Legal advice for UK companies expanding into the US

The US is the obvious next market for many UK companies, and in 2025 it was the UK’s largest trading partner. The shared language makes it feel familiar, and that is where the risk lies. The US legal system works very differently from the UK’s, and the gap shows up in how you set up, who you can hire, how you are taxed and what your contracts say. Taking the right legal advice before expanding to the US is what keeps an ambitious move from becoming an expensive one.

Why the US is a different legal system, not just a new market

The first mistake is treating the US as a single market with one rulebook, it is a federal system layered over 50 states, each with its own rules on tax, employment, licensing and consumer protection. A company that is fully compliant in New York can be offside in California without changing a thing it does. The US is also a more litigious environment, and commercial disputes can be more aggressive and more expensive to resolve than UK companies expect. These UK vs US differences run deeper than spelling and tone, and they shape almost every decision that follows.

Getting your US structure right

Trading in the US through your existing UK entity can create a taxable presence there and expose the UK business directly to American liabilities and litigation, so it is rarely the right long-term structure. The usual route is to set up a US subsidiary owned by the UK parent, often incorporated in Delaware and structured as a C corporation. Delaware is a popular choice for its well developed corporate law and predictable courts, though a company with heavy operations in one state sometimes incorporates there instead. You will also need a registered agent in your state of incorporation and a US tax identification number to open a bank account and run payroll. From there, you register to do business in every state where you have employees or a real presence, and each registration brings its own filings and annual obligations.

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Employment law is the biggest shift

For most UK companies, hiring is where the differences bite hardest. US employment is generally at will, which means either side can usually end it at any time and with far fewer statutory protections than UK staff are used to. Pay, benefits, leave and notice rules vary from state to state, so a contract that works in Texas may fail in California, and US employees typically expect employer-provided health cover that UK staff do not, which adds to the real cost of each hire. The bigger trap is worker classification. Calling someone a contractor does not make them one if the day to day reality looks like employment, and getting it wrong can mean back taxes, penalties and unpaid benefit liabilities. This catches companies of every kind, from software firms hiring their first US salesperson to consultancies and recruitment businesses placing people on the ground.

Tax, data and ongoing US compliance

US compliance does not stop once you are set up. Federal and state taxes run side by side, and simply selling into a state can create a sales tax obligation there even with no office, through what is called economic nexus. Payroll adds another layer of state by state registration. Data protection is where UK vs US assumptions catch people out most often: the UK runs a single, GDPR based regime, while the US has no federal equivalent. Instead, the rules are a state by state patchwork, with around 20 states now operating their own comprehensive privacy laws and Indiana, Kentucky and Rhode Island the latest to take effect at the start of 2026. Sell to consumers in several states and you can fall under several of these regimes at once.

Contracts and intellectual property

US contracts are not UK contracts with the spelling changed, so reusing UK templates without adapting them is a real risk. Governing law and jurisdiction clauses need to reflect where you actually want a dispute heard. Liability and indemnity expectations differ, and US customers often expect to work from their own paper, which will be written for their protection rather than yours. Intellectual property assignment also needs handling to US standards, particularly where US employees or contractors are the ones creating it. These are the documents that decide who wins when something goes wrong, so they are worth getting right at the outset rather than in the middle of a dispute.

When to take UK and US legal advice

The hard part of expanding to the US is that these issues connect. Your entity choice affects your tax, your hiring affects your filings, and your contracts affect your exposure, so a decision that looks sensible on its own can create a problem somewhere else. That is why it helps to take legal advice from people who understand both systems rather than assembling it piece by piece from each side. At WTT, our legal team works across both UK and US law, drafting tailored US terms and helping UK companies set up correctly so they launch compliant rather than fixing problems later. If you are weighing up a move across the Atlantic, speak to our team.

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