Tax Due Diligence Companies in London: A Practical Selection Guide (2026)
AC
Acumon Chartered Accountants·9 min read
Tax due diligence services in London cover a wide range of needs, from M&A transactions and investment reviews to assessing potential tax risks before important business decisions. This practical guide provides an overview of companies in this area rather than ranking them, focusing on their expertise, client types, and areas of support. The companies included vary from larger organisations with broad advisory capabilities to more specialised tax specialists focused on specific transaction requirements. The aim is to give readers useful context about each company and help them identify options that match their own circumstances.
Acumon
Acumon is a UK firm of chartered accountants and registered auditors providing tax due diligence services to businesses, investors, and corporate groups involved in transactions. The firm supports organisations with the review of tax positions, potential exposures, and compliance matters connected with acquisitions, disposals, and restructuring activities.
The firm works with owner-managed businesses, private companies, and international groups requiring detailed analysis of tax matters during important business decisions. Tax due diligence engagements are supported by a structured approach that combines accounting knowledge, tax expertise, and an understanding of transaction-related requirements.
Acumon provides tax due diligence support as part of its wider advisory services, helping clients assess historical tax positions, identify potential liabilities, and understand issues that may affect transaction planning. The firm’s experience with financial reporting and audit requirements provides additional context when reviewing tax information and supporting documentation.
Tax due diligence often involves reviewing corporate structures, previous tax filings, available reliefs, and areas where additional clarification may be required before completing a transaction. Acumon works with management teams, investors, and advisers to provide an independent assessment of relevant tax considerations.
The firm supports businesses operating in different sectors, including organisations with UK operations and international structures. Experience with financial reporting, statutory requirements, and group structures allows Acumon to assist clients with tax reviews connected with a variety of transaction scenarios.
Acumon works with clients throughout the transaction process by providing clear analysis of tax matters and helping management teams understand potential risks, opportunities, and areas requiring further attention.
Tax Due Diligence Capabilities
Acumon provides tax due diligence services for a range of transaction and business situations.
These include:
Mergers and acquisitions involving UK businesses
Vendor and buy-side tax due diligence reviews
Corporate group tax assessments
Review of historical tax positions and exposures
Analysis of tax compliance and reporting matters
Tax reviews for international business structures
Tax due diligence engagements are typically supported by experienced accounting and tax professionals who assess relevant documentation and provide findings tailored to the transaction context.
Regulatory Licences and Registrations
Acumon operates as a regulated UK accountancy and audit firm with professional registrations that support its advisory and financial services work.
These include:
UK statutory audit registration
Public Interest Entity (PIE) audit licence
Jersey audit licence
Isle of Man audit licence
Cayman Islands audit licence
British Virgin Islands audit licence
These registrations support Acumon’s ability to work with organisations that operate across different jurisdictions and require professional support with financial and regulatory matters.
Core Services
In addition to tax due diligence, Acumon provides a range of accounting, audit, and advisory services that support businesses throughout different stages of development.
These include:
Tax due diligence reviews
Transaction advisory support
Financial due diligence
Statutory external audit
Group and subsidiary audits
Internal audit and governance reviews
Risk management and compliance support
Acumon’s tax due diligence services are used in situations where businesses need a clearer understanding of tax matters before completing transactions, restructuring operations, or preparing for investment.
The firm supports organisations that are:
Reviewing a potential acquisition or disposal
Preparing for investment or ownership changes
Managing complex corporate structures
Expanding into international markets
Early involvement in a transaction process can help ensure that relevant tax information is reviewed properly and that potential issues are identified before decisions are finalised.
Address: 1-2 Craven Road, Ealing, London, W5 2UA, UK
BDO
BDO provides tax advisory and transaction support services for businesses, investors, and corporate groups involved in acquisitions, disposals, and restructuring activities. Its tax teams advise on transaction tax matters, tax risk management, and due diligence reviews, helping clients assess potential issues before completing deals. The firm supports organisations by analysing historical tax positions, possible liabilities, compliance matters, and other factors that may affect transaction structures. BDO works with clients across different sectors, providing tax expertise alongside broader advisory services.
Key Facts
Ideal for: Mid-sized and larger organisations requiring transaction tax support
Core services: Transaction tax, tax advisory, due diligence support
Specialization: Corporate transactions and tax risk assessment
Address: 55 Baker Street London, W1U 7EU, United Kingdom
LinkedIn: www.linkedin.com/company/bdo-llp
Instagram: www.instagram.com/bdo_uk
Grant Thornton
Grant Thornton provides tax advisory and transaction services for organisations involved in acquisitions, investments, and business restructuring. Its tax teams support due diligence processes by analysing tax positions and identifying matters that may require attention before completion.
The firm works with businesses across different sectors and provides broader advisory support alongside tax reviews, including transaction-related services.
Key Facts
Ideal for: Companies requiring tax advice during complex transactions
Core services: Transaction tax, tax advisory, due diligence support
Specialization: Corporate transactions and restructuring
Location: London, UK
Industries: Financial services, technology, manufacturing, and other sectors
PwC provides tax due diligence and transaction tax services for businesses, private equity investors, and corporate groups. Its teams advise on tax considerations connected with mergers, acquisitions, disposals, and investment decisions.
PwC’s tax specialists work alongside other transaction advisers to review tax risks, structures, and compliance matters that may influence negotiations or deal outcomes.
Key Facts
Ideal for: Large businesses, investors, and multinational groups
Core services: Tax due diligence, transaction tax, deal advisory
Specialization: Complex corporate transactions
Location: London and UK-wide
Industries: Multiple sectors including financial services and technology
Address: 1 Embankment Place London WC2N 6RH United Kingdom
LinkedIn: www.linkedin.com/company/pwc-uk
Facebook: www.facebook.com/PwCUK
Instagram: www.instagram.com/pwc_uk
Deloitte
Deloitte provides transaction tax and advisory services for businesses involved in acquisitions, disposals, and restructuring projects. Its tax professionals support due diligence assignments by reviewing tax positions and identifying potential risks.
The firm works with organisations ranging from private companies to international groups requiring support with complex transaction matters.
Key Facts
Ideal for: Organisations involved in large-scale transactions
Core services: Transaction tax, tax advisory, M&A support
Specialization: Complex tax reviews and corporate transactions
Location: London and UK-wide
Industries: Financial services, consumer, technology, and industrial sectors
Contact Information
Website: www.deloitte.com
Phone: +44 (0)20 7936 3000
Address: 1 New Street Square London, EC4A 3HQ United Kingdom
LinkedIn: www.linkedin.com/company/deloitte
Facebook: www.facebook.com/deloitteuk
Twitter: x.com/deloitteuk
KPMG
KPMG provides tax advisory and transaction support services for companies, investors, and corporate groups involved in acquisitions, disposals, and investments. Its tax teams support due diligence work by reviewing tax exposures, compliance matters, historical tax positions, and issues connected with proposed transaction structures. The company advises both buyers and sellers at different stages of corporate transactions, including the assessment of potential tax risks before completion. KPMG UK also provides broader transaction tax and structuring support for organisations dealing with complex domestic and cross-border transactions.
Key Facts
Ideal for: Corporate groups, investors, and transaction teams
Core services: Tax due diligence, transaction advisory, tax structuring
Specialization: M&A tax support
Location: London and UK-wide
Industries: Financial services, infrastructure, technology, and other sectors
Evelyn Partners provides tax advisory services and transaction support for businesses, entrepreneurs, and private clients. Its teams assist with tax planning, corporate transactions, ownership changes, and financial matters that require specialist tax guidance. The company works with owner-managed businesses, family businesses, and corporate clients seeking support with tax considerations during important decisions. Its advisory services cover a range of business situations, including restructuring, growth planning, and changes in ownership structures. Evelyn Partners combines tax expertise with wider financial advisory support to help clients address tax matters connected with their long-term objectives.
Key Facts
Ideal for: Owner-managed businesses and private clients
Core services: Tax advisory, transaction support, business planning
Specialization: Tax matters for privately owned businesses
Location: London and UK-wide
Client types: Entrepreneurs, private companies, family businesses
Address: 45 Gresham Street, London, EC2V 7BG, United Kingdom
LinkedIn: www.linkedin.com/company/evelynpartners
Facebook: www.facebook.com/evelynpartners
Twitter: x.com/evelynpartners
Instagram: www.instagram.com/evelynpartners
RSM
RSM provides tax advisory and transaction services for businesses operating in the UK and internationally. Its tax teams support due diligence assignments by reviewing tax positions, risks, and opportunities connected with corporate transactions.
RSM works with middle-market businesses and organisations requiring specialist advice across accounting, audit, tax, and consulting areas.
Key Facts
Ideal for: Middle-market businesses involved in transactions
Core services: Tax advisory, transaction support, due diligence
Specialization: Business tax and corporate transactions
Location: London and UK-wide
Client types: Private companies and international groups
Contact Information
Website: www.rsmuk.com
Phone: +44 (0)20 3201 8000
Address: 25 Farringdon Street London EC4A 4AB
LinkedIn: www.linkedin.com/company/rsm-uk
Instagram: www.instagram.com/rsm.uk
Haysmacintyre
Haysmacintyre provides tax advisory and transaction support services for businesses, entrepreneurs, and investors. The firm advises clients on tax matters connected with acquisitions, disposals, restructuring, and business growth.
Its tax teams support due diligence processes by reviewing potential liabilities, tax positions, and compliance considerations. The firm works particularly with owner-managed businesses, private equity-backed companies, and organisations requiring specialist tax advice.
Key Facts
Ideal for: Owner-managed businesses, investors, and growing companies
Core services: Tax advisory, transaction support, corporate tax, due diligence
Specialization: Tax advice for privately owned and entrepreneurial businesses
Crowe provides tax advisory, audit, and consulting services for businesses requiring support with financial transactions and tax planning. Its advisers assist organisations with tax reviews, restructuring, and transaction-related matters.
The firm works with businesses of different sizes and provides support across corporate tax, international tax, and advisory services where tax risks need to be assessed.
Key Facts
Ideal for: Businesses requiring tax advisory support during transactions
Forvis Mazars provides audit, tax, and advisory services to businesses, investors, and international groups involved in various financial activities. Its transaction tax specialists support organisations with acquisitions, disposals, and restructuring projects by reviewing tax considerations and potential risks. The company assists clients with assessing tax implications before transactions are completed, including analysis of tax exposures, compliance matters, and transaction structures. Its advisory teams work with organisations that require support with complex tax decisions connected to corporate changes and investment activities.
Key Facts
Ideal for: Mid-market companies and international businesses
Core services: Transaction tax, tax advisory, due diligence support
Specialization: Corporate transactions and cross-border tax matters
This guide highlights a selection of tax due diligence services in London rather than ranking providers. The firms included differ in transaction focus, client types, and the scale of advisory support they provide.
Businesses comparing options can consider factors such as transaction complexity, required tax expertise, industry experience, and the level of wider financial support needed alongside due diligence.
AC
Written by the Acumon team
Acumon is an ICAEW-registered firm of chartered accountants and registered auditors
based in London, with offices in Pitstone, Aylesbury and Bournemouth. Need advice on
anything covered here? Talk to us.
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