TRW & Co · Corporate & Commercial
Mergers and Acquisitions Lawyers in London
M&A lawyers London buyers and sellers instruct structure the deal, run due diligence, negotiate the sale agreement and secure clearances. In 2026 the regulatory gates matter as much as price: national security screening can void a deal, CMA thresholds were reset in 2025, and the Takeover Code now applies to a narrower group of companies.
Key pointUnder the National Security and Investment Act 2021, a notifiable acquisition completed without approval is void, so national security screening belongs before heads of terms, not after signing.
At a glance
Voidness under NSIA
Acquiring control of an entity in one of 17 sensitive sectors needs approval first; completing without it makes the acquisition void under section 13.
New CMA thresholds
Since 1 January 2025 the CMA can review deals where target UK turnover exceeds £100 million, plus a new hybrid test and a £10 million safe harbour.
Narrower Takeover Code
From 3 February 2025 the Code mainly covers UK companies with securities traded on UK markets, with a transitional period running to 3 February 2027.
Stamp duty on shares
Buying shares in a UK company usually attracts 0.5% stamp duty or SDRT on the price; asset deals instead raise SDLT on property and VAT questions.
Scheme or offer
A scheme needs 75% by value and a majority in number of each class voting, plus court sanction; an offer reaching 90% allows squeeze-out.
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What M&A lawyers London buyers and sellers instruct actually handle
M&A lawyers London clients instruct handle the legal side of buying, selling and combining businesses: structuring the deal, running or answering due diligence, negotiating the sale agreement, securing regulatory clearances and getting the transaction to completion. In England and Wales the work sits on the Companies Act 2006, contract law, tax legislation and a growing set of clearance regimes, from merger control to national security screening.
Most UK deals are private: one company buys the shares or assets of another privately owned business. Public M&A, where the target's shares trade on a UK market, adds the Takeover Code and a far more rigid timetable. Both share the same commercial questions: what exactly is being bought, what is it worth, and who bears the risk of what nobody yet knows.
This page explains the framework, the structural choices, the process, the key documents and the mistakes that most often move price or delay completion. For the wider corporate context see our corporate solicitors page.
The legal and regulatory framework for UK M&A
There is no single M&A statute. A private acquisition is primarily a contract, so the share purchase agreement (SPA) or asset purchase agreement is the main source of the parties' rights. Statute supplies the corporate mechanics, the tax consequences and the regulatory gates.
Company law
The Companies Act 2006 governs share transfers, shareholder approvals, financial assistance (now prohibited only for public companies), and schemes of arrangement under Part 26. A scheme needs approval from a majority in number representing 75% in value of each class of members voting, followed by court sanction. A contractual takeover offer that reaches 90% of the shares it relates to allows the bidder to squeeze out the minority under section 979.
The Takeover Code
The Takeover Panel administers the Takeover Code. Since 3 February 2025 the Code applies mainly to companies registered in the UK, Channel Islands or Isle of Man whose securities are admitted to a UK regulated market, a UK multilateral trading facility or a Channel Islands or Isle of Man exchange, and to companies that were so listed in the previous two years. A two-year transitional period for companies previously caught by the old residency test runs to 3 February 2027.
Two rules shape every bid. Under Rule 2.6, once a potential offeror is publicly identified it has until the 28th day after that announcement to announce a firm offer or walk away, unless the Panel extends the deadline. Under Rule 9, a person who acquires interests carrying 30% or more of the voting rights must normally make a mandatory cash offer for the rest. Our public takeovers page covers the regime in detail.
Clearance regimes
| Regime | Trigger (summary) | Consequence of getting it wrong |
|---|---|---|
| National Security and Investment Act 2021 | Acquiring control of an entity active in one of 17 sensitive sectors (mandatory); any deal raising security risk (call-in) | Notifiable deal completed without approval is void; criminal and civil penalties |
| CMA merger control | Target UK turnover above £100m; 25% share of supply; or the hybrid test (33% share and £350m UK turnover for one party) | Voluntary regime, but the CMA can investigate after completion and impose hold-separate orders |
| FCA change in control | Acquiring or increasing control of an FCA-authorised firm (Part XII FSMA 2000) | Criminal offence to acquire control without approval |
| Takeover Code | Offer for a company within the Panel's jurisdiction | Panel sanctions; mandatory offer obligations |
| Sector regulators | Deals involving energy, telecoms, water, aviation and similar licensed activities | Licence conditions breached; approvals refused |
The CMA thresholds introduced by the DMCCA apply to deals completed, or Phase 1 investigations started, on or after 1 January 2025. The share-of-supply test does not apply where each party's UK turnover is below £10 million. Our merger control and foreign investment and NSIA teams handle filings.
Key structuring decisions
The deal structure determines tax, risk allocation and timetable. These are the decisions experienced M&A lawyers London clients rely on make early.
Share purchase or asset purchase
In a share purchase the buyer acquires the company with all its history, including unknown liabilities. Contracts, licences and employees stay where they are, so third-party consents are needed only where change-of-control clauses bite. Stamp duty is generally charged at 0.5% on the price for shares transferred by stock transfer form, or Stamp Duty Reserve Tax electronically.
In an asset purchase the buyer chooses which assets and liabilities to take. Contracts must be novated or assigned, property transferred, and employees move automatically under the TUPE Regulations 2006. Sellers usually prefer a share sale for tax reasons; buyers often prefer assets for risk reasons. Our article on share purchase or asset purchase compares the two.
Locked box or completion accounts
A locked box fixes the price by reference to a historic balance sheet, with the seller promising that no value has leaked to it since that date. It gives price certainty and is popular in competitive sales. Completion accounts adjust the price after completion by reference to actual cash, debt and working capital, which suits buyers when the target's balance sheet is volatile but invites post-completion disputes.
Warranties, indemnities and W&I insurance
Warranties are statements of fact about the target; a breach gives a damages claim subject to disclosure, caps, thresholds and time limits. Indemnities give pound-for-pound recovery for specific known risks, typically tax or litigation. Warranty and indemnity insurance lets the buyer claim against an insurer rather than the seller, allowing a clean exit for sellers such as private equity funds. See our guide to W&I insurance in UK deals.
Public M&A: scheme or offer
For a target within the Takeover Code, the bidder chooses between a scheme of arrangement and a contractual offer. A scheme is run by the target with board support and, once approved by the requisite majorities and sanctioned by the court, binds every shareholder, delivering 100% ownership in one step. It is the usual route for recommended deals.
A contractual offer is made directly to shareholders and is the only practical route for a hostile bid. It gives the bidder more control over the process, but 100% ownership depends on reaching the 90% squeeze-out level. Bidders must also have cash confirmation in place before announcing a firm offer, which means financing has to be committed early. The choice affects timetable, stamp duty, deal certainty and how competing bidders can intervene.
The SPA does not make a business safer; it decides who pays when something that was already wrong comes to light.
The deal process and timeline
Private deals typically follow the sequence below. Regulatory reviews and diligence findings, not drafting, usually set the pace.
- Preparation. The seller tidies the corporate records, resolves known issues and builds a data room. The buyer sets its investment thesis and diligence scope.
- Heads of terms and exclusivity. The parties record price, structure, conditions and timetable, usually non-binding apart from confidentiality, exclusivity and costs.
- Due diligence. Legal, financial, tax and commercial teams review the target. The legal report highlights issues that affect price, require indemnities or need fixing before completion.
- Regulatory screening. NSIA, CMA, FCA and sector-specific triggers are assessed. Where filings are needed, they are prepared in parallel with negotiation, since the NSIA review period alone is 30 working days once a mandatory notice is accepted.
- SPA negotiation and disclosure. The SPA, disclosure letter, tax covenant and ancillary documents are negotiated. The seller discloses against warranties to limit liability.
- Signing. Where conditions are outstanding, the parties sign and then complete later, with interim conduct-of-business restrictions on the target.
- Completion. Conditions are satisfied, the price is paid, share transfers and resignations are delivered, and the buyer takes control.
- Post-completion. Companies House filings, stamp duty, completion accounts or locked-box leakage checks, and integration of employees, contracts and systems.
Key documents and evidence
A well-run transaction relies on a short list of core documents. Knowing what each one does helps decision-makers focus negotiation where it matters.
Share or asset purchase agreement
Sets price, conditions, completion mechanics, warranties, indemnities and limitations. It is the document every later dispute will be argued over.
Disclosure letter
The seller's qualifications to the warranties. General disclosures of the data room are commonly negotiated; specific disclosures must be fair and sufficiently detailed.
Tax covenant
An indemnity from the seller for pre-completion tax liabilities of the target, usually sitting in a schedule to the SPA with its own conduct-of-claims rules.
Due diligence report
A red-flag or full report on the target's constitution, contracts, employees, property, IP, data, disputes and compliance, feeding directly into price and protection.
Transitional services agreement
Where the target relied on group services, the seller continues to provide IT, payroll or premises for a defined period after completion.
Management and restrictive covenant terms
New service agreements, non-compete and non-solicit covenants for selling founders, and earn-out terms where part of the price depends on future performance.
Risks and common mistakes
These issues cause most late-stage price chips, delays and post-completion claims in the deals M&A lawyers London businesses bring to us.
Treating NSIA as a box-ticking exercise
The mandatory regime catches acquisitions of more than 25% of shares or votes in entities carrying on activities in 17 sectors, and some definitions, such as data infrastructure and artificial intelligence, capture businesses that do not think of themselves as sensitive. A notifiable deal completed without approval is void, which means the buyer may not actually own what it paid for. The government confirmed in March 2026 that it will revise several sector definitions, add water as a standalone sector and narrow the AI schedule, so the analysis must be done against the regulations in force at signing.
Weak locked-box leakage protection
In a locked-box deal the buyer's protection is the seller's covenant that no value has leaked since the locked-box date, other than agreed permitted leakage. If permitted leakage is drafted too broadly, or the definition of leakage misses management fees, bonuses or intra-group payments, value can flow to the seller with no remedy. Buyers should check the locked-box accounts carefully, limit permitted leakage to specific, quantified items, and make sure the leakage claim is recoverable pound for pound and not subject to the general warranty caps.
Disclosure that does not actually disclose
Sellers often try to disclose the entire data room generally against all warranties. Buyers resist, and courts expect disclosure to be fair, with sufficient detail to identify the nature and scope of the matter. Disputes over whether something was properly disclosed are among the most common post-completion claims. Both sides should agree the standard of disclosure in the SPA, and sellers should make specific disclosures against particular warranties rather than relying on a blanket reference to the data room.
Ignoring employment and pensions on asset deals
Under TUPE, employees assigned to the transferring business move to the buyer automatically on their existing terms, and both parties have information and consultation duties. Dismissals because of the transfer are automatically unfair unless there is an economic, technical or organisational reason entailing changes in the workforce. Defined benefit pension schemes raise separate issues, because the Pensions Regulator has powers that can reach parties connected with an employer. These need to be priced and allocated in the SPA, not left to post-completion integration. See our TUPE and redundancy page.
Earn-outs without operating rules
Earn-outs bridge valuation gaps but are a frequent source of litigation. Sellers worry the buyer will run the business to depress the earn-out; buyers want freedom to integrate. The SPA needs clear accounting policies, protective covenants on how the business is run during the earn-out period, information rights, an expert determination mechanism for disagreements and a clear treatment of what happens if the buyer sells the business or restructures the group before the earn-out ends.
Screen for NSIA, CMA and FCA change-in-control triggers before heads of terms are signed. If a filing is needed, the timetable, long-stop date, conditions and break provisions all change, and it is far easier to agree that allocation of regulatory risk at the outset than in the final week before signing.
Cross-border M&A: Bangladesh, the Gulf, Europe and Asia
A large share of London M&A involves an overseas buyer, seller or target subsidiary. The SPA is commonly governed by English law with disputes referred to the English courts or to arbitration in London, but local law still governs title to shares, corporate approvals and exchange control in each relevant country.
For Bangladesh, a transfer of shares in a Bangladeshi company must comply with the Companies Act 1994 and be recorded with the Registrar of Joint Stock Companies and Firms. Payments of consideration into or out of Bangladesh are subject to Bangladesh Bank foreign exchange rules, and the Bangladesh Investment Development Authority is relevant to foreign-owned businesses. Our investing in Bangladesh team works with TRW & Co's Dhaka office on these deals.
Gulf, Singaporean and Chinese buyers of UK businesses should expect closer attention under NSIA, particularly in technology, energy and infrastructure. For European targets, separate local merger control and foreign investment filings may be needed in addition to UK clearances. Coordinating every filing under one timetable is a core part of cross-border deal management.
Dispute resolution clauses deserve attention in cross-border deals. An English court judgment may be harder to enforce in some jurisdictions than a London-seated arbitral award, which can be recognised under the New York Convention in most major economies. Choosing the forum with enforcement against the actual counterparty in mind, rather than by habit, is one of the simplest protections a buyer or seller can build into the SPA. Our international arbitration team advises on these clauses.
How TRW & Co helps
TRW & Co's London office is authorised and regulated by the Solicitors Regulation Authority. As M&A lawyers London clients can instruct for private and cross-border deals, we act on the following workstreams.
Buy-side acquisitions
Structuring, due diligence, SPA negotiation, W&I insurance coordination and completion for strategic and financial buyers.
Sell-side and exits
Vendor preparation, data room management, disclosure, auction process documents and negotiating limitations of seller liability. See also buying and selling a business.
Regulatory clearances
NSIA notifications, CMA briefing papers, FCA change-in-control applications and coordinating overseas filings.
Post-completion disputes
Warranty and indemnity claims, completion accounts and earn-out disputes. Where advocacy in the higher courts is required, we instruct specialist counsel.
See the full range of our services on our practices page.
Choosing M&A lawyers in London
When comparing M&A lawyers London firms offer, look beyond headline experience. Ask who will run the deal day to day, how the firm will coordinate tax, employment, pensions and regulatory advice, and how it will manage counterparties and counsel in other jurisdictions. A mid-market cross-border deal often turns on the quality of that coordination rather than on the SPA drafting itself.
Ask too how the firm approaches risk allocation: whether it starts from a buyer-friendly or seller-friendly template, how it uses W&I insurance, and how it prices regulatory risk into long-stop dates and break fees. Good M&A lawyers London advisers will explain these trade-offs in commercial terms rather than legal ones.
Finally, consider continuity. The lawyers who negotiate the SPA should be available to advise on completion accounts, earn-out calculations and any warranty claims, because they understand what was intended when each clause was agreed. That continuity is often worth more than a marginally better first draft.
Checklist for decision-makers
- Structure chosen (shares or assets) with tax advice on both sides of the deal.
- NSIA, CMA, FCA and sector-specific triggers screened before heads of terms.
- Price mechanism agreed, with leakage or completion accounts definitions reviewed by finance.
- Diligence scope set to the real risks of the target, not a generic checklist.
- Warranty, indemnity and limitation package agreed, and W&I insurance considered.
- Employees, pensions and key contracts with change-of-control clauses mapped.
- Overseas approvals, exchange control and title transfer steps confirmed with local counsel.
- Post-completion integration plan and filing list prepared before signing.
To discuss a transaction with M&A lawyers London who can coordinate across Bangladesh, the Gulf and Asia, contact TRW & Co at info@trw.co. For background, read our guide to NSIA mandatory notification.
Frequently asked questions
01Should I buy the shares or the assets of a business?
A share purchase transfers the company with all its history, so contracts, licences and employees stay in place but unknown liabilities come too. An asset purchase lets the buyer pick assets and liabilities, but contracts need consent to transfer, property must be conveyed and employees move automatically under TUPE. Sellers often prefer share sales for tax reasons, while buyers sometimes prefer assets for risk reasons. The right answer depends on tax, liabilities, consents and timetable, and is usually settled at heads of terms.
02What is a locked box and when should I use one?
A locked box fixes the price using a balance sheet at an agreed date before signing. The seller promises that no value has leaked from the target to the seller since then, apart from agreed permitted leakage. It gives certainty and avoids post-completion price adjustments, which is why sellers and private equity funds favour it in competitive processes. Buyers should only accept it where the locked-box accounts are reliable and leakage protection is drafted tightly, with pound-for-pound recovery.
03What does W&I insurance cover?
Warranty and indemnity insurance covers loss from breaches of warranties, and often the tax covenant, that were unknown to the buyer at signing. It lets sellers limit their own liability, which helps clean exits, and gives buyers a creditworthy counterparty. It does not usually cover matters known to the buyer or disclosed, forward-looking warranties, or certain excluded risks identified in diligence. Policies are underwritten on the basis of the buyer's diligence reports, so the quality of diligence directly affects the cover available.
04Does my deal need approval from the government?
It may. The National Security and Investment Act 2021 requires mandatory notification of acquisitions of control in 17 sensitive sectors, including defence, energy, communications, data infrastructure and artificial intelligence. Once a mandatory notice is accepted, the government has 30 working days to clear the deal or call it in for a fuller assessment. Separately, the CMA may review deals meeting its turnover or share-of-supply tests, and the FCA must approve acquisitions of control of authorised firms.
05Which companies are covered by the Takeover Code now?
Since 3 February 2025 the Code applies mainly to companies registered in the UK, Channel Islands or Isle of Man whose securities are admitted to trading on a UK regulated market, a UK multilateral trading facility or a Channel Islands or Isle of Man stock exchange, and to companies that were so traded within the previous two years. Companies that were previously caught only through the old residency test benefit from a transitional period that ends on 3 February 2027.
06How long does a private acquisition take?
It varies with the size and complexity of the target, the depth of diligence, and whether regulatory approvals are needed. A small owner-managed business with clean records can move quickly; a deal needing an NSIA notification or FCA change-in-control approval must allow for those review periods between signing and completion. The best way to shorten the timetable is preparation: a seller with reconciled corporate records and a well-organised data room removes most of the avoidable delay.
07Can TRW & Co act on deals involving Bangladesh?
Yes. TRW & Co's London office advises on the English law aspects of a deal, including the SPA, due diligence and UK clearances, and works with the firm's Dhaka office on Bangladeshi company law, RJSC filings and Bangladesh Bank foreign exchange requirements. This lets a buyer or seller run a UK–Bangladesh transaction on a single coordinated timetable, with the same team tracking conditions in both jurisdictions.
Sources and official materials
- Companies Act 2006 — Share transfers, schemes of arrangement, squeeze-out
- The Takeover Panel — Takeover Code, Panel statements and consultations
- National Security and Investment Act 2021 — Mandatory notification and call-in powers
- Digital Markets, Competition and Consumers Act 2024 — Revised merger control thresholds
- Mergers: how to notify the CMA — CMA notification process
- Transfer of Undertakings (Protection of Employment) Regulations 2006 — Employee transfers on asset deals
- Tax when you buy shares — Stamp duty and SDRT on share purchases
General information only, current as at 21 October 2026. It is not legal advice and does not create a solicitor–client relationship. It reflects the law of England and Wales unless stated otherwise; Scotland and Northern Ireland have separate legal systems, and the law changes frequently. Check current official sources and take advice on the facts of your matter.