Buying or selling shares in a business is not a handshake deal. It is one of the most legally significant transactions a business owner will ever enter, and the document that governs it determines what you own, what you owe, and what happens if things go wrong. That document is the share purchase agreement. Getting it right matters more than most buyers and sellers realise until it is too late.
What Is a Share Purchase Agreement
A share purchase agreement (SPA) is a legally binding contract between a seller and a buyer that sets out the terms on which shares in a company are transferred. It records the price, the conditions that must be met before the deal completes, the promises each party is making about the business, and the protections available if those promises turn out to be wrong.
The SPA is the central document in any share sale. Everything negotiated between the parties, from the valuation to the liability caps, lives in this agreement. Without one, there is no legal framework governing the transaction and no route to recourse if something goes wrong after the shares change hands.
When Do You Need One
Any transaction involving the sale or transfer of shares in a private limited company requires a share purchase agreement. This includes founder exits, management buyouts, investor share sales, acquisitions of competitor businesses, and partial stake transfers between existing shareholders.
The SPA is not a formality to be dealt with at the end of a deal. It needs to be drafted, negotiated, and agreed before completion. The terms in the agreement shape the entire transaction, and leaving it too late to negotiate key provisions is one of the most common and costly mistakes in share sales.
What a Share Purchase Agreement Includes
Purchase Price and Payment Terms
The SPA sets out the total consideration being paid for the shares, how and when it will be paid, and any adjustments that apply after completion. Payment structures in UK share sales vary significantly. Some deals involve a fixed price paid in full on completion. Others include deferred consideration, where part of the price is paid over time, or earn-out mechanisms, where the final amount depends on the future performance of the business.
Each structure carries different risk for buyer and seller. Earn-outs create potential for dispute if the performance metrics are not precisely defined. Deferred consideration depends on the financial standing of the buyer after completion. The payment terms need to reflect the deal and be drafted with enough precision to prevent disagreement later.
Conditions Precedent
Conditions precedent are the things that must happen before the deal can complete. They might include regulatory approvals, third-party consents, the resolution of a specific legal issue identified during due diligence, or the departure of a key individual from the business.
Where conditions precedent are included, the SPA will set a longstop date by which they must be satisfied. If they are not met by that date, either party may have the right to walk away. Conditions precedent are common in complex transactions and in deals involving regulated businesses where approval from the Financial Conduct Authority or another regulatory body is required before ownership can transfer.
Warranties and Indemnities
Warranties are statements the seller makes about the state of the business at the point of sale. They cover the financial position, the contracts, the employees, the IP, the regulatory standing, and the litigation history of the company. If a warranty turns out to be inaccurate, the buyer has a legal claim against the seller.
Indemnities go further. An indemnity is a promise by the seller to compensate the buyer pound for pound if a specific liability materialises after completion. Indemnities are typically used where a known risk has been identified during due diligence but cannot be resolved before the deal completes. The scope of both warranties and indemnities, the liability caps, the time limits on claims, and the thresholds below which claims cannot be brought are all heavily negotiated provisions in any SPA.
Disclosure Letter
The disclosure letter is the seller’s formal response to the warranties. It sets out any exceptions, qualifications, or matters that the seller is disclosing against the warranty statements. A matter that is properly disclosed cannot later form the basis of a warranty claim by the buyer.
The disclosure process is one of the most important and most misunderstood parts of a share sale. Sellers who treat it as a tick-box exercise and fail to make full and proper disclosures leave themselves exposed to claims after completion. Buyers who do not scrutinise the disclosure letter carefully may find their warranty protection significantly reduced.
Restrictive Covenants
Restrictive covenants in a share purchase agreement prevent the seller from competing with the business they have just sold, poaching its clients, or soliciting its employees for a defined period after completion. They protect the value of what the buyer has acquired.
Under English law, restrictive covenants must be reasonable in scope, duration, and geographic reach to be enforceable. A blanket non-compete with no time limit will not hold. The covenants need to be drafted to reflect the specific business and the actual competitive risk the buyer faces, not copied from a generic template.
Completion Mechanics
The completion mechanics section sets out exactly what happens on the day the deal closes. It specifies which documents are exchanged, what board resolutions are passed, how the consideration is transferred, and what confirmations each party must provide before the shares formally change hands.
Poorly drafted completion mechanics create confusion and delay on the day. In complex transactions involving multiple sellers or simultaneous conditions, the mechanics need to be sequenced carefully to ensure that nothing transfers until everything required has been delivered.
Is a Share Purchase Agreement Legally Binding
Yes. Once signed by all parties, a share purchase agreement is a legally binding contract enforceable under English law.
For buyers: You are bound by the price and payment structure you agreed, the conditions you accepted, and any post-completion obligations in the agreement. If you fail to complete without a valid legal reason, the seller can pursue you for damages or specific performance.
For sellers: You are bound by the warranties you gave and the indemnities you provided. A warranty claim can arise months or years after the deal closes if a misrepresentation is later discovered. The liability caps and limitation periods negotiated in the SPA determine the extent of your ongoing exposure.
How Blackmont Legal Helps
A share purchase agreement is only as strong as the drafting behind it. A poorly worded warranty schedule, a vague earn-out mechanism, or an unenforceable restrictive covenant can cost significantly more to fix after completion than it would have cost to get right in the first place.
At Blackmont Legal, we advise buyers and sellers on share purchase agreements across a range of sectors and deal sizes. We draft SPAs that protect your position, negotiate the terms that matter most to your deal, and manage the disclosure process so both parties understand exactly what they are signing. We also advise on deal structure, helping clients choose between a share sale and an asset sale based on their specific commercial and tax position.
