CPA for American Expats in the UK: What to Look For

Choosing a CPA for American expats in the UK comes down to one test: can this person prepare a US return that correctly reflects a British life, with its ISAs, workplace pensions, HMRC payments and a tax year that ends on 5 April? A CPA licence proves US competence. The international forms, the treaty and the UK side of the file are learned separately, and plenty of excellent domestic CPAs have never needed to learn them.

This guide explains what the CPA credential does and does not cover, the knowledge an expat CPA must have, how to verify a preparer, what to expect to pay, and the warning signs. For the broader question of specialist versus generalist, see our pillar guide to tax specialists for US and UK filers.

What does a CPA licence actually certify?

Certified Public Accountant is a state licence. Each US state board of accountancy sets the exam, education and experience requirements, and the licence covers accounting, audit and tax within US law. The IRS recognizes CPAs, along with Enrolled Agents and attorneys, as having unlimited representation rights: they can represent you before the IRS on any matter, including audits and collections. The IRS explains the categories on its preparer credentials page.

What the licence does not certify is anything outside US law. There is no module on HMRC's Statutory Residence Test, no exam question on the SA109 residence pages, and no requirement to know that a UK stocks and shares ISA is a passive foreign investment company for US purposes. Those are specialist skills a CPA either has from experience or does not have at all.

Two practical rules follow. Anyone who prepares a US return for a fee, CPA or not, must hold an IRS Preparer Tax Identification Number and sign the return as paid preparer. And the IRS keeps a directory of credentialed preparers you can search by location, which is the quickest way to confirm a CPA is who they say they are.

Why does an American in the UK need more than a domestic CPA?

Because the US return of someone living in Britain is a different document from the return of someone living in Ohio. The income is the same kind of income, but almost every line interacts with a foreign system. Our guide to what Americans living in the UK must file lists the forms; the table below shows where a domestic preparer typically goes wrong.

Item on a UK life	Domestic CPA default	Expat CPA treatment
UK salary taxed under PAYE	Report it, pay US tax	Form 1116 credit or Form 2555 exclusion, modelled for your numbers
Stocks and shares ISA	"Tax-free account", ignored	Each fund is a PFIC; Form 8621 per fund
Workplace pension or SIPP	Ignored until withdrawal	Treaty position disclosed on Form 8833; reported on FBAR and Form 8938
UK current and savings accounts	Not asked about	FBAR if aggregate exceeds $10,000; Form 8938 above the abroad thresholds
National Insurance	Credited as foreign tax	Not creditable; the totalization agreement governs it
State of last residence	Assumed to have ended	Checked; California, New York and Virginia are slow to let go
UK Self Assessment	"Not my problem"	Prepared first so the UK tax figure on Form 1116 is real

The ISA line alone is reason enough. Our guide to why an ISA is a problem on a US return explains the punitive PFIC rules; a preparer who has never filed Form 8621 is not the right choice for someone who holds UK funds.

The knowledge an expat CPA must demonstrate

1. Foreign tax credit versus foreign earned income exclusion. Most UK employees do better with the credit because UK rates are higher than US rates and unused credits carry forward; the exclusion, $132,900 for 2026, suits some lower earners but can cost refundable child credits and locks you out for five years once revoked. The CPA should run both.
2. FBAR and Form 8938. The FBAR is due with the return, with an automatic extension to October 15, once non-US accounts exceed $10,000 in aggregate. Form 8938 applies for a single filer abroad above $200,000 at year end or $300,000 at any time, per the IRS comparison. See FBAR vs Form 8938.
3. PFICs. Form 8621, the excess distribution method, the mark-to-market election and how to restructure an ISA to avoid them.
4. The treaty. Article 17 and 18 on pensions, the saving clause, Form 8833 disclosures. Our post on when Form 8833 is required is a useful benchmark for what the CPA should already know.
5. Sequencing. The UK year ends on 5 April; the US return for the previous calendar year is due April 15, extended automatically to June 15 for citizens abroad and to October 15 with Form 4868. A UK-resident client's UK return is prepared first.
6. Catch-up. The Streamlined Foreign Offshore Procedures for non-willful late filers, and the delinquent FBAR submission procedures for people who filed returns but missed the form.

How does the UK side get handled when your preparer is a US CPA?

There are three models, and you should know which one you are buying. In the first, a single adviser holds both a US credential and a UK one, a CPA who is also a Chartered Tax Adviser, for example, and prepares both returns personally. It is the simplest arrangement and the rarest. In the second, one firm employs US-qualified and UK-qualified staff who work on the same file, share the account list and residence analysis, and review each other's returns before anything is filed. That is the model most genuine US/UK practices use, and it is how our own team is organised. In the third, a US CPA prepares the Form 1040 and refers the UK return to a separate firm, or vice versa. Both advisers may be excellent; the problem is that nobody owns the join. The UK tax figure that belongs on Form 1116 arrives by email as an estimate, the treaty position taken on the pension may differ between returns, and when a spouse who is not a US person needs a mirror return so that joint accounts reconcile, there is no one to prepare it.

Ask the CPA directly which model applies, and ask for the name of the UK-qualified person. If the honest answer is the third model, you can still proceed, but you should insist on one shared account list, one exchange-rate table and a written note of who prepares which return first. Our walkthrough of the US/UK cross border tax preparation process shows what the handoffs look like when they are done inside one team.

CPA, Enrolled Agent or both?

Enrolled Agents are licensed by the IRS itself and specialize in tax. They hold the same unlimited representation rights as CPAs. Many of the best expat preparers are EAs, and many expat practices mix CPAs and EAs on the US side. Treat the two as interchangeable for competence and ask the questions below of either. What is not interchangeable is a UK credential: for the UK return you want a Chartered Tax Adviser, ATT or chartered accountant on the same team. Our guide to CPA, EA, CTA and ATT credentials compares them.

Twelve questions to ask a CPA before you engage

1. Which state licensed you, and what is your PTIN?
2. How many clients do you have who live in the UK?
3. Who prepares the UK Self Assessment, and do they sit in your team?
4. Will you model Form 1116 against Form 2555 for my figures?
5. How do you handle the funds inside my ISA?
6. Will you file Form 8833 for my pension, and what position will you take?
7. How do you build the account list for the FBAR and Form 8938?
8. Which exchange rate method do you use, and is it documented?
9. Do you check my state residency position before I leave the US?
10. What is the fixed fee, and which forms does it include?
11. What is your turnaround in March and April?
12. Will you represent me if the IRS or HMRC raises a query?

What does a CPA for American expats in the UK cost?

Fees are driven by forms, not income. A straightforward Form 1040 with Form 1116 and an FBAR sits at the lower end; each PFIC, each state return, a UK company (Form 5471) or a Streamlined catch-up adds work. Our post on how much a cross border tax accountant costs gives market ranges, and how to read US UK tax accountant reviews explains what to verify. Two rules protect you: a fixed fee in writing before work starts, and a scope that names the forms. For your own quote, use our US tax return service page or get in touch.

Red flags

• A quote with no questions about accounts, pensions or ISAs.
• "Your ISA is tax free."
• Unfamiliarity with Form 8621 or Form 8833.
• Advice to skip the FBAR because no tax is due.
• National Insurance credited as income tax.
• No PTIN, or reluctance to say who signs the return.
• "We have a contact in London" instead of a named UK adviser on the file.
• No written fixed fee.

Illustrative example: an American product manager in London has PAYE salary, a stocks and shares ISA holding three UK funds, a workplace pension and two UK bank accounts. A domestic CPA prepares a Form 1040 with Form 2555, ignores the ISA and files no FBAR. An expat CPA prepares Form 1116 instead because UK tax exceeds the US liability, files three Forms 8621, discloses the pension on Form 8833, reports all four accounts and the pension on the FBAR and checks the Form 8938 thresholds. The second return costs more to prepare and far less to defend. This is illustrative only; the right treatment depends on the actual facts.

The bottom line

Look for a CPA, or an Enrolled Agent, who can answer the twelve questions without hesitation, who has a named UK-qualified colleague on the same file, and who puts the fee in writing. Verify the licence and PTIN before you send a document. Our guide to accountants for US and UK taxes covers the full engagement, and our offices in London, Manchester, New York and San Francisco work as one team on both returns.