You Can Keep Your ISA When You Move Abroad, But There's a Catch

Most agency founders I speak with assume that once they leave the UK, their ISA gets frozen or shut down. That is not correct.

You can keep your existing Stocks and Shares ISA open. The tax wrapper remains intact. You do not pay UK tax on the growth or dividends inside it, even while you are resident overseas. You just cannot make new contributions once you are non-resident. The annual £20,000 allowance stops the moment you leave.

But there is a specific trap that catches founders who try to reorganise their portfolio before or after moving. It is called the "bed and breakfast" rule. And it applies to ISAs in a way most people do not expect.

This post explains exactly how the rule works, why it matters for agency founders moving to Dubai or elsewhere, and how to avoid triggering an unexpected tax bill.

What Is the "Bed and Breakfast" Rule?

The bed and breakfast rule is an anti-avoidance measure from HMRC. It stops you from selling shares one day and buying them back the next just to realise a capital gain or loss for tax purposes.

Under normal circumstances, if you sell shares and then repurchase the same shares within 30 days, HMRC treats the sale as if it never happened for capital gains tax purposes. The original cost base carries forward. You do not crystallise a gain or loss.

The rule is codified in Section 106A TCGA 1992. It applies to shares and securities. It applies whether you are UK resident or not, as long as the transaction happens on a UK exchange or through a UK broker.

Here is the specific scenario that catches agency founders.

The ISA Trap: Selling Inside, Buying Outside

You hold shares worth £100,000 inside your Stocks and Shares ISA. They cost you £40,000. There is £60,000 of unrealised gain sitting inside the tax wrapper.

You are moving to Dubai. You will be non-resident. You know that once you are non-resident, you can sell those shares inside the ISA and the gain remains tax-free. But you also know that if you hold the shares outside the ISA in a general investment account, you could sell them later as a non-resident and potentially pay zero UK capital gains tax anyway (because non-residents generally do not pay UK CGT on most assets).

So you think: "I will sell the shares inside the ISA, take the cash out, and then immediately rebuy the same shares in a non-ISA account. That way I reset my cost base to the current market value. If I sell later, I only pay tax on the gain from today's price."

That is where the bed and breakfast rule hits you.

If you sell shares inside an ISA and then buy the same shares in a non-ISA account within 30 days, HMRC treats the sale as if it never happened. The original £40,000 cost base inside the ISA carries forward to the new holding. You do not get a fresh start at £100,000. You are still deemed to have a £40,000 base cost.

Worse, the gain inside the ISA was tax-free. But the new holding outside the ISA is now taxable. You have effectively moved a tax-free gain into a taxable environment without resetting the cost base.

Why Agency Founders Fall Into This Trap

This is not a niche issue. I see it most often with founders who have built up significant share portfolios inside their ISAs over years of high agency profits.

A typical scenario: a 35-year-old agency founder who has been maxing their ISA allowance for a decade. They have £200,000 in a Stocks and Shares ISA, mostly in a global tracker or a handful of tech stocks. They are selling their agency or stepping back from day-to-day operations. They are moving to Dubai for a lower-tax lifestyle.

Their accountant (or their online research) tells them: "You can keep your ISA. Just do not add to it."

But nobody tells them about the bed and breakfast rule. So they sell their ISA holdings, transfer the cash to a general investment account, and rebuy the same stocks the same day. They think they have tidied up their affairs. In reality, they have created a future tax liability that could cost them thousands.

What Happens If You Trigger the Rule

Let us run the numbers on a real example.

Before:

  • ISA holding: 10,000 shares in a global tracker, purchased at £4 per share. Cost base: £40,000.
  • Current value: £10 per share. Value: £100,000.
  • Unrealised gain: £60,000 (inside ISA, tax-free).

Your action:

  • Sell inside ISA at £10. Realise £100,000 cash. No tax due.
  • Withdraw £100,000 from ISA (allowed, but you lose the tax wrapper on that cash).
  • Buy 10,000 shares in the same global tracker at £10 in a general account. Cost: £100,000.

What you think happened:

  • Your new cost base is £100,000. If you sell later at £12, you pay CGT on £20,000 gain.

What actually happened (per HMRC):

  • Your new cost base is £40,000 (the original ISA cost base, carried forward).
  • If you sell later at £12, you pay CGT on £80,000 gain.
  • That £60,000 gain that was inside the ISA is now taxable.

At 24% CGT (the current higher rate for non-residential assets), that is £14,400 you did not expect to owe.

And because you are non-resident, you might assume you pay no UK CGT at all. That is generally true for assets you bought while non-resident. But HMRC treats the rebought shares as having the original cost base. The gain accrued while you were UK resident. The charge can still apply.

Does the Rule Apply If You Are Already Non-Resident?

Yes. The bed and breakfast rule is triggered by the transaction, not your residency status. If you sell shares in a UK ISA and buy the same shares in a UK general account within 30 days, the rule applies regardless of where you live.

If you are already non-resident and you do this, the same cost base carry-forward applies. You do not get a fresh start.

The only way to avoid it is to wait 31 days between the sale and the repurchase. Or buy a different share. Or use a different broker in a different jurisdiction (but that gets complicated with cross-border tax treaties).

What You Should Do Instead

If you are moving abroad and you hold a significant ISA portfolio, here is the practical approach.

Option 1: Leave the ISA Alone

This is the simplest. Keep the shares inside the ISA. Do not sell them. Do not withdraw the cash. The ISA stays open. The growth remains tax-free. You cannot add to it, but you do not need to do anything else. When you eventually sell the shares (inside the ISA), the gain is still tax-free. That is the whole point of the wrapper.

The downside: if you need the cash for a house purchase or living expenses, you have to withdraw it. But you can withdraw in tranches, keeping the tax wrapper on the remainder.

Option 2: Sell and Wait 31 Days

If you want to rebuy the same shares in a general account, sell the ISA holding, wait 31 days, then buy the shares in the general account. The bed and breakfast rule only applies within 30 days. Day 31 is safe.

Practical problem: the market can move significantly in 31 days. If the shares go up, you pay more to rebuy. If they go down, you get a better price but you also crystallise a loss inside the ISA (which you cannot use because the ISA is tax-free).

Option 3: Sell and Buy Something Different

The bed and breakfast rule only applies to "the same shares or securities". If you sell a global tracker and buy a different global tracker, or sell Apple and buy Microsoft, the rule does not apply. You get a fresh cost base.

This is the most practical workaround for most founders. You keep your market exposure but switch to a different fund or stock. Check the specific holdings are not "substantially the same", HMRC has challenged cases where the only difference was the provider. Stick to genuinely different assets.

Option 4: Transfer the ISA to a Non-UK Platform

Some international brokers accept ISA transfers from UK platforms. You keep the ISA wrapper but move the holdings to a broker that operates outside the UK. This can simplify reporting if you are non-resident. But not all UK ISAs can be transferred internationally. Check with your current provider and the receiving broker before doing anything.

What About the Dividend Allowance and CGT Allowance?

If you are non-resident, your UK dividend allowance (£500 for 2025/26) still applies to dividends from UK companies. Your CGT annual exempt amount (£3,000 for 2025/26) also applies. But these are small. If you have a significant portfolio, you will exceed them quickly.

As ICAEW qualified accountants, we advise founders moving abroad to get a full tax planning review before they leave. The bed and breakfast rule is just one of several traps that catch people who try to reorganise their affairs at the last minute.

Summary: The Rule in Plain English

  • You can keep your ISA when you move abroad. It stays tax-free.
  • If you sell shares inside the ISA and buy the same shares outside the ISA within 30 days, HMRC treats the sale as if it never happened.
  • Your original cost base carries forward. You do not reset it.
  • This can turn a tax-free gain into a taxable gain.
  • Wait 31 days, buy a different asset, or leave the ISA alone.

If your portfolio is over £50,000 and you are planning an international move, speak to your accountant before you trade. The bed and breakfast rule is easy to avoid once you know it exists. But if you trigger it by accident, unwinding it is difficult.