Questions to Ask a US-UK Tax Adviser Before You Hire One

Choosing a US–UK tax adviser comes down to five checks: who is licensed to sign your US return, whether the same firm prepares the UK one, how they handle treaty positions, what the engagement actually covers, and how the fee is quoted. Get those answers in writing before you hire.

Most cross-border problems we see were not caused by aggressive planning. They were caused by a competent US preparer who did not see the UK side, or a competent UK accountant who did not see the US side, each doing half the job correctly.

1. Who signs the return, and what licence do they hold?

Anyone paid to prepare a US federal return needs a Preparer Tax Identification Number, but only certain credentials carry unlimited rights to represent you before the IRS: an enrolled agent, a CPA or an attorney. The IRS explains the differences in its guidance on choosing a tax professional.

Ask who will actually sign, and what happens if the IRS writes. A firm that cannot represent you is a firm you will have to replace at the worst possible moment. The credential comparison is in enrolled agent vs CPA vs chartered accountant.

2. Does the same firm do both returns?

The UK and US returns are not independent. The foreign tax credit on the US return depends on the UK liability; the UK return may depend on US figures. When two firms prepare them separately, figures get estimated, and estimates drift.

3. How do they handle treaty positions?

Ask how they would treat a UK pension, a 25% lump sum, US dividends taxed by HMRC, and employer pension contributions. You are not testing for a particular answer; you are testing whether they reason from the treaty articles and the saving clause or from habit.

Three answers should make you pause. "The treaty means you only pay tax once" is a slogan, not an analysis — the saving clause means US citizens frequently pay twice before relief. "We just use the exclusion for everyone" ignores the credit comparison that decides child tax credits and IRA contributions. And "your UK accountant handles that side" is only reassuring if someone has checked that they do.

A good answer names the article and says where the position is uncertain. Our own treatment of the hardest one is in the UK 25% pension lump sum and US tax.

4. What does the engagement actually include?

• Which returns and years: Form 1040, FBAR, Form 8938, UK Self Assessment.
• Information returns that often cost extra: Forms 8621, 5471, 3520 and 8833.
• Who files the FBAR, and whether it is in the fee.
• Whether IRS or HMRC correspondence is included or billed separately.
• Who holds the filing deadlines and extensions — see US expat tax deadlines.
• Turnaround times, and what happens if UK figures arrive late.

Ask for a fixed quote against a defined scope rather than an hourly estimate. Where the scope genuinely cannot be known until the records are reviewed — catch-up filings, for instance — ask for a capped review fee first.

5. How do they price catch-up work?

If you are behind, the answer should distinguish between the streamlined procedures, delinquent FBAR filing and an ordinary amendment, because the work and the risk differ. An adviser who recommends the streamlined route before seeing why you did not file is guessing — the certification is a sworn statement, covered in Form 14653 and the non-willful certification.

Practical checks before you hire an adviser

Confirm the firm carries professional indemnity insurance, ask how many US–UK clients they handle rather than expat clients generally, and check who does the work — the named partner or an offshore preparation team. Ask how records are shared and where your data is stored.

Continuity matters more than most people expect. Cross-border positions carry forward for years — credit carryovers, depreciation schedules, pension basis, elections that cannot be revoked without consequence — so an adviser who cannot produce last year's workings will rebuild them at your cost. Ask what you receive at the end of an engagement, and whether the supporting schedules come with it.

In the UK you can also authorise an agent to deal with HMRC on your behalf, which GOV.UK describes in its guidance on appointing someone to deal with HMRC. The equivalent US authority is Form 2848 for representation or Form 8821 for information access.

Tranzesta prepares both returns in-house, quotes fixed fees against a written scope, and sets out treaty positions before filing rather than after a query. Book a consultation to ask us these questions directly. The routine return work is described under US expat tax returns.

Frequently Asked Questions

What should I ask a US–UK tax adviser before hiring?

Ask who signs the return and what credential they hold, whether the same firm prepares the UK return, how they approach treaty positions such as pensions and re-sourcing, exactly which forms the fee covers, and how correspondence with the IRS or HMRC is charged. Get the answers in a written engagement letter.

Do I need a CPA, or will an enrolled agent do?

Either can prepare your return and represent you before the IRS without limitation, as can an attorney. Enrolled agents are licensed specifically in taxation, while CPAs cover a broader accounting remit. What matters more for cross-border work is demonstrable US–UK experience and access to qualified UK advice.

Is one firm for both countries better than two?

Usually yes, because the two returns interact: the foreign tax credit depends on the UK liability, and elections on one side change the other. Two firms can work well if they communicate and one clearly owns the credit calculation, but split responsibility is where double taxation and missed elections tend to appear.

What should a fixed fee include?

At minimum the federal return, the FBAR and the UK Self Assessment return if you need one. Information returns such as Forms 8621, 5471, 3520 and 8833 are commonly extra, so ask for them to be priced separately in advance rather than discovered later, along with the cost of responding to notices.

How do I check someone is registered?

Paid US preparers must hold a Preparer Tax Identification Number, and the IRS publishes a directory of preparers with recognised credentials. In the UK, ask which professional body the firm belongs to, and confirm the agent authorisation you are asked to give covers only what you intend.

Does the same apply to a US–UAE adviser?

The checks are the same, with one difference: there is no US–UAE income tax treaty, so there are no treaty positions to test. Focus instead on their experience with the foreign earned income exclusion, UAE corporate tax registration, and the controlled foreign corporation rules for free zone companies.