The gain Britain does not tax, and America treats as income

Figures relate to tax year 2025-26 (UK) · 2025 (US)

UK gilts escape capital gains tax in Britain. That one line has driven a great deal of buying in recent years.

Buy a low coupon gilt below par, hold it to maturity, and the pull back to par is a gain Britain does not tax at all.

However, America has no such exemption. Worse, it has a rule that turns that particular gain into ordinary income rather than a capital one.

Key takeaways

• UK gilts are exempt from British capital gains tax.
• The coupon is still taxable as interest here.
• America taxes both the coupon and the gain.
• Market discount rules make the gain ordinary income.
• Ordinary rates are higher than long term capital gains rates.
• There is no British tax on the gain to credit against it.
• Currency movement can add a further gain.
• The trade that works for a British investor can misfire badly.

Why are UK gilts exempt from capital gains tax?

Because the legislation says so. Per GOV.UK guidance on what capital gains tax applies to, UK gilts and most qualifying corporate bonds sit outside the charge. The policy reason is to keep government borrowing attractive to investors. Whatever the reason, the effect is that a gain on a gilt is simply not taxed in Britain.

The coupon is a different matter entirely.

That remains taxable as interest.

What is a low coupon gilt?

A bond paying a small annual rate, issued when rates were near zero. As market rates rose, those bonds fell well below their redemption value. So an investor can buy at eighty something and receive one hundred at maturity, with most of the return arriving as price movement rather than as income.

The return is mostly gain, not interest.

That is exactly the point of the trade.

Why do British investors like them?

Because the shape of the return is tax efficient here. A higher rate taxpayer pays income tax on a coupon but nothing on the pull to par. Converting taxable income into an untaxed gain is a legitimate and well understood piece of British planning.

Our guide to UK savings interest on a US return covers the interest side.

For a British investor it works cleanly.

What goes wrong for an American?

Two things at once. America taxes the gain, which Britain does not, so there is no British tax to credit against it. Then the market discount rules characterise that gain as ordinary income rather than capital, so it is taxed at your highest rates.

No credit, and the worst rate available.

That combination is unusually unkind.

What is market discount?

The gap between what you paid for a bond and what it will pay at maturity, where you bought it in the market below its redemption value. America treats that gap as deferred interest. So when you sell or redeem, the accrued portion is taxed as ordinary income rather than as a capital gain.

It is a character rule, not a timing rule.

The money is the same, the rate is not.

Is there a de minimis exception?

There is, and it saves small discounts. Where the discount is less than a quarter of one per cent of the redemption value for each full year to maturity, it is ignored and the gain stays capital. A deeply discounted long dated UK gilt will not come close to qualifying.

Short dated bonds bought near par can qualify.

The deep discount trade cannot.

A worked example

Take an illustrative example. An American in London buys £100,000 nominal of a low coupon gilt at a price of 84 in 2025.

At maturity she receives £100,000, so the pull to par is £16,000 plus the small coupons along the way.

Britain taxes the coupons and ignores the £16,000 entirely.

America taxes the coupons, then treats the £16,000 as ordinary income under the market discount rules, with no British tax available to credit against it.

One bond, two treatments

Can you elect to accrue it annually?

You can, and sometimes it helps. An election to include market discount as it accrues spreads the income across the holding period rather than bunching it at maturity. That can keep you out of a higher bracket in the final year, though it brings tax forward.

The election is generally binding going forward.

So take advice before making it.

Does currency make it worse?

It can, and it is measured separately. America works in dollars, so a gilt bought when the pound was weak and redeemed when it was strong produces a further dollar gain. That movement is part of the calculation rather than a side issue.

Our guide to exchange rates on a US return covers the method.

So the dollar result can differ sharply.

What about the investment income surcharge?

It can apply on top, and no foreign credit touches it. The net investment income tax is charged separately on investment income above a threshold, outside the treaty credit system. So a higher earner faces it on the coupons and potentially on the discount income too.

Our guide to the net investment income tax covers it.

This is the charge people never budget for.

Are index linked gilts different?

In Britain they enjoy the same capital gains exemption, so the uplift is untaxed here. America treats inflation adjusted bonds under its own rules, which generally tax the inflation uplift as it accrues rather than at maturity. So you can owe American tax on money you have not yet received.

Phantom income is the usual complaint.

So hold them somewhere sheltered if you can.

What about a gilt fund instead?

That is a different and usually worse problem. A British bond fund is a pooled investment, which brings the punitive American regime for foreign funds. Holding the gilts directly avoids that, so direct ownership is the lesser evil for an American.

Our guide to UK reporting fund status covers the funds.

Direct bonds beat bond funds here.

Does an ISA help?

Not for an American, and it removes what little relief existed. Britain already exempts the gain, so the wrapper adds nothing on that side, while America ignores the wrapper completely. You get the American charge either way and lose flexibility.

Our guide to ISA alternatives for Americans covers the wrappers.

The wrapper is wasted on gilts.

What about holding them in a pension?

That is the clean answer, as it usually is. A UK pension is recognised by the treaty, so income and growth inside it are generally left alone until you draw. UK gilts that are awkward in a dealing account are unremarkable inside a pension.

Our guide to UK pensions and US tax covers the treaty position.

Wrapper choice beats bond selection.

What if you sell before maturity?

The accrued discount to that date is still ordinary income, and anything beyond it is a capital gain. So selling early does not escape the character rule, it simply splits the profit into two parts. Britain continues to tax none of it.

Our guide to UK capital losses for US citizens covers losses.

Early sale changes the split, not the rule.

What if the gilt was bought above par?

Then the issue reverses and you have a premium rather than a discount. America allows an election to amortise bond premium against the interest, which reduces the taxable coupon over time. It is the mirror image and generally works in your favour.

High coupon UK gilts sit in this category.

So the trap is specific to discounted bonds.

Do these still suit an American at all?

They can, provided you buy them for the right reason. A gilt held for safety, duration or liquidity is a perfectly sensible holding. What does not survive contact with the American rules is buying one specifically because the gain is untaxed in Britain.

Buy them for the risk profile, not the wrapper.

The tax argument simply does not cross over.

What does your broker report?

Far less than an American broker would. A British platform shows contract notes and interest, but it will not calculate accrued market discount or issue American tax forms. So the computation falls to you or your preparer from the raw purchase data.

Keep every contract note.

The purchase price is the whole calculation.

How do you report it in America?

Interest goes with your other interest income, and the accrued discount is reported as interest on disposal. The remainder, if any, is a capital gain. Getting the split right is the part that takes the time, because no statement does it for you.

Our guide to Schedule B part three covers the disclosure.

Two lines from one transaction.

Does it count for account reporting?

The account holding them does, on the usual thresholds. UK gilts held through a British platform sit inside a foreign account, which counts towards the reporting limits. Holding them directly on the register is treated differently again.

Our guide to the FBAR covers the thresholds.

How you hold them changes the answer.

What records should you keep?

The contract note, the purchase price, the maturity value and the dates. Add the exchange rate on each date for the American side. Those five items are everything the calculation needs, and they are impossible to reconstruct later.

In our practice the purchase price is what goes missing.

Platforms purge old notes quietly.

Do UK gilts beat a cash deposit for an American?

Often not, once you allow for the character rule. A deposit pays interest taxed as interest in both countries, with British tax available to credit against the American charge. A discounted gilt produces ordinary income in America with no credit at all, so the after tax gap can run the wrong way.

So compare after tax, in dollars.

Because the headline yield misleads badly here.

What about UK gilts bought at issue?

Buying at par removes the market discount problem entirely, because there is no discount to accrue. The return then arrives as coupon, which both systems tax as interest, and British tax paid can be credited in the ordinary way. It is a far less awkward holding for an American.

So the primary market is friendlier than the secondary.

But the yield on offer may be lower.

Does it matter who holds them, you or your spouse?

A great deal, where one spouse is not American. Gilts held by a British husband or wife fall outside the American rules completely, so the pull to par stays untaxed on both sides. That makes ownership a deliberate planning decision rather than an administrative detail.

Our guide to joint accounts for US UK couples covers ownership.

But the gift itself needs thought first.

What if you move back to America holding them?

The American treatment carries on unchanged, since it never depended on where you lived. What disappears is the British exemption, because once you leave you may fall under different rules on disposal. So the holding becomes less attractive rather than more.

Our guide to moving back to the US covers the exit year.

So review the holding before you fly.

Are corporate bonds treated the same way?

In Britain many qualifying corporate bonds share the gilt exemption, so the same mismatch arises. America applies the market discount rules to them in exactly the same way, with no regard to the British treatment. The analysis therefore runs identically for a discounted corporate bond.

So the trap is not unique to government debt.

Because the American rule looks only at the discount.

How did this become such a common question?

Because rates rose quickly and a decade of low coupon issuance was suddenly trading far below par. British wealth managers spotted a clean, legitimate way to turn taxable income into an untaxed gain, and the idea spread fast. Americans living here were offered the same trade by advisers with no reason to think about the IRS at all.

So the advice was right, for the wrong investor.

In our practice it arrives as a done deal.

Can the position be unwound?

Partly, though not without cost. Selling before maturity still triggers the accrued discount as ordinary income, so there is no clean exit once the bond is held. What you can do is stop adding to the position and move future money into holdings that work on both sides of the Atlantic.

So the first step is to stop buying more.

Because the existing holding is largely baked in.

How to report UK gilts in America

1. Record the UK gilts purchase price and redemption value at the outset.
2. Work out whether the discount passes the de minimis test.
3. Decide whether to elect to accrue the discount annually.
4. Convert every figure to dollars on the relevant dates.
5. Report the coupons as interest in the year received.
6. Report accrued market discount as interest on sale or maturity.
7. Treat anything beyond the accrued discount as a capital gain.
8. Consider the investment income surcharge separately.

Mistakes and penalties we see with UK gilts

The first is assuming the British exemption means the gain is free everywhere.

The second is reporting the pull to par as a capital gain, which understates the tax.

The third is buying deeply discounted UK gilts specifically for a tax reason that does not apply to you.

The fourth is losing the original contract note, which makes the discount impossible to prove.

How US UK Tax Accountants helps

We model the after tax return across both systems before anything is bought, because the UK gilts trade that works for a British investor usually does not survive the American character rules.

Then we handle the split between interest and gain correctly. Our US federal returns service covers the filing.

If an adviser has suggested low coupon UK gilts, get in touch before you buy.

Last reviewed 22 October 2026. This article is general information and not personal tax advice, and rates and rules change each year.

For the neighbouring question, No withholding, no exemption, and a currency bill walks through it in detail.