Share Purchase Agreement UK: Clauses, Tax and Share Transfer Process
A Share Purchase Agreement (SPA) is a contract setting out the terms on which a buyer acquires shares from an existing shareholder in a company. It records the purchase price, shares being sold, payment arrangements, seller warranties, indemnities, completion requirements and continuing obligations. In a UK share acquisition, the target company remains the same legal entity. Its property, contracts, employees and existing liabilities remain with it.
The buyer acquires the shares and the economic risks associated with owning them, but does not ordinarily become personally liable for the company’s debts. This explains how UK Share Purchase Agreements work, including financial due diligence, pricing mechanisms, Capital Gains Tax, Stamp Duty and Companies House requirements.
What Information Does a UK Share Purchase Agreement Contain?
A Share Purchase Agreement identifies the parties, shares, consideration, contractual protections and procedures required to complete the transaction.
| SPA attribute | Information recorded |
| Buyer | Person or entity acquiring shares |
| Seller | Existing shareholder disposing of shares |
| Target company | Company whose shares are being purchased |
| Shareholding | Number and class of shares transferred |
| Purchase price | Fixed amount or agreed calculation mechanism |
| Warranties | Contractual statements about the company |
| Indemnities | Compensation provisions for defined liabilities |
| Completion | Payment, documents and other required actions |
| Governing law | Law governing the transaction |
| Post-completion terms | Continuing obligations and claim procedures |
Is a Written SPA Compulsory for Every Share Transfer?
No. UK law does not require a detailed SPA for every private company share transfer. However, an SPA is particularly useful when a company has employees, bank loans, commercial contracts, property or outstanding tax obligations. A stock transfer form records the transfer but does not provide equivalent contractual protection.
How Does a UK Private Company Share Sale Progress?
A typical share sale moves through negotiations, due diligence, contract preparation, signing, completion and share registration.
| Stage | Main activity |
| Heads of terms | Agree indicative price, structure and timetable |
| Due diligence | Examine financial, tax and legal information |
| SPA drafting | Negotiate payment terms, warranties and indemnities |
| Signing | Execute the agreement |
| Completion | Make required payments and deliver documents |
| Registration | Update the company’s share ownership records |
Signing and completion may happen on the same day or at separate times.
What Should Heads of Terms Establish?
Heads of terms identify the proposed consideration, shares being acquired, expected timetable and any conditions affecting the transaction. They are often largely non-binding, but exclusivity, confidentiality and certain costs provisions can create enforceable obligations. The document should specify which provisions are intended to be legally binding.
How Is the Purchase Price Determined?
The purchase price can be fixed or adjusted using the company’s cash, debt, working capital and financial performance.
| Pricing mechanism | How it works |
| Fixed price | Consideration agreed in advance |
| Locked-box | Price established using accounts at an agreed historical date |
| Completion accounts | Final price adjusted using completion-date figures |
| Deferred consideration | Fixed payment made after completion |
| Earn-out | Additional consideration linked to future performance |
| Retention | Part of the price withheld for specified risks |
| Escrow | Funds held by an independent party until release conditions are satisfied |
What Is the Difference Between Locked-Box and Completion Accounts?
A locked-box arrangement fixes the price using a specified historical balance sheet. The seller normally agrees to restrictions on extracting value before completion. Completion accounts adjust the final price after completion according to an agreed calculation, commonly involving cash, debt and working capital. The SPA should define every adjustment, the accounting policies used, and the procedure for resolving disagreements.
How Do Earn-Outs Affect the Final Consideration?
An earn-out makes additional payments dependent on agreed performance targets, such as revenue or EBITDA. For example, a seller may receive £400,000 at completion and another £100,000 if the company achieves an agreed profit target over the following year. The SPA should define the measurement period, permitted accounting adjustments and the buyer’s responsibilities when managing the company during that period.
How Can Financial Information Support a Share Valuation?
A business may be valued on an enterprise-value basis before adjustments for cash, financial debt and agreed working-capital items.
| Illustrative equity valuation | Amount |
| Agreed enterprise value | £800,000 |
| Add qualifying cash | £60,000 |
| Deduct financial debt | −£110,000 |
| Indicative equity value | £750,000 |
This simplified example assumes there are no additional working-capital, debt-like, or transaction adjustments. The actual price depends on the SPA definitions and agreed valuation method.
What Financial and Tax Due Diligence Should a Buyer Perform?
Financial and tax due diligence examines the target company’s recorded results, outstanding liabilities and tax compliance before acquisition. Buyers commonly request annual accounts, management accounts, bank statements, customer balances, supplier balances and loan agreements. Tax records should include Corporation Tax returns, VAT returns, payroll information and relevant HMRC correspondence.
How Can Due Diligence Reveal Undisclosed Liabilities?
A buyer might discover that £25,000 of reported trade receivables relates to disputed customer invoices. The buyer can then reconsider the valuation, request additional evidence or negotiate a contractual protection. Tax due diligence may identify unpaid VAT, unresolved Corporation Tax enquiries, PAYE discrepancies or tax liabilities arising before completion. A quality of earnings review can also identify non-recurring income or expenses that distort reported profits.
How Do Warranties and Indemnities Protect a Share Buyer?
Seller warranties provide contractual statements about the company’s condition. Indemnities allocate financial responsibility for defined liabilities.
| Protection | Main function |
| Title warranty | Confirms the seller’s rights to the shares |
| Accounts warranty | Addresses accuracy of financial reporting |
| Tax warranty | Covers specified tax compliance statements |
| Employment warranty | Addresses employment obligations |
| Litigation warranty | Covers disclosed or undisclosed disputes |
| Specific indemnity | Allocates defined losses or liabilities |
| Tax covenant | Allocates specified historical tax liabilities |
A warranty breach may support a damages claim. An indemnity creates a separate contractual recovery right, subject to its wording.
How Does a Disclosure Letter Affect Warranty Claims?
A disclosure letter identifies exceptions to the seller’s warranties. Specific disclosures may describe an existing customer dispute, an HMRC enquiry or a particular contractual liability. A properly disclosed matter can limit the seller’s warranty liability to the extent provided by the SPA. Merely uploading documents to a data room does not necessarily satisfy the agreed disclosure standard.
What Limits Can Apply to Seller Liability?
SPAs may impose an aggregate financial cap, minimum claim value, claims basket or notification deadline. Fundamental warranties, tax claims and specific indemnities may have different limits from general business warranties. There is no universal UK statutory percentage that every SPA must apply to warranty liability.
Which UK Taxes Apply to a Share Purchase?
A UK share purchase may create Stamp Duty or Stamp Duty Reserve Tax for the buyer, while the seller may face Capital Gains Tax or Corporation Tax. The tax treatment depends on the type of shares, transaction method, seller, and available reliefs.
When Is Stamp Duty Payable on a Stock Transfer Form?
Stamp Duty is generally charged at 0.5% of consideration, rounded up to the nearest £5, when a qualifying stock transfer form records a purchase for more than £1,000.
For example, a chargeable £100,000 share purchase normally results in £500 Stamp Duty. Where duty applies, the buyer must normally submit the signed and dated stock transfer form and pay the tax within 30 days.
How Do You Submit a Stock Transfer Form to HMRC?
HMRC accepts an electronic copy or scan of the signed and dated form by email.
The current procedure is:
- Complete and sign the stock transfer form.
- Calculate any Stamp Duty due.
- Pay HMRC within 30 days of the form being signed and dated.
- Email the form and required payment information to HMRC’s Stamp Duty service.
- Retain HMRC’s confirmation and the original executed instrument for the company records.
The previous physical stamping system has been permanently withdrawn. Where the applicable duty has been paid, HMRC treats the instrument as duly stamped for the relevant purposes.
What Capital Gains Tax Can an Individual Shareholder Pay?
For 2026–27, the ordinary individual Capital Gains Tax rates on share gains are generally 18% and 24%. The taxable gain normally reflects disposal proceeds less allowable acquisition costs, relevant expenses, capital losses and available reliefs. An individual selling shares for £200,000 does not automatically have a £200,000 taxable gain. The original acquisition cost must be considered.
What Is the Business Asset Disposal Relief Rate in 2026–27?
Qualifying disposals made from 6 April 2026 are subject to an 18% Business Asset Disposal Relief (BADR) rate. The current lifetime limit is £1 million of qualifying gains. Relief on shares generally depends on personal-company ownership conditions, qualifying voting and economic rights, officer or employee status and the relevant holding period. HMRC announced on 29 October 2026 a proposed reduction of the BADR lifetime limit to £500,000 for qualifying disposals from 6 April 2027, subject to legislation.
Can Signing Before April 2027 Preserve the £1 Million BADR Limit?
Not automatically. The proposed anti-forestalling provisions address certain unconditional contracts entered into before 6 April 2027 but completed afterwards. The proposals contain conditions concerning the purpose of the contract, connected parties and specified statements. Sellers should not assume that signing early secures the present lifetime limit.
Is VAT Charged on a Share Purchase or Business Asset Sale?
A sale of existing shares in the course of business is generally VAT-exempt. A sale of business assets may involve VAT, unless an applicable exception or special rule applies.
| Transaction | VAT treatment |
| Sale of existing shares | Generally VAT-exempt when made as a business transaction |
| Sale of individual business assets | VAT treatment depends on the assets and circumstances |
| Qualifying transfer of a going concern | Outside the scope of VAT |
| Issue of new shares to raise capital | Generally not a supply for VAT purposes |
A share purchase normally does not transfer the company’s underlying assets to a new owner. The company continues to own them. Under a qualifying transfer of a going concern (TOGC), business assets move to a purchaser who continues the relevant business activity. Where all statutory conditions are met, TOGC treatment is mandatory rather than optional.
How Are Shares Legally Transferred to the Buyer?
Completing an SPA and registering the buyer as a shareholder are separate legal steps. Under section 770 of the Companies Act 2006, a company generally requires a proper instrument of transfer before registering a transfer, subject to statutory exceptions.
Under section 771, the company must register a properly lodged transfer or notify the transferee of refusal and reasons as soon as practicable, and within two months. The company must also have the legally required information for the transferee’s entry in its register of members before registering the transfer.
Which Documents Are Usually Required at Completion?
Common documents include a stock transfer form, relevant share certificates, board minutes, disclosure letter, tax covenant and agreed completion deliverables. Additional documents may include director resignation letters, consultancy agreements, or escrow instructions. The exact requirements depend on the target company’s articles and the negotiated terms.
When Does the Buyer Become a Registered Member?
The buyer becomes a registered member when their name is entered in the company’s register of members, subject to the applicable statutory arrangements. The company must consider its articles, transfer restrictions, required transferee information and Stamp Duty documentation. A transfer of existing shares does not normally require an immediate Companies House allotment filing. Shareholder changes and changes involving people with significant control may require separate statutory reporting.
What Can Delay the Completion of an SPA?
Completion may depend on conditions precedent, including regulatory approvals, finance arrangements, shareholder consents or contractual permissions. The SPA should identify which conditions must be satisfied, who is responsible for satisfying them and when completion must take place.
What Is a Long-Stop Date?
A long-stop date is the agreed deadline for satisfying or waiving the outstanding completion conditions. If the deadline passes, the SPA may permit termination or extension according to its terms. A party’s contractual breach can have different consequences from a condition failing for reasons outside that party’s control.
How Does a Share Purchase Differ From an Asset Purchase?
A share purchase transfers ownership of company shares. An asset purchase transfers agreed business assets and any liabilities that pass by contract or operation of law.
| Attribute | Share purchase | Asset purchase |
| Buyer acquires | Shares in target company | Specified assets |
| Target legal entity | Remains the same | Assets change ownership |
| Existing debts | Remain liabilities of target company | Depend on transfer terms and applicable law |
| VAT | Share transfer generally exempt | VAT or TOGC rules may apply |
| Stamp taxes | Stamp Duty or SDRT may apply | SDLT or other transaction taxes may apply |
| Employment | Employer normally unchanged | TUPE may apply |
| Commercial contracts | Remain with target, subject to change-of-control terms | Assignment or novation may be needed |
A share purchase does not ordinarily make the buyer personally liable for all target-company debts. However, those liabilities affect the value and financial risks of the acquired shares. An asset purchase does not necessarily exclude every historical liability, particularly where legislation transfers obligations.
Which Obligations Continue After Completion?
An SPA can contain warranties, indemnities, confidentiality provisions and restrictive covenants that continue after completion. A non-compete clause may restrict defined competitive activities. Non-solicitation provisions may restrict attempts to attract specified customers or employees.Enforceability depends on the legitimate business interest protected and whether the restriction is reasonable in scope and duration.
How Does an SPA Differ From a Shareholders’ Agreement?
An SPA governs a share acquisition. A shareholders’ agreement governs continuing relationships between shareholders. A shareholders’ agreement commonly addresses voting rights, dividends, reserved matters and future share transfers. The SPA may continue to operate after completion through warranty, indemnity and other surviving provisions.
Frequently Asked Questions
No. A detailed SPA is not mandatory for every private company share transfer. It is commonly used when the buyer and seller need contractual protections beyond the stock transfer instrument.
The buyer’s solicitor commonly prepares the first draft in a bilateral acquisition. In a competitive sale process, the seller may provide the draft.
The tax liabilities normally remain with the target company rather than becoming the buyer’s personal liabilities. However, the buyer acquires shares in a company exposed to those liabilities.
Yes, where the requirements for a binding contract are satisfied. If signing and completion occur separately, the agreement normally sets out the conditions and obligations governing the period between them.
No. A stock transfer form records the legal transfer but does not ordinarily include financial warranties, tax indemnities or the detailed commercial protections found in an SPA.
Sales of existing shares made in the course of business are generally VAT-exempt. They are not treated as transfers of the target company’s underlying business assets for TOGC purposes.
Get Accounting and Tax Support for a Share Acquisition
A share acquisition requires reliable financial information, an assessment of existing tax liabilities and a clear understanding of the purchase-price calculation. Tilly & Cooper Corporate Accountants can assist with statutory accounts, financial-record reviews, Corporation Tax matters and tax calculations relevant to buying or selling UK company shares.
To discuss the accounting and tax work required, provide the target company’s registration number, latest financial statements, proposed consideration and anticipated completion date. A suitably qualified solicitor should prepare or review the SPA, share-transfer documentation and contractual protections. Planning a UK company share acquisition or disposal? Explore our annual accounts preparation service or contact Tilly & Cooper to arrange a consultation.
