American Business Guide

A guide for American companies setting up a business and American citizens working in the UK. HW Fisher advises many American companies and American citizens who have taken up employment here. We would be happy to speak to you if you would like to learn more.

While you’re focused on growing your business, trust us to take care of the UK tax and compliance detail behind the scenes. The guide is a practical walkthrough of the rules affecting American companies setting up in the UK and US citizens working here. It’s designed for anyone navigating a US-UK move, from founders opening their first UK office to individuals relocating for work, and it explains:

• The difference between operating as a UK branch and setting up a UK subsidiary
• How Permanent Establishment (PE) status is determined and what triggers UK tax liability
• Corporation tax rates, payment deadlines and instalment thresholds
• Tax incentives available for innovative businesses, including R&D relief and the Patent Box
• VAT registration rules for US businesses selling goods and services into the UK
• UK tax residence rules and how they affect American citizens working here
• The Foreign Income and Gains (FIG) regime for new UK residents
• Deductions and exemptions available to foreign nationals, including Overseas Workday Relief and Detached Duty Relief

Should a US company set up a branch or a subsidiary in the UK?

It depends on the business’s priorities. A branch (technically a Permanent Establishment) is simpler to close down but requires the parent company’s financial statements to be filed publicly in the UK, which many privately owned US corporations prefer to avoid. A subsidiary keeps the US parent’s accounts private and is liable to UK tax only on its own profits but involves separate incorporation and filing obligations. The guide explains the tax treatment of both routes, including how losses, profit repatriation and cross-border loan funding are handled.

Does a US company need to register for VAT in the UK?

It depends on how goods and services are supplied. Most B2B services supplied from the US don’t require UK VAT registration, but US businesses selling goods within the UK, or providing digital services to UK consumers, generally do. The guide sets out the different registration formats available, including appointing a UK VAT agent or representative, and explains how US businesses can reclaim VAT incurred on UK business trips.

How is UK tax residence determined for US citizens working here?

Residence is based primarily on the number of days spent in the UK each tax year, combined with other factors such as accommodation, family ties and employment. Individuals in the UK for fewer than 16 days are generally not resident, while those here for more than 183 days always are. The guide explains how residence status is assessed between these extremes, and how the UK’s double tax treaty with the US affects individuals who may be considered resident in both countries.

What tax relief is available to Americans newly arrived in the UK?

New UK residents who haven’t been UK tax resident in the last 10 years may qualify for the Foreign Income and Gains (FIG) regime, which can shelter certain foreign income and gains from UK tax for up to 4 tax years. Other reliefs covered in the guide include Overseas Workday Relief for earnings linked to work performed outside the UK, and Detached Duty Relief for employees seconded to the UK for under two years.

Download the full US to UK Business Guide or get in touch with our international tax experts today.

Published: January 30, 2026

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