International Tax Companies in London: Guide to Providers (2026)
AC
Acumon Chartered Accountants·13 min read
This practical guide reviews companies providing international tax services in London for businesses, international groups, entrepreneurs, and individuals with cross-border tax requirements. It is an overview rather than ranking companies against one another, with the focus on the scope and relevance of their international tax work. The selection includes larger companies with broad corporate, transfer pricing, mobility, and compliance capabilities, alongside more focused specialists in areas such as private client tax, inbound investment, and specific cross-border markets. Each profile gives context on the company’s client focus, international tax expertise, and areas of particular strength. The aim is to make the differences easier to compare and help readers identify a company suited to their structure, international footprint, and tax requirements.
Acumon
Acumon is a UK company of chartered accountants and registered auditors providing international tax services to businesses, corporate groups, entrepreneurs, and individuals with tax obligations across more than one jurisdiction.
The international tax team supports overseas businesses establishing operations in the UK, UK companies expanding internationally, and groups managing cross-border transactions between related entities. Its work covers the UK tax consequences of international structures as well as coordination with advisers in other jurisdictions where local input is required.
For inbound businesses, Acumon advises on questions such as whether to operate through a UK subsidiary or branch, permanent establishment exposure, tax registrations, VAT, employment obligations, and the ongoing UK compliance requirements of an overseas-owned entity. The company also works with UK subsidiaries of international groups and can coordinate reporting with overseas head offices.
International structures can create tax exposure through withholding taxes, double taxation, residence rules, financing arrangements, and transactions between related companies. Acumon supports treaty relief claims, foreign tax credit calculations, intercompany arrangement reviews, and documentation of cross-border transactions against the arm’s-length standard.
The international tax practice also covers individuals whose residence, employment, investments, or assets span different jurisdictions. Acumon advises on the UK statutory residence test, split-year treatment, foreign income and gains, arrival and departure planning, and double taxation issues affecting internationally mobile individuals.
Acumon works across international tax, corporate tax, VAT, payroll, accounting, audit, and advisory services, allowing cross-border tax matters to be considered alongside the UK reporting and operational requirements of an international group.
International Tax Capabilities
Acumon provides international tax support for both corporate and individual cross-border situations.
These include:
Inbound UK structuring for overseas companies
UK subsidiary and branch tax considerations
Permanent establishment analysis
Double taxation relief and treaty claims
Withholding tax reductions and reclaims
Foreign tax credit calculations
Statutory residence and split-year advice
Foreign income and gains considerations
Intercompany arrangement reviews and documentation
Cross-border VAT and employment tax matters
Coordination with overseas tax advisers
The scope can extend from initial UK market entry through to ongoing tax compliance and reviews of established international structures.
Regulatory Licences and Registrations
Acumon operates as a UK chartered accountancy practice and registered audit company. These registrations relate to its wider professional practice rather than international tax advice being a separately licensed service.
These include:
ICAEW Registered Audit Firm
UK Statutory Audit Registration
Acumon UK Limited registered in England and Wales
In-House Chartered Tax Adviser expertise
Former HMRC experience within the tax team
The wider regulatory and professional framework allows Acumon to combine international tax work with accounting, audit, compliance, and financial reporting support where these services form part of the same international group requirements.
Core Services
In addition to international tax advice, Acumon provides related services that support businesses and individuals with UK and cross-border financial obligations.
These include:
Corporate Tax planning and compliance
Private Client Tax
Tax Compliance and return preparation
VAT registration, reporting, and advisory
Payroll and employment tax
Statutory and group audit
Accounts and bookkeeping
Business advisory
Company secretarial support
Risk and governance services
International tax work can be coordinated with these services where a cross-border structure creates several connected UK requirements.
Acumon works with clients that are:
Establishing UK operations from overseas
Creating a UK subsidiary or branch
Expanding an existing UK business internationally
Receiving dividends, interest, or royalties across borders
Managing transactions between related companies in different countries
Reviewing permanent establishment exposure
Claiming relief from double taxation
Employing internationally mobile personnel
Arriving in or leaving the UK
Coordinating UK tax reporting with an overseas parent or adviser
Reviewing the international tax position alongside the underlying structure allows Acumon to address UK compliance, treaty treatment, cross-border payments, and related reporting requirements within the same engagement.
Address: 1-2 Craven Road, Ealing, London, W5 2UA, UK
Grant Thornton UK
Grant Thornton has a dedicated international tax practice covering UK businesses expanding overseas as well as international groups operating or investing in the UK. The service includes international structuring, overseas expansion, transfer pricing, Pillar Two, global mobility, international indirect tax and global compliance reporting.
Its London office supports tax, audit and advisory work for businesses ranging from smaller companies to multinational organisations. The international tax practice is particularly relevant where a company wants UK advice connected with a wider multi-jurisdictional project and needs coordination through the Grant Thornton international network.
Key Facts
Ideal for: Growing and established companies with multi-country tax requirements
Core services: International structuring, transfer pricing, Pillar Two, global mobility, international indirect tax
International focus: Inbound and outbound corporate tax
Location: 8 Finsbury Circus, London
Additional capability: Global compliance and reporting coordination
RSM provides international corporate tax services for companies entering the UK, expanding from the UK and managing established multi-country operations. Its work includes entity and branch considerations, tax registrations, transfer pricing, international corporate structuring and coordination of global compliance obligations. The London tax team includes advisers working with both multinational and owner-managed companies. RSM also has separate international mobility and private client expertise, making the practice relevant where international business operations intersect with employee or shareholder taxation.
Key Facts
Ideal for: Mid-market and larger companies operating internationally
Core services: International corporate tax, structuring, compliance and transfer pricing
Expansion support: UK inbound and UK outbound projects
Additional services: Global mobility and international private client tax
Location: London
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
BDO
BDO’s London tax practice works with international groups, listed companies, mid-market businesses and private clients. Its international tax capability includes cross-border structuring, financing, mergers and acquisitions, profit repatriation, intellectual property arrangements and transfer pricing.
The London office is located on Baker Street and works with multinational businesses through BDO’s international network. This gives the firm a broad corporate focus while maintaining a substantial mid-market client base.
Key Facts
Ideal for: Mid-market groups and larger international companies
Core services: Corporate international tax and transfer pricing
Specialization: Cross-border structuring, financing and profit repatriation
Transaction support: International mergers, acquisitions and disposals
Location: 55 Baker Street, London
Contact Information
Website: www.bdo.co.uk
Phone: 020 7486 5888
Address: 55 Baker Street London, W1U 7EU, United Kingdom
LinkedIn: www.linkedin.com/company/bdo-llp
Instagram: www.instagram.com/bdo_uk
KPMG UK
KPMG’s international and complex corporation tax practice advises businesses investing across borders and companies managing established international structures. Areas covered include international structuring, cross-border financing, intellectual property, global supply chains, transfer pricing and international tax risk.
Its wider international tax capabilities include Pillar Two and transfer pricing work for multinational groups. KPMG’s UK headquarters are in Canary Wharf, with a substantial London tax practice serving private businesses, listed companies and global enterprises.
Key Facts
Ideal for: Multinational groups and companies with complex international structures
Core services: International corporate tax, structuring and transfer pricing
Specialization: Financing, intellectual property, cross-border reorganisations and tax risk
Deloitte provides international tax advisory and compliance services for multinational organisations. Its international tax offering covers areas such as international tax compliance, Pillar Two, financing and treasury taxation, supply chains, intellectual property, legal entity structuring, foreign tax credits and cross-border M&A.
Transfer pricing, tax technology, M&A tax and international tax controversy can be brought into wider engagements where required. Deloitte has a major London Tax and Legal practice operating from its New Street Square offices.
Key Facts
Ideal for: Large international and multinational organisations
Core services: International tax advisory and compliance
International areas: Pillar Two, foreign tax credits, financing and structuring
Transaction services: International M&A tax
Location: New Street Square, London
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
Instagram: www.instagram.com/deloitte_uk
EY UK
EY combines corporate international tax capabilities with specialist cross-border services for private businesses, entrepreneurs and internationally mobile individuals. Its UK tax practice covers business tax, international tax, transaction tax, compliance and reporting, alongside international private client work.
A particularly distinct part of the practice is its US/UK Cross Border Tax Services team, which advises individuals, business owners, trusts and families dealing with both tax systems. EY operates major London offices at London Bridge and Canary Wharf.
Key Facts
Ideal for: Multinationals, private businesses and internationally connected private clients
Core services: International corporate tax, transaction tax and compliance
Cross-border specialty: US/UK personal and business owner taxation
Private client capability: International wealth and tax planning
Location: London Bridge and Canary Wharf, London
Contact Information
Website: www.ey.com
Phone: +44 20 7951 2000
Address: 1 More London Place, London SE1 2AF
LinkedIn: www.linkedin.com/company/ernstandyoung
Facebook: www.facebook.com/EY
Twitter: x.com/EYnews
Forvis Mazars
Forvis Mazars provides global tax services for businesses operating across jurisdictions, including large multinationals, mid-market companies and companies making their first international expansion. Its corporate international tax work covers global compliance, cross-border structuring, transfer pricing, Pillar Two, international transactions and mobility.
The practice also has a separate international private client tax service covering tax planning, residence, expatriate matters, overseas assets, trusts and double taxation issues. Its London office provides international tax, transfer pricing and expatriate tax services alongside broader corporate and personal tax work.
Key Facts
Ideal for: International companies and private clients with multi-jurisdictional affairs
Core services: Global tax, compliance, structuring and transfer pricing
Corporate focus: International expansion and cross-border transactions
Private client focus: International residence, assets and wealth structures
Location: London
Contact Information
Website: www.forvismazars.com
Phone: +44 (0) 20 7063 4000
Address: 30 Old Bailey, London, EC4M 7AU, United Kingdom
Moore Kingston Smith has a dedicated international tax practice for businesses operating across multiple jurisdictions. Its services include cross-border tax planning, corporate structuring, transfer pricing, Pillar Two and BEPS matters, CFC rules, country-by-country reporting, permanent establishment risk and international indirect tax.
The firm also provides cross-border private client advice and maintains a specialist US-UK tax team. Through Moore Global, it can coordinate tax and compliance work with advisers outside the UK. Its City office is on Appold Street in London.
Key Facts
Ideal for: Owner-managed, growing and established international businesses
Core services: International corporate tax, structuring and transfer pricing
Compliance areas: Pillar Two, CFC rules, CbCR and PE risk
Additional specialty: US-UK and private client cross-border tax
PKF Littlejohn provides international tax services from London for multinational listed groups, privately owned companies and businesses establishing new operations overseas. The practice advises on foreign tax obligations, permanent establishments, international business structures, transfer pricing and profit repatriation.
The firm’s broader tax practice covers both corporate and private client international matters. Through the PKF network, it can coordinate projects involving tax requirements in multiple countries rather than limiting the engagement to the UK component.
Key Facts
Ideal for: Privately owned businesses, international groups and listed companies
Core services: International tax planning and compliance
Specialization: Permanent establishments, cross-border structuring and repatriation
Gerald Edelman has a London-based international tax team advising both individuals and businesses moving into or out of the UK. Its cross-border services cover international tax planning, residence questions, double taxation agreements and tax considerations surrounding overseas investments and expansion.
Its international work can be combined with corporate tax, VAT, M&A and other accounting services where an overseas business is establishing UK operations. This gives the practice a broad remit across both company and owner-level international taxation.
Key Facts
Ideal for: International businesses, entrepreneurs and internationally mobile individuals
Core services: Cross-border and international tax advice
Private client areas: Residence, foreign assets and double taxation
Business areas: UK inbound investment and overseas growth
Kreston Reeves provides international tax services from its London and South East offices for corporates, entrepreneurial companies and internationally mobile private clients. The practice works on both business and personal international taxation and coordinates overseas requirements through the Kreston network.
Published examples of its international tax work include supporting overseas businesses entering the UK and European markets, UK technology companies expanding into the Middle East and overseas investors structuring UK interests. Transfer pricing forms part of the wider international tax offering.
Key Facts
Ideal for: Mid-market companies, growth businesses and international private clients
Core services: International corporate and personal tax
Expansion support: UK inbound and overseas expansion
Related service: Transfer pricing
Location: Shoreditch, London
Contact Information
Website: www.krestonreeves.com
Phone: +44 (0)330 124 1399
Address: 2nd Floor, 168 Shoreditch High Street, London, E1 6RA
LinkedIn: www.linkedin.com/company/kreston-reeves
Twitter: x.com/KrestonReeves
UHY Hacker Young
UHY Hacker Young’s London office provides UK and international tax planning for companies, individuals and trusts. It also supports overseas companies establishing operations in the UK, making the practice relevant to both inbound investment and existing cross-border structures.
International tax work can be combined with VAT and customs advice, corporate finance, tax investigations and wider accounting services. International assignments are supported through the wider UHY network where local advice outside the UK is required.
Key Facts
Ideal for: Owner-managed companies, international businesses and private clients
Core services: UK and international tax planning
Client types: Companies, individuals and trusts
Inbound support: Overseas companies establishing in the UK
Buzzacott has a particularly strong cross-border focus on tax matters involving the United States and United Kingdom. Its US/UK tax practice advises individuals, entrepreneurs and trusts on tax compliance and planning where obligations arise under both systems.
Services cover tax returns as well as planning involving trusts, businesses, pensions and expatriation. Unlike some providers in this guide, the international tax proposition is therefore more specialised geographically rather than centred on broad multinational corporate tax across many jurisdictions. Buzzacott operates from a single London office near St Paul’s.
Key Facts
Ideal for: US-connected individuals, entrepreneurs and trusts
Core services: US-UK tax compliance and planning
Specialization: Cross-border personal and private client taxation
Blick Rothenberg provides international tax advice coordinated from London. Its team advises multinational organisations on international tax strategy and cross-border transactions, drawing on overseas accounting and advisory companies through the Allinial Global association.
The international tax service covers corporate reorganisations, cross-border M&A, international expansion, withholding taxes, tax-efficient financing, intellectual property, transfer pricing and global mobility. It also maintains specialist US-UK private client capabilities, making the firm relevant to internationally connected owners as well as corporate groups.
Key Facts
Ideal for: International businesses, overseas investors and internationally connected private clients
Core services: International tax strategy and cross-border transactions
Corporate areas: Reorganisations, M&A, financing and withholding tax
Related services: Transfer pricing, global mobility and US-UK tax
Location: London
Contact Information
Website: www.blickrothenberg.com
Phone: +44 (0)20 7486 0111
Address: 16 Great Queen Street, Covent Garden, London, WC2B 5AH
The choice of an international tax company in London depends on business size, sector, the maturity of internal tax processes, international exposure, and relevant regulatory requirements. Some companies combine corporate tax, transfer pricing, mobility, compliance, and private client support within an integrated international service, while others concentrate on narrower cross-border tax areas. The jurisdictions involved and the complexity of ownership, transactions, employees, and reporting obligations can also influence which type of expertise is appropriate. A suitable partner should provide clear independent tax assurance alongside practical measures that help reduce exposure to tax risks and support long-term resilience. This guide is intended to provide neutral context for comparing different companies and identifying an approach that fits the organisation’s particular international tax needs.
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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