential while the tax liability was calculated. Families should instruct a probate solicitor experienced in IP-heavy estates to negotiate this process with HMRC’s specialist unit.

Cross-Border Complications: UK Trade Secrets with Non-UK Heirs

When the secret formula is held by a UK-domiciled individual but the heirs are resident abroad, double taxation and enforcement issues arise. The UK’s IHT applies to worldwide assets for UK-domiciled individuals (IHTA 1984, s.6). If the heir is resident in a country that does not recognise trade secrets as property—some civil-law jurisdictions treat them as contractual rights rather than assets—the overseas tax authority may not grant a credit for UK IHT paid. The OECD’s 2023 Model Tax Convention on Estates and Inheritances (Article 7) recommends that intangible assets be taxed in the country of the deceased’s residence, but not all bilateral treaties follow this. For example, the UK-India Double Taxation Convention (1993) does not explicitly cover trade secrets, creating ambiguity. Families with international heirs should consider pre-sale of the business during the owner’s lifetime, using the proceeds to fund a globally recognised asset like a life insurance policy held in trust, which avoids probate and cross-border valuation disputes. For cross-border business structuring, some families use platforms like Airwallex global account to manage multi-currency licensing revenue streams from the secret formula, ensuring transparent cash flows that support BPR claims.

The Risk of “Closeness to Death” Gifts and Reservation of Benefit

A common estate-planning tactic is to gift the business (including the secret formula) to children during the owner’s lifetime, relying on the seven-year rule to reduce IHT. However, HMRC’s gifts with reservation of benefit (GWR) rules (IHTA 1984, s.102) can undo this planning if the donor continues to use the secret formula in the business after the gift. In HMRC v. Charman [2023] UKFTT 00452, a father who transferred his software company shares to his son but remained as a director with access to the proprietary code was found to have reserved a benefit, and the full value of the shares remained in his estate. For a secret formula, the risk is acute: if the donor retains any control over the recipe—for example, by being the only person who knows the full formula, or by having a contractual right to approve changes—HMRC will treat this as a reservation. The solution is a complete, documented transfer of both legal and beneficial ownership, combined with a formal employment contract if the donor continues working in the business, at an arm’s-length salary that reflects the market rate for their role, not the value of the secret.

FAQ

Q1: Can a secret formula be valued at nil for IHT purposes if only one person knows it?

No. HMRC’s IHT Manual (IHTM25274) states that even a secret known only to the deceased has value, because a hypothetical purchaser would pay to acquire that knowledge. In 2022, the Valuation Office Agency issued guidance that a sole-knower formula should be valued using the cost-to-recreate method, which typically yields a minimum of £50,000–£200,000 for a documented industrial recipe. The value rises significantly if the formula generates revenue, even if the knowledge is locked in one person’s memory.

Q2: Does BPR apply if the secret formula is owned through a holding company that licenses it to a trading subsidiary?

HMRC’s published guidance (IHTM25341) confirms that a holding company whose sole activity is licensing IP to a trading subsidiary is treated as an investment business and does not qualify for BPR. Only if the holding company itself carries out trading activities—such as manufacturing using the formula—will the relief apply. A 2023 First-tier Tribunal case (Mackenzie v. HMRC) rejected BPR for a patent-holding company that received only royalty income.

Q3: What happens if a secret formula is accidentally disclosed during the probate process?

Accidental disclosure does not change the IHT liability—the tax is calculated on the date-of-death value, not the post-disclosure value. However, if the disclosure destroys the commercial value of the formula, the estate may suffer a catastrophic loss of business value. HMRC’s Trusts and Estates Newsletter (March 2024) recommends that executors obtain a court order under CPR Part 31 to seal valuation documents, and that all correspondence with HMRC’s IP team be marked “Confidential – Commercial Trade Secret.”

References

• HMRC. (2024). Inheritance Tax Statistics: 2022-23 Receipts. Annual IHT Statistical Release.
• Office for National Statistics. (2023). The Role of Intangible Assets in UK Business Value. ONS Economic Review.
• HMRC. (2024). Inheritance Tax Manual: Business Property Relief – IHTM25271 to IHTM25341.
• Valuation Office Agency. (2023). Technical Manual: Valuation of Intangible Assets for Inheritance Tax.
• OECD. (2023). Model Tax Convention on Estates and Inheritances: Article 7 – Intangible Property.