Why your foreign tax credits get stranded: Form 1116 income baskets explained

Figures relate to tax year 2025 (US)

You pay 40% tax in Britain and still end up owing the IRS. It feels like an error, and it usually is not. The cause is nearly always the income baskets on Form 1116, which keep credits apart even when the tax was real.

The form looks like one calculation. In fact it is several, run side by side. So this guide covers what the income baskets are and which British income belongs where. Then it covers why credits strand in one basket while tax falls due in another.

Key takeaways

• Form 1116 splits foreign income into separate categories, each with its own calculation.
• Salary and self-employment sit in the general basket; dividends and interest sit in the passive one.
• Credits in one basket cannot offset American tax in another.
• Each basket has its own carryback and carryforward, so excess credits are not lost immediately.
• The treaty can change where some income counts as arising, which changes the answer.
• A separate form is completed for each basket you have income in.

What is an income basket?

It is a category that separates one type of foreign income from another for credit purposes. Congress built them to stop people using heavy tax on one kind of income to shelter lightly taxed income of another kind. In practice they keep salary separate from investments.

Most people in Britain use only two income baskets. The general category covers earned income, and the passive category covers most investment income. Other categories exist but rarely apply to individuals.

Which British income goes where?

Salary, self-employment profit, rental profit and most pension income fall in the general category. Bank interest, dividends, capital gains on investments and similar returns fall in the passive category. The split follows the nature of the income, not the account holding the money.

Why do credits get stranded?

Because each basket stands on its own. Heavy British tax on salary produces surplus credits in the general basket, while American tax on dividends sits in the passive basket with little British tax behind it. The surplus cannot move across, so tax falls due anyway.

That is the whole explanation behind the question we hear most often. Paying 40% in Britain does not protect American tax on a dividend, because the two live in different columns.

In our practice this is the single most common reason a return shows a balance due. Nothing is wrong with the figures, and the answer lies in planning rather than in the arithmetic.

What happens to unused credits?

According to IRS guidance, they carry back one year and forward ten, within the same basket. So surplus general category credits sit waiting for a year with general category income taxed more lightly in Britain. Passive credits do the same in their own column.

Carryovers are worth tracking properly, because they expire quietly. A schedule showing the balance in each basket, year by year, takes minutes to maintain and can save thousands later.

Our guide to Form 1116 and the foreign tax credit covers the wider mechanics of the form, and our guide to UK dividends on a US return covers the passive side in detail.

How many forms do you actually file?

One for each income basket with income in it. A salaried American in Britain with a savings account files two: general for the salary, passive for the interest. Someone with only a salary files one. The count rises with the variety of income, not its size.

Each copy carries its own limitation calculation. That limitation compares American tax on the income in that basket with the foreign tax available, and the lower figure sets the credit.

So a basket with plenty of foreign tax and little American tax produces surplus credit. A basket with the reverse produces a bill.

What does the limitation actually measure?

Per the IRS instructions to the form, it measures how much American tax the foreign income in that basket produced. The credit cannot exceed that figure, however much foreign tax you paid. So the limitation, not the tax, usually decides the answer for people in Britain.

Deductions matter here more than people expect. Allocating expenses to a basket reduces the income in it, which reduces the limitation, which reduces the credit you can use.

A worked example

The figures below are illustrative. Take an example: an American in London earns a £95,000 salary taxed at British rates, and receives £6,000 of dividends from a US brokerage account.

The salary produces plenty of British tax, and more credits than the American tax on that income requires. The dividends are US-source, so no British tax attaches to them in the passive basket.

The surplus general credits stay where they are, and American tax on the dividends falls due in full. The return looks strange until you see the two columns side by side.

Does the treaty change the baskets?

It can change where income counts as arising, which affects the calculation. Some income that looks American can be re-sourced to Britain under the treaty, allowing British tax to support a credit against it. The income basket rules still apply to whatever remains.

You claim re-sourcing on a separate copy of the form, and it needs care. It remains one of the few levers when credits strand.

The high tax kickout

Passive income taxed heavily abroad can move into the general basket instead. The rule stops the passive basket filling up with high-taxed income. For British investors it occasionally helps, because it moves credits to where they do some good.

It applies automatically rather than by election when the conditions are met. So a return can show income in a basket you did not expect, for a reason that makes sense once traced.

Can planning move income between income baskets?

Not directly, but you can change what you hold. Someone with stranded general credits and a growing dividend problem can hold more of the portfolio in a pension, or shift toward growth rather than income. The income baskets then look different next year.

Timing helps too. Bringing a bonus into a year with spare passive tax, or delaying a disposal, can line the columns up better than any form ever will.

None of this beats the basic point. Check the income baskets before the year ends, not when the return is being prepared in October.

How to allocate income and tax correctly

Work from the source documents, not from a summary. Each item of income needs a category, and the tax paid must follow the income it relates to. Getting the tax allocation wrong is what produces most of the errors we correct.

1. List every item of foreign income for the year with its type and amount.
2. Assign each item to the general or passive category.
3. Allocate British tax to the income it actually relates to, including PAYE and Self Assessment.
4. Deduct expenses against the income they belong to, in the same basket.
5. Complete a separate Form 1116 for each basket with income.
6. Record any surplus credits in each basket and carry the schedule forward.
7. Review whether treaty re-sourcing would unlock any stranded credit.

What if you have no foreign tax at all in a basket?

Then no credit arises there, and the American tax stands. This is the position for US-source dividends and interest held while living in Britain. The income is American, no British tax attaches, and the passive basket has nothing to work with.

Treaty re-sourcing is the only common route around it. Failing that, the planning answer is to hold such assets differently, or accept the tax as the cost of the holding.

Common allocation errors

Splitting tax proportionally is the usual shortcut, and it is usually wrong. PAYE tax on salary belongs to the general basket in full. Tax paid on dividends through Self Assessment belongs to the passive basket.

Expenses follow the same logic. Costs against rental profit reduce general category income, and investment costs reduce passive income. Mixing them changes the limitation in each basket.

What if you use the exclusion as well?

Then the interaction needs care. Income excluded under the foreign earned income exclusion cannot also support a credit, and the related tax drops out of the calculation. That often leaves a smaller general basket than expected, with credits reduced to match.

For higher earners the credit-only route frequently produces a better result. Modeling both is worth an hour in any year with bonuses, equity or a change in income.

Do pensions sit in their own basket?

Pension income generally falls in the general category, alongside salary. Lump sums and drawdown payments follow the same logic, although the treaty position on pensions needs checking first. Where the treaty exempts income from American tax entirely, no credit question arises for it.

That interaction catches people at retirement. A year with both salary and pension income can produce a general basket far larger than any previous year, which changes what the credits cover.

What about state taxes and the baskets?

American state tax does not enter the federal calculation at all. Some states allow their own credit for foreign tax, and many do not. So a state return can show tax on income the federal return already sheltered through credits.

Anyone who kept a state filing obligation after moving abroad should check this separately. The federal income baskets tell you nothing about the state position.

Mistakes and penalties we see with income baskets

• Putting all foreign income on a single form and ignoring the categories.
• Allocating British tax across baskets on a proportional basis.
• Treating UK rental profit as passive income when it usually sits in the general basket.
• Losing track of carryovers, then discovering they expired.
• Missing the treaty re-sourcing option for US-source income taxed in Britain.
• Claiming credit for tax related to income excluded under the exclusion.

These errors rarely produce penalties on their own. They produce tax that never needed paying, year after year, which is a quieter and more expensive problem. Fixing the allocation in one year often unlocks credits that then carry forward for a decade, so the work pays for itself quickly.

How US UK Tax Accountants helps

We allocate every item to the right basket, track the carryovers, and check each year whether treaty re-sourcing helps. Where earlier returns lumped everything together, we rework them. If your return shows American tax despite heavy British tax, get in touch and we will review the baskets alongside our treaty relief work.

Last reviewed 23 September 2026. This article is general information and not personal tax advice. The categories and their rules change from time to time, so check the current instructions for your filing year.