Selling an estate or letting agency can generate a significant capital gain. Whether you pay 18% on that gain or closer to 50% depends on decisions made years before a buyer appears. Transaction structure, shareholding arrangements, how deferred consideration is documented, and whether non-compete payments are separately valued — each of these choices has material tax consequences. Understanding them before you reach heads of terms is not optional.
This guide covers the principal tax issues for UK estate and letting agency sellers: CGT basics and current rates, the difference between asset and share sale tax treatment, the qualifying conditions for Business Asset Disposal Relief, earn-out taxation under the Marren v Ingles principle, non-compete payments, vendor loan notes, and when CGT must be paid. It is written for agency owners and their advisers.
Tax rules change. Rates and thresholds referred to here reflect the position as at spring 2026. Always take specialist advice before committing to a structure.
CGT Basics: What You Are Paying Tax On
Capital gains tax arises when you dispose of a capital asset — shares in your company, or the business assets themselves — for more than you paid for them.
Base cost. Your gain is the proceeds minus the base cost (what you originally paid, plus allowable costs such as acquisition legal fees). If you founded the agency, the goodwill you have built has a base cost of nil — you created it from scratch at no capital cost. The entire sale proceeds attributable to goodwill are a chargeable gain.
Annual exempt amount. Each individual has a CGT annual exempt amount — currently £3,000 per tax year. For a transaction generating a gain of several hundred thousand pounds, the exempt amount is a marginal relief.
CGT rates (from 6 April 2026). For higher and additional rate taxpayers, the standard CGT rate on business assets and shares is 24%. Business Asset Disposal Relief (BADR) reduces this to 18% on qualifying disposals, up to a lifetime limit of £1 million.
The difference between 18% and 24% on a £500,000 gain is £30,000. On a £2 million gain it is £120,000. BADR remains significant even with the narrowed gap.
Asset Sale vs Share Sale: The Tax Difference
Every major tax decision in an agency sale follows from one upstream choice: are you selling shares in your company, or is your company selling its underlying assets?
Sole trader or partnership. If you have traded without incorporating, only an asset sale is possible. You own the goodwill, equipment, and other business assets directly. A gain on disposal is subject to CGT in your hands (with BADR available if qualifying conditions are met).
Incorporated agency — share sale. You sell your shares in the company. A qualifying gain is taxed at 18% with BADR, once. On a £1 million gain, tax is £180,000.
Incorporated agency — asset sale (the double-tax problem). If your company sells its assets — goodwill, client data, equipment — the gain is first taxed within the company at corporation tax (25% for profits above £250,000). Then the remaining proceeds must be extracted by the shareholders, either as a dividend (taxed at up to 39.35% for additional rate taxpayers) or via a Members’ Voluntary Liquidation (where distributions may be taxed as a capital gain with potential BADR — but combined with the prior corporation tax, the effective rate approaches 50–55% on the full gain).
For agency owners who have incorporated, an asset sale structure should be strongly resisted unless the buyer pays a material price premium to compensate for the additional tax cost. Negotiate the structure — share vs asset — before agreeing the headline price. See how to sell your estate or letting agency for guidance on the transaction process.
Business Asset Disposal Relief: The Qualifying Conditions
BADR reduces the CGT rate to 18% on up to £1 million of qualifying lifetime gains. For estate and letting agency owners selling shares, the qualifying conditions are strict and must be met throughout the two-year period immediately before completion.
You must have been, throughout that two years:
- An officer or employee of the company (director or salaried employee)
- Holding at least 5% of the ordinary share capital
- Holding at least 5% of the voting rights
- Entitled to at least 5% of distributable profits (dividends)
- Entitled to at least 5% of assets on a winding-up
These are the “personal company” conditions. All five must be satisfied for the full two years — not just at completion. An agency owner who transferred shares to a family member, restructured voting rights, or reduced their own economic entitlement to below 5% at any point in the two-year window may not qualify.
BADR eligibility must be confirmed, not assumed. Many agency sellers assume they will qualify because they are the founder-director. The conditions are more technical than that. A specialist tax adviser should confirm eligibility before heads of terms are signed — not after.
For guidance on what is agreed at heads of terms stage, see estate agency heads of terms.
Earn-Out Taxation: Marren v Ingles
Earn-outs are common in lettings agency sales, where the buyer wants assurance that the managed property portfolio — and its associated Annual Management Fee Income — will be maintained after completion.
The leading case on earn-out taxation is Marren v Ingles [1980] 54 TC 76. The House of Lords held that where part of the sale consideration is contingent on future performance, the disposal crystallises at completion. The right to receive the earn-out payment is itself a capital asset — created at completion — and its estimated market value must be brought into the CGT computation in the year of completion.
What this means in practice:
At completion, you compute your gain including an estimated value for the earn-out right. If you receive £400,000 upfront and are entitled to up to £200,000 further depending on AMFI performance over 24 months, an adviser will value the earn-out right at completion — perhaps £140,000 reflecting the probability and timing of receipt. Your CGT at completion is on £540,000 (£400,000 + £140,000). BADR applies to this figure if qualifying conditions are met.
When earn-out payments are actually received, the actual amount is compared to the £140,000 brought in at completion. If you receive the full £200,000, the excess — £60,000 — is a further capital gain in the year of receipt, taxed at standard CGT rates (24%), not BADR rates. By the time earn-out payments arrive, you are no longer a director, no longer hold qualifying shares, and the personal company test cannot be satisfied.
Liquidity planning is critical. CGT on the earn-out right arises at completion — before you have received the earn-out cash. On a large earn-out right, this can produce a material tax liability that falls due on 31 January following the completion tax year, regardless of whether the earn-out has yet been paid. Plan for this at the outset, not after completion.
Non-Compete Payments: Why They Must Not Be Separately Valued
Sale agreements frequently include a restriction preventing the seller from competing with the buyer for a defined period after completion. These covenants are commercially necessary.
What matters for tax is whether separate consideration is allocated to the non-compete covenant in the sale documentation. If it is — if the agreement says “£X for the business assets, £Y for the non-compete” — then the £Y element is taxed as income, not capital. Income tax rates (up to 45%) apply, not CGT rates, and BADR cannot apply to income receipts. The non-compete payment is treated as compensation for agreeing not to work — employment income in substance.
The rule: sellers should not accept any allocation of separate consideration for non-compete covenants. The entire consideration should be allocated to the business assets (goodwill, client data, equipment, contracts). The non-compete is a condition of the sale, not a separately purchased item.
Buyers sometimes propose separate non-compete allocations because it may create a deductible expense for them. This benefit to the buyer is your tax cost. Do not accept it without specialist advice on the after-tax impact.
Vendor Loan Notes
Where a buyer cannot fund the full consideration in cash at completion, they may propose a vendor loan — the seller lends the buyer part of the purchase price, repaid over an agreed period with interest.
CGT treatment of the principal. The loan note is part of your sale proceeds. Its face value (the amount to be repaid) is included in your disposal proceeds at completion, and CGT arises in the completion year on the full amount — including the outstanding loan principal. You are taxed before you receive the cash.
Income tax on interest. Interest received on the vendor loan as it is paid down is taxed as income when received, not as capital. Interest income is not eligible for BADR.
Vendor loans can be acceptable in the right transaction, but the CGT-before-cash timing creates the same liquidity planning requirement as an earn-out. Ensure you have the funds to meet your 31 January CGT payment before committing to a loan-note structure.
CGT Payment Timing
CGT on the sale of a private business is reported and paid through self-assessment. The payment deadline is 31 January following the end of the tax year in which the disposal completes.
If completion occurs on 15 June 2026 (in the 2026-27 tax year), CGT is due by 31 January 2028. That gives you approximately 19 months from completion to pay.
This is longer than the 60-day payment window that applies to residential property disposals, and it is often misunderstood. You do not pay on completion. You file your self-assessment return by 31 January and pay the liability at the same time.
However, this does not mean the tax can be ignored until January 2028. The liability is real and should be quantified immediately after completion — particularly where an earn-out right has created a CGT charge before cash is in hand.
The Timing Rule: Tax Advice Before Heads of Terms, Not After
The single most expensive tax mistake in agency sales is instructing a tax adviser after heads of terms have been agreed. By that point, the key decisions — transaction structure, consideration allocation, earn-out mechanism, non-compete treatment — are largely fixed. The adviser can explain what the tax consequences are; they cannot easily undo them.
Effective tax planning requires at least two years of lead time for BADR conditions. It requires structural decisions before price negotiations. It requires consideration of earn-out valuation methodology before the earn-out mechanism is agreed with the buyer.
Instruct a specialist adviser — one who advises regularly on business sales in the agency sector — before you begin conversations with buyers, not after you have shaken hands on a deal.