Buying a Business in the UK: Legal Due Diligence and Key Contracts

Buying a business can be an exciting shortcut to growth.

Instead of spending months (or years) proving product-market fit, building systems, and finding customers, you’re stepping into something that already works. But the flip side is simple: you’re also stepping into whatever doesn’t work.

That’s why the legal side of buying a business matters so much. Done properly, due diligence and the right contracts can help you buy with confidence, price the deal fairly, and avoid nasty surprises after completion.

Below, we’ll walk you through what “legal due diligence” actually means in practice, what contracts you’ll typically need, and the key legal risks to manage when you’re buying a business in the UK as an SME or startup.

What Does “Buying a Business” Actually Mean (Asset Sale vs Share Sale)?

When people talk about buying a business, they’re usually referring to one of two deal structures:

1) Asset Purchase (Buying the Business Assets)

In an asset purchase, you buy the assets you need to run the business. This might include:

• equipment and stock
• customer contracts and supplier agreements (where transferable)
• intellectual property (brand, software, designs, domain names)
• goodwill (the value of the business reputation and customer base)

You don’t automatically take on the company itself (and all of its historic liabilities) - but you do need to be careful. Some liabilities can still transfer or follow the business in certain situations (for example, under TUPE, or if you agree to assume particular obligations), and you may inherit practical problems (like a key supplier refusing to novate their contract). You should also take tax and structuring advice early, as the way assets and goodwill are treated can affect the overall deal.

2) Share Purchase (Buying the Company Shares)

In a share purchase, you buy the shares in the company that owns the business. That means the company stays the same legal entity - you just become the owner.

This is often simpler operationally because the company continues to hold:

• customer and supplier contracts
• leases and property arrangements
• licences and permits (where they remain valid after a change of ownership)

But it also means you’re buying the company “warts and all”, including historic liabilities (for example, unresolved disputes, compliance issues, tax risks, or problematic employment situations).

If you’re buying shares, it’s common to document the deal with a Share Sale Agreement.

So Which Structure Is Better?

There’s no universal “best” option - it depends on what you’re buying, what risks you’re willing to accept, and what the seller is prepared to do.

As a general guide:

• Asset sales can help ring-fence some historic liabilities, but they can be more complex to implement (because you may need consents, novations, new leases, new licences, and transfers of IP).
• Share sales are often operationally smoother, but due diligence and contractual protections become even more important because liabilities stay inside the company.

Legal Due Diligence: What You Should Check Before You Buy

Legal due diligence is the process of checking what you’re actually buying, what obligations come with it, and whether there are any red flags that should affect the price or your decision to proceed.

It can feel like a lot - but it’s better to discover issues before you’re committed than after you’ve paid the purchase price.

For SMEs and startups, legal due diligence usually focuses on practical risk: “What could blow up later, and what’s that likely to cost?”

If you want a structured approach, a Legal Due Diligence Package can help you cover the key areas without missing the basics.

Company And Corporate Checks

If you’re buying shares, you’ll typically want to confirm:

• the company is validly incorporated and in good standing
• who owns the shares, and whether there are any third-party rights over them (charges, options, restrictions)
• the company has the authority to sell (board/shareholder approvals where needed)
• any unusual constitutional provisions (for example, pre-emption rights that complicate the sale)

Even for asset sales, it’s worth checking the seller’s corporate position so you know they have the right to sell what they’re offering.

Commercial Contracts (Customers, Suppliers, Partners)

Contracts are often where the “real value” sits - and also where the most unpleasant surprises hide.

You’ll want to review key contracts to understand:

• change-of-control clauses (which may allow termination if the company is sold)
• assignment/novation restrictions (critical in asset sales)
• price increases, minimum purchase commitments, or exclusivity obligations
• termination rights and notice periods
• service levels and liability caps (particularly in B2B service businesses)

This is also a good moment to sanity-check whether the business relies on informal arrangements that aren’t documented. If key revenue depends on handshake deals, you may be buying uncertainty.

In many deals, it’s smart to build contract review into your transaction timetable using a Contract Review process so you can spot issues early enough to renegotiate (or walk away).

Employment And TUPE Risk

If the business has staff, this is a major due diligence area.

In an asset purchase, employees may transfer automatically to you under TUPE (the Transfer of Undertakings (Protection of Employment) Regulations 2006). In plain English: you can end up inheriting employees on their existing terms, along with associated liabilities.

Key things to check include:

• who is employed, their roles, and whether they’re genuinely employees or contractors
• salary, benefits, commission structures, bonuses, and holiday entitlement
• any disputes, grievances, disciplinary matters, or tribunal claims
• restrictive covenants (non-compete / non-solicit) and whether they’re enforceable

If you’re planning to retain staff (or hire replacements), having robust Employment Contract documentation and a clear onboarding plan will help protect you from day one after completion.

Property, Leases, And Premises

If the business operates from a physical location, you’ll want to understand the legal basis for occupation, such as:

• a commercial lease
• a licence to occupy
• a serviced office agreement

Important questions include:

• Can the lease be assigned to you, and does it require landlord consent?
• Are there rent reviews, break clauses, or unusual repair obligations?
• Is there a rent deposit, and will it be transferred/refunded?
• Are there any arrears or disputes with the landlord?

A property issue can turn a “great deal” into an expensive headache, especially if your business model depends on that location.

Intellectual Property And Brand Ownership

For startups and tech-enabled SMEs, IP can be the main reason you’re buying the business in the first place.

Due diligence should check:

• what IP exists (trade marks, domains, software, designs, content, databases)
• whether the seller actually owns it (or whether it was created by a contractor who never assigned rights)
• whether any third-party licences are required (and transferable)
• any infringement claims or takedown notices

If there are gaps in ownership, you may need an IP assignment or new licences as a condition of completion.

Data Protection And GDPR Compliance

If the business collects customer data (and most do), you’re inheriting data protection risk.

In due diligence, you’ll want to understand:

• what data is collected and where it’s stored (CRM, email marketing tools, cloud storage)
• whether the business has a lawful basis for processing personal data
• whether it has appropriate privacy notices and retention practices
• whether there have been any data breaches or ICO complaints

If customer databases or marketing lists are transferring, check how the data will be lawfully transferred to you and used after completion (including GDPR transparency requirements and, where relevant, PECR rules for electronic marketing). After completion, you may need to update customer-facing documents such as a Privacy Policy to reflect the new ownership and how data is used.

The Key Contracts You’ll Typically Need When Buying a Business

Due diligence tells you what you’re dealing with. The contracts are what protect you once you commit to the purchase.

While every deal is different, most UK transactions involve some combination of the following documents.

Heads Of Terms (Or Term Sheet)

This is the “in principle” document that sets out the commercial deal terms before lawyers draft the long-form agreements.

Heads of Terms often cover:

• price and payment structure (including earn-outs)
• what’s included in the sale
• key conditions (for example, financing, landlord consent, due diligence)
• exclusivity period (so the seller can’t shop your offer around)
• confidentiality

Even when “non-binding”, Heads of Terms are important because they influence everything that follows (and can still contain binding clauses like confidentiality or exclusivity if drafted that way).

Confidentiality / NDA

Sellers usually require an NDA before sharing sensitive financials, customer lists, or supplier details.

This matters for buyers too. If you walk away, you don’t want to be accused of misusing information - and if you proceed, you want clear boundaries around what can be disclosed to investors, lenders, and advisers.

Business Sale Agreement (Asset Purchase Agreement)

If you’re buying assets, the core contract is usually a business sale agreement. This is where the “what exactly are we buying?” question gets answered properly.

A well-drafted Business Sale Agreement often includes:

• a detailed list of assets being sold (and excluded assets)
• how contracts transfer (assignment/novation steps)
• IP transfer provisions
• employee transfer/TUPE provisions (where applicable)
• warranties and indemnities
• completion mechanics (what happens on the completion date)

Share Purchase / Share Sale Agreement

If you’re buying shares, the key contract is usually a share sale/purchase agreement.

This agreement typically covers:

• the shares being sold and purchase price
• warranties about the company’s status and operations
• limitations on the seller’s liability (time limits, financial caps, disclosure rules)
• conditions precedent (for example, lender approval)
• completion steps (board resignations, Companies House filings, transfer forms)

In SME deals, warranties and disclosure are often where most of the negotiation happens - because that’s how the risk is allocated between buyer and seller.

Disclosure Letter

A disclosure letter is the seller’s opportunity to qualify the warranties by disclosing issues (for example, “Yes, we have this supplier contract, but it’s in dispute”).

For buyers, this document is crucial because it affects what you can claim later if a warranty turns out to be untrue.

For sellers, it’s also critical because it helps reduce the risk of post-completion claims.

Completion Checklist

Completion is rarely “sign and done”.

There are usually multiple moving parts that must happen on or before completion (funds, board minutes, resignation letters, IP assignments, lease documents, releases of guarantees, etc.).

A Completion Checklist helps you track those deliverables so you don’t miss something that later becomes a legal or operational problem.

Transitional Arrangements (If The Seller Is Helping You Handover)

Many SME acquisitions involve a handover period where the seller helps you transition supplier relationships, customer accounts, and internal know-how.

Don’t leave this as a vague promise.

Instead, document it clearly (often through a short consultancy arrangement or services agreement) covering:

• what support will be provided
• how long it lasts
• what it costs (if anything)
• confidentiality and IP ownership

Common Legal Red Flags When Buying a Business (And How To Handle Them)

Most deals have at least a few “warts”. The goal isn’t perfection - it’s knowing what you’re buying and making sure the contract reflects that reality.

Here are some common red flags we see when SMEs and startups are buying a business in the UK.

Unclear Ownership Of Key Assets

If the seller can’t clearly prove ownership of IP, equipment, or domain names, that’s a problem.

How to handle it:

• require evidence of title/ownership
• make IP assignment a completion deliverable
• use warranties and indemnities for gaps you can’t fully resolve before completion

Customer Concentration Risk

If 60–80% of revenue comes from one or two customers, the value of the deal can evaporate if they leave after completion.

How to handle it:

• review customer contracts for termination rights and change-of-control clauses
• consider earn-out structures (so price depends on future performance)
• build in conditions precedent if a key customer consent is required

Employment Liabilities And TUPE Surprises

Employment disputes can be expensive and time-consuming, and TUPE can limit your ability to change terms quickly.

How to handle it:

• request full employee liability information (and get it in writing)
• factor in accrued holiday pay, bonuses, and commission liabilities
• build clear TUPE provisions into the sale documents (especially for asset deals)

Compliance Gaps (Regulatory, Trading Standards, Consumer Law)

If you’re buying a consumer-facing business, compliance issues can impact refunds, advertising claims, and product quality obligations under the Consumer Rights Act 2015.

How to handle it:

• review customer terms, refund processes, and complaint handling
• check whether licences/registrations exist and are valid
• consider warranty protection and a retention amount (holding back part of the price)

Key Takeaways

• “Buying a business” usually means either an asset purchase or a share purchase, and the legal risk profile is different for each.
• Legal due diligence helps you confirm what you’re buying, uncover liabilities, and identify issues that should impact price or deal structure.
• Pay close attention to contracts, employees (including TUPE), property/leases, IP ownership, and GDPR/data protection.
• The key legal documents commonly include Heads of Terms, an NDA, the main sale agreement (asset or shares), a disclosure letter, and a completion checklist.
• Red flags aren’t always deal-breakers - but they should be addressed with clear contractual protections (warranties, indemnities, conditions, and completion deliverables).
• Don’t DIY business acquisition contracts: they need to be tailored to your deal, your risk tolerance, and how the business actually operates.

If you’d like help buying a business, you can reach us at 08081347754 or team@sprintlaw.co.uk for a free, no-obligations chat.