If you are an American living in the UK and you have tried to invest, you have probably run into a wall. A UK platform greys out the US funds you actually want. A US broker sends a letter saying it can no longer hold your account now that you live abroad. You open a stocks and shares ISA and find that the sensible index funds are somehow off limits. It can feel as though the system is designed to stop you doing the one responsible thing you are trying to do, which is to invest for your future.

You are not imagining it, and you are not doing anything wrong. You have walked into the gap between two tax systems that were never built to work together. This guide explains, in plain English, why the walls are there and how to invest properly around them.

Who This Guide Is For

This guide is for US persons living in the UK. That means US citizens, including so-called accidental Americans who may never have lived in the States, and green card holders, including those whose cards have lapsed but who have not formally given up the status. If that is you, the US expects you to file, and potentially pay tax on, your worldwide income for life, wherever you live. That single fact is the root of almost everything that follows.

Here is the good news. Most of the difficulty is structural, not personal. Once you understand the handful of rules causing the walls, the path through becomes surprisingly clear. There is even a part of the system that works strongly in your favour, and we will get to it. But first, the two hidden causes.

The nuance almost everyone misses: this is a distribution barrier, not an eligibility rule

There is no rule saying a US listed ETF cannot sit inside a UK wrapper. ISA eligibility turns on whether an investment is a security listed on a recognised stock exchange, which a US listed ETF is, and nothing in the ISA rules requires a fund to be a UCITS or a UK authorised fund. HMRC reporting fund status is a separate question. It does not decide ISA eligibility, it decides how the same ETF is taxed in the UK when you hold it outside a wrapper, which is why it matters so much in a General Investment Account. What stops you buying one on a retail platform is the missing disclosure document and the platform policy built on top of it, not the wrapper.

That distinction matters, because a barrier created by how a product is distributed can be dealt with at the point of advice. Where the advice is given by an adviser holding individual SEC authorisation, qualifying US listed ETFs can be bought and held for a UK resident US person inside an ISA and a General Investment Account, as well as inside a SIPP. The pension is still the best wrapper, for the reasons below, but it is no longer the only place you can invest properly.

You will also see the counter-argument that a US listed ETF is off limits because it is not a recognised scheme under the Overseas Funds Regime. Recognition under that regime governs whether a fund can be promoted to UK retail investors at large. It is a marketing and distribution permission, not a rule about what an ISA or a General Investment Account is allowed to hold, and it does not prevent a suitably authorised adviser transacting in a US listed ETF for a client who has taken advice. The question is not whether the fund sits on a UK approved list for mass-market promotion. It is whether the person advising you holds the permissions to advise on it.

The US-UK Tax Treaty, in Plain English

The treaty is the rulebook that stops the two systems double-charging you. You do not need to read it, but three things are worth knowing.

It protects you from genuine double taxation. In almost no situation will you pay full tax to both countries on the same income. As a rough rule, you pay the higher of the two rates, split between the two governments, rather than both rates stacked on top of each other.

It protects pensions. As above, this is the most valuable feature of the treaty for most people.

It does not recognise everything. Some accounts that are tax free in one country are fully taxable in the other. The big ones to remember: a UK ISA is tax free for the UK but fully taxable by the US, and a US 529 college plan or HSA is tax advantaged for the US but fully taxable by the UK. Neither country gives you credit for the other tax break.

Your Accounts, in Order of Priority

Here is how the main accounts stack up for a US person in the UK. Individual circumstances vary, but this is the typical order of preference.

UK workplace pension (usually first)

If you are employed, your workplace pension is almost always the place to start. Your employer must enrol you and must contribute at least 3%, which is free money. It is tax-deferred in both countries and has no PFIC issues. The trade-off is access: you cannot touch it until age 55, rising to 57 from April 2028. One nuance for US filers: if you personally contribute more than your employer does, some advisers take the view that the pension becomes a reportable foreign trust for the IRS. More on that below.

Roth IRA (excellent, with one condition)

Both countries recognise a Roth IRA, and growth and qualifying withdrawals are tax free. There is no PFIC issue. The one condition is that you must have US earned income to contribute, and you cannot manufacture that by excluding your salary under the Foreign Earned Income Exclusion. In practice this usually means using the Foreign Tax Credit instead. It is also far easier to open a Roth before you leave the US. If you are weighing whether to convert an old pension pot into a Roth, see our guide on 401(k) to Roth IRA conversion tax for UK residents, which explains what the online adverts get wrong.

UK SIPP (strong, especially for consolidating)

A SIPP is a personal pension you control, very similar to a workplace pension but without an employer. Same treaty protection, same absence of PFIC issues. It is the natural home for consolidating old or scattered pensions, and often gives you better and cheaper investment options. The foreign trust reporting question below is a little sharper for a SIPP, because there are usually no employer contributions.

Stocks and shares ISA (the famous trap, and the way round it)

This is where Americans get caught. An ISA is tax free for the UK and looks a little like a Roth, but the US does not recognise it, so the wrapper itself gives you no PFIC protection. An ISA quietly filled with UK index funds is one of the most expensive mistakes an American in Britain can make, and it is common. What that does not mean is that you are stuck picking individual shares. Because qualifying US listed ETFs are not PFICs and are eligible ISA investments, they can be held inside an ISA where the advice comes from an adviser holding individual SEC authorisation, so a properly diversified ISA portfolio is available to you. Two points still hold. The ISA gives you no US tax shelter, so the dividends and gains inside it stay reportable and taxable in the US every year even though the UK ignores them, and that asymmetry is worth modelling before you fund one. And an ISA usually still sits behind your pension allowance in the queue, so it rarely makes sense to fund one ahead of a pension, if you can use a Roth instead, or if you plan to move back to the US soon.

Lifetime ISA (niche)

A Lifetime ISA adds a 25% government bonus, but locks the money away until you buy a first home or reach 60, and the bonus is taxable by the US. The US treats it in the same way as a normal ISA, and because the provider choice for a Lifetime ISA is far narrower, the US listed ETF route is rarely available inside one in practice. Niche, but occasionally useful.

General Investment Account (no shelter, but workable)

A General Investment Account has no contribution limit and no tax shelter, so both countries tax it as you go. To use one well you need holdings that are non-PFIC for US purposes and HMRC reporting funds for UK purposes, so that your gains are taxed as capital gains rather than at income rates. Qualifying US listed ETFs meet both tests at once, and they can be held in a GIA where the advice comes from an adviser holding individual SEC authorisation. That makes a GIA a perfectly workable place to invest rather than the dead end it is often described as. It simply comes after the pensions and, where appropriate, the ISA.

US employer plans and old 401(k)s

The treaty respects US workplace plans well. You usually cannot keep contributing once you live in the UK, but you can generally leave them where they are, or roll them into an IRA to consolidate and cut fees, provided your broker will keep serving you abroad. There are no PFIC issues inside these accounts. Withdrawals are where it gets technical: broadly, a lump sum tends to be taxed by the US but not the UK, while regular payments can be taxed by both with credits to prevent true double tax. Our guide to 401(k) to IRA rollovers for Americans living in the UK walks through the mechanics.

HSAs and 529 plans (usually not worth it)

Both are US tax breaks that the UK simply ignores and taxes as ordinary investment accounts, often at higher income rates because they rarely hold HMRC reporting funds. You also usually cannot keep funding an HSA once you are in the UK. In many cases these are best dealt with before you move, with advice.

So How Do You Actually Buy US ETFs?

This is the question that brings most people here. The short version: the US ETFs you want are not PFICs, and many are HMRC reporting funds, so they are tax-friendly on both sides. The only real obstacle is access, and access is a distribution question rather than a legal one. The main routes are:

• Holding them inside a US IRA or rolled-over 401(k).
• Holding HMRC reporting US listed ETFs inside a SIPP that allows them.
• Holding qualifying US listed ETFs inside an ISA or a General Investment Account, where the advice comes from an adviser holding individual SEC authorisation.
• Qualifying as an elective professional client, which a few platforms will consider but very few apply consistently.

The important point is that the wrapper is not the obstacle. The route that opens up an ISA and a General Investment Account, rather than only a pension, is advice from an adviser authorised on both sides of the Atlantic. An adviser without SEC authorisation cannot advise a US person on funds at all, which is why that route leaves you with individual stocks and bonds. We go through each option, and the tactics we do not recommend, in our guide on how to invest in US listed ETFs from the UK.

A Word on IRS Form 3520 and Foreign Trusts

You may come across alarming talk that your UK pension or SIPP must be reported to the IRS as a foreign grantor trust on Forms 3520 and 3520-A, with heavy penalties for getting it wrong. This is a genuinely unsettled area with several respectable views, and it does not change the PFIC position. It is exactly the kind of judgement call where coordinated US and UK advice earns its keep.

Doing This Without the Headache

The reason this is so hard to do alone is that no single adviser usually sees both halves. A UK adviser may not understand PFIC or US filing. A US adviser may not understand ISAs, SIPPs or HMRC reporting funds. The whole point of coordinated cross-border advice is to make the two systems work together rather than against each other.

What This Means for You

If you are a US person in the UK, the walls you have been hitting are real, but they are also navigable once you build in the right order. For most people that order is simple: fill the pension wrappers first, because that is where your money can grow without the PFIC penalty, then decide where an ISA and a General Investment Account fit after that, built with qualifying US listed ETFs rather than UK funds. The account that looks most attractive at first glance, an ISA full of UK index funds, is the one that creates the biggest US tax problem. The same wrapper holding US listed ETFs can be entirely sensible.

Your own answer will depend on your employment, your existing US and UK accounts, whether you expect to return to the States, and how your provider treats US-connected clients. None of that is one-size-fits-all, which is why a coordinated plan matters more here than almost anywhere else in personal finance. If you are unsure where to start, start with the wrappers you already have and work out which ones are working for you and which ones are quietly working against you.

About Cameron James and How We Are Regulated

Cameron James is a financial planning firm authorised and regulated in the United Kingdom by the Financial Conduct Authority (FCA). Cameron James advisers are SEC authorised in the US, and hold individual EU/EEA authorisations where applicable. That authorisation on both sides of the Atlantic is what allows us to advise on your US accounts and your UK accounts within a single coordinated plan, rather than leaving you to stitch together UK-only and US-only advice that does not join up. It is also what allows us to use US listed ETFs for you inside an ISA and a General Investment Account, not only inside a pension.

In practice, that means we can:

• Build your plan around the PFIC-safe pension wrappers first, where your money can actually grow without penalty.
• Use US listed, non-PFIC, HMRC reporting ETFs where appropriate, inside a SIPP, an ISA or a General Investment Account rather than only inside a pension.
• Handle the provider and account-opening problems that stop most people before they start.
• Keep your US and UK tax reporting aligned, so nothing falls down the gap between the two systems.