US·UK Accountants

Insights · Cross-Border Planning

Moving to America With a Stocks and Shares ISA? Read This Before You Fly

US tax treats UK ISAs harshly — and the clean solutions mostly exist only before you become a US tax resident. What to do with your ISA before an American move, and why timing beats everything.

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By Sam H., Founder & Lead Advisor

ACCA · ACA · Reviewed by Sal T. · 2026-08-25

Of all the conversations we have with people moving from the UK to America, one produces more avoidable expense than any other — and it's about an account most movers consider the safest thing they own: the stocks and shares ISA.

Here's the uncomfortable truth: the IRS does not recognise your ISA. The wrapper that makes it tax-free in Britain is invisible to American law. And if your ISA holds what most ISAs hold — UK or Irish funds, index trackers, ETFs — then from the day you become a US tax resident, those holdings fall under one of the harshest regimes in the American tax code, with punitive rates and complex reporting for every fund, every year.

The window that closes on arrival

The reason this matters before you fly: sales made while you're still only a UK tax resident are, for ISA assets, typically tax-free — that's the ISA doing its job one last time. The same sale made after US residency begins lands inside the American net. So there is a window in which the problem can be dissolved at essentially no cost, and it closes on a date most people can't name precisely — because it isn't your flight date.

US residency runs on day-counting, and days spent stateside before the move — work trips, an early arrival on a business visa, house-hunting — can start your residency earlier than your visa suggests. We've seen movers who assumed an October start discover their residency began months earlier. Establishing your actual start date is step one; everything else is sequenced against it.

Not everything needs to go

Individual shares carry none of the fund problem — a portfolio of ordinary equities can often cross the Atlantic intact. Cash ISAs are merely inefficient, not toxic. The decisions are holding-by-holding, which is why the useful first document isn't your account value — it's the holdings list. And on the other side, the same exposure can usually be rebuilt within days using US-domiciled equivalents of the very funds you sold, often at lower fees.

The one-paragraph plan

Establish your true US residency start date. List the ISA's actual holdings. Sell what needs selling while the UK side is still free. Repurchase the clean equivalents after arrival. And put the whole sequence in writing before acting, because the moves are simple but the order is everything.

If your move is booked and your ISA is invested, this is genuinely time-critical work — and it's exactly what our pre-move planning covers.

Frequently asked questions

The ISA wrapper means nothing to the IRS — America taxes the account as if it were an ordinary investment account, and if it holds UK funds or ETFs, those typically fall under the punitive PFIC rules, with harsh tax treatment and complex annual reporting per fund. The UK tax benefits survive for UK purposes, but once you're a US tax resident they no longer protect you where you actually live.

For ISAs holding funds or ETFs, selling before US tax residency begins is very often the right move: UK gains inside an ISA are tax-free, so the sale usually costs nothing on the UK side, and it prevents the US fund rules attaching at all. Individual shares are different and can often be kept. The right answer depends on what the ISA actually holds — which is why the holdings list matters more than the account value.

Not necessarily the day your visa starts. US residency is determined by day-counting under the substantial presence test, and time spent in the US before your move — business trips, house-hunting, an early start on a B visa — can pull your residency start date earlier than you expect. The disposal window is measured against that date, not your flight date, so establishing it precisely is step one.

You can't add to an ISA once you're no longer UK resident, and keeping the account raises ongoing US reporting even where the holdings are clean. Many movers keep cash ISAs (which are merely inefficient, not toxic) and deal with investment ISAs before departure — but the account's future should be part of the pre-move plan rather than an afterthought.

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