Year-end planning when your household has two year ends

Year-end planning means making the decisions that stop being available once a tax year closes. Some allowances vanish if nobody uses them. Some elections only work in the year they apply to. And some transactions land in whichever year you finish them, whatever you intended.

Because the two countries measure a year differently. The US uses the calendar year, so its tax year runs to 31 December. The UK runs its personal year from 6 April to the following 5 April. That boundary dates from an eighteenth-century calendar reform, not from anything to do with tax.

So one UK tax year overlaps parts of two US ones. No moment exists when both systems close together. That means your planning never finishes on a single date.

Our guide to the UK tax year explains the mismatch in more detail. For year-end planning the practical consequence is simple. You need two checklists, and they do not hold the same items.

Most confusion here comes from applying a single-country checklist to a two-country position. An adviser who does that is not being careless. They are answering the question somebody asked them.

In short, year-end planning for this household means running two calendars at once. That sounds harder than it is. First you work out which calendar governs a given decision. Then you ignore the other one.

The American half of year-end planning. Anything the US calendar year measures stops moving at midnight on 31 December. No amount of activity in January changes which year a decision fell into. So three things matter most: gifts, disposals and estimated tax.

Charitable giving shows this clearly. A gift to a qualifying US organisation attracts relief in the year you make it. Therefore a donation on 30 December and one on 2 January land in different returns, sometimes at different rates.

Realised gains and losses behave the same way. The trade date decides the year. Telling your adviser in February changes nothing.

Estimated tax carries the sting. If withholding does not cover your US liability, payments fall due during the year. The IRS explains how estimated taxes work. Finding a shortfall in April does not undo it.

For example, a December bonus and a January bonus belong to different American years. So does a sale completed on either side of the boundary. In practice, year-end planning on this side is mostly about choosing which year an event lands in.

The British half. Several UK allowances run annually and do not carry forward. So an unused one simply disappears when the year turns, and no amount of goodwill brings it back. Three matter most for this audience: the ISA, the capital gains allowance and pension contributions.

The ISA subscription is the best known. Each tax year brings a fresh allowance, and GOV.UK sets out how ISAs work. Miss 5 April and you cannot use that year's allowance later.

The capital gains annual exempt amount works similarly. GOV.UK publishes the current allowance. A British adviser will often suggest realising gains up to it, so nothing goes to waste.

Pension contributions come third. The annual allowance carries its own rules, including limited carry forward. GOV.UK explains the annual allowance.

Crucially, none of these three allowances behave identically. The ISA disappears entirely. The capital gains allowance disappears too. However, pension carry forward gives you a second chance, which makes it the most forgiving item on the April list.

Because two staples of that advice assume only HMRC watches. Both work well for a British taxpayer. Both can cost real money for somebody who also files in the United States. The ISA causes one problem, and the capital gains allowance causes the other.

Take the ISA first. Britain treats the wrapper as tax-free, and the US does not recognise it at all. So what matters to the IRS is the contents. A stocks and shares ISA usually holds British funds, and those funds generally count as passive foreign investment companies.

Now take the capital gains allowance. Realising a gain inside it means little or no UK tax arises. That leaves nothing to credit against the American charge on the same gain.

So the manoeuvre can create a pure US cost out of nothing. Neither point makes the advice wrong in general. It makes it wrong for this household, which a single-country checklist cannot know.

No, and the blanket version of that advice helps nobody. What matters is the contents rather than the wrapper. A cash ISA earns interest, which an American reports and pays tax on as ordinary income. The British saving stays real, and nothing exotic happens.

A stocks and shares ISA differs sharply. British funds inside it bring the passive foreign investment company rules along with them.

Those rules carry a punitive default treatment and their own reporting. In practice the preparation cost often exceeds the British saving. Our guide to where Americans in Britain can hold investments works through the alternatives.

So the ISA question is really a contents question. Settle it before the subscription, not afterwards.

Mostly through relief. The British tax you pay in a year feeds the credit you claim against American tax on the same income. So anything that cuts your UK bill can quietly raise your US one, which surprises almost everybody the first time.

That deserves a moment. Cutting British tax does not automatically save money, because the American system would have absorbed that tax through a credit anyway.

The exclusion-versus-credit decision sits underneath all of it. Our comparison of the exclusion and the foreign tax credit sets out how that choice works.

None of this makes British relief pointless. It means you measure the saving across both returns, not the British one alone.

In other words, year-end planning across two systems is a netting exercise. You are not minimising either bill on its own. Instead you are minimising the combined cost, and those two goals genuinely diverge.

Settle anything whose year depends on a trade date or a payment date. That list runs shorter than people expect. However, every item on it becomes impossible on 1 January, so the deadline is real rather than advisory.

First, check your estimated tax position, especially if American withholding does not cover your income. Fixing a shortfall in November costs less than discovering it in April.

Second, decide on charitable gifts. A gift in December and a gift in January belong to different returns, and sometimes attract relief at different rates.

Third, review any planned investment sale. Moving a disposal by a fortnight can shift it into a year where your credit position works better.

Work through the British allowances that do not carry forward. However, test each one against the American consequence first. Treating them as free is the mistake that costs money, and it is the easiest one to make under time pressure.

Pension contributions usually survive that test well. So they tend to lead the British list for this audience.

The ISA subscription and the capital gains allowance both need checking first. Neither is automatically wrong, and neither is automatically free.

Finally, confirm your UK figures for the overlapping months. The American return will need them, so chasing them in December beats chasing them in October.

Earlier than most people manage. By December, half the American options have already narrowed. By March, the British ones get decided under time pressure instead of on the numbers. So autumn works far better than winter for this conversation.

October is a reasonable point to begin. Both years still stay open, which leaves time to model the credit position before anybody acts.

Starting late rarely triggers a penalty. Instead it produces a worse decision, taken quickly, which nobody notices and everybody pays for.

In our practice the households that do best treat this as an autumn conversation rather than a February scramble.

For instance, modelling the credit position takes a week once the figures arrive. Finding those figures takes longer. So an October start usually means a November decision, which still leaves both deadlines comfortably ahead.

Considerably. The year of a move brings part-year residence, split-year treatment and one-time elections all at once. So it carries more decisions than any later year, and more of them echo afterwards.

Those echoes last. Revoking the foreign earned income exclusion locks you out of it for several following years.

Accounts opened casually in the first month can create reporting that persists indefinitely. Therefore the year-end planning conversation and the first-filing conversation are really one conversation.

Our guide to your first year abroad covers the sequencing. If you plan to move, hold both conversations together.

That is the common case, and it changes the arithmetic. A US citizen married to a non-US spouse usually files separately. So the couple holds two different positions rather than one joint one, and each needs its own answer.

An allowance that suits the British spouse may not suit the American one. That makes asset ownership a planning question rather than an administrative detail.

Arranging it prospectively costs far less than unwinding it later. For example, moving an income-producing asset after the fact can itself trigger reporting.

This is also where coordinating two advisers matters most, because each one optimises for a different person.

Yes, sharply. A disposal of UK residential property carries a short British reporting window. Meanwhile the American gain needs its own computation, in dollars, on a different basis. So the timing of a sale matters twice, for different reasons.

A sale that suits you in April may suit neither return. Exchange rate movement between purchase and sale creates or removes American gain that never existed in sterling.

That is why the two computations rarely agree, and why a surprise usually appears on the American side.

So if a sale looks likely in the coming year, bring it into the year-end planning conversation early.

By collecting the underlying facts once and using them for both lists. The two checklists differ, but they draw on the same numbers. So one gathering exercise in the autumn serves both year ends perfectly well.

Account balances, disposals, contributions, donations and income by source cover most of what either side needs.

Our document checklist sets out what tends to matter. The deadline calendar keeps both countries in one view.

The households that find this painful usually reconstruct the same figures twice, months apart, from memory.

Similarly, year-end planning benefits from one shared file rather than two. When both advisers read the same numbers, the questions they ask each other get shorter. That alone removes most of the duplicated effort.

A workable sequence for a household inside both systems, starting in the autumn.

Consider an American working in London, married to a British spouse. She holds a workplace pension and a modest portfolio. Her British adviser sends the usual February note. Top up the ISA, realise gains up to the annual exempt amount, consider a pension contribution.

Two of those three work fine. The pension contribution suits both sides.

Realising gains to use the British allowance does not. It covers the gain in Britain, leaves nothing to credit, and hands her an American bill she would otherwise have avoided.

The ISA depends on what she buys. Cash stays unremarkable. However, British funds bring the PFIC regime, and the reporting costs more than the British saving.

These figures are illustrative. Importantly, her adviser was not wrong. The advice simply suited a taxpayer she is not, and year-end planning across two systems has to start from who the taxpayer actually is.

The most frequent one treats 5 April as the only year end. That usually happens because the British adviser sends the reminder. So the American list gets done in April, a year late.

The second assumes that cutting a British bill always saves money. Where a credit would have absorbed that tax anyway, the saving can vanish entirely.

The third acts on a single-country checklist without telling either adviser that the other exists. Both then optimise correctly for half a position.

The fourth leaves everything to the last fortnight. That turns a modelling exercise into a guess, and guesses in this area cost more than fees.

Finally, some households skip year-end planning entirely after a quiet year. That is usually reasonable. However, a quiet year is also the cheapest time to fix the structure before a noisy one arrives.

We work both lists on one file. So the British moves get tested against the American consequence before anybody acts, rather than afterwards.

In practice that means an autumn conversation, a model of the credit position on real figures, and a short list of decisions. Each one carries the date that actually closes it.

Our US federal returns service covers the American side, and fees stay fixed and agreed in writing after a scoping call. How we work sets out the process.

If you want both lists drawn up for your own position, talk to us and we will tell you which decisions remain open.