US-UK Tax Specialists for High Earners in New York

High earners with feet in both Manhattan and the UK face two tax systems that rarely agree. US-UK tax specialists at New York firms bridge that gap, combining American federal and New York rules with UK Self Assessment. Hence, one adviser handles FBAR, the treaty, and NYC residency without leaving gaps that trigger penalties.

By the TaxYork US-UK Tax Team — reviewed by a US-UK dual-qualified adviser (CPA / Enrolled Agent).

If you are a British banker on a Manhattan trading floor, an American with rental flats in London, or a dual citizen splitting the year between the two cities, your return is not a single-country problem. It is a coordination problem. The Internal Revenue Service taxes US citizens and green card holders on worldwide income, regardless of where they live. New York State and New York City layer their own aggressive residency rules on top. And HM Revenue & Customs still wants its share of anything UK-sourced. If you omit a disclosure form, which has a five-figure penalty on its own, or if the sequencing is incorrect, you will pay tax twice.

This guide explains what a genuine cross-border adviser does, why New York deserves its own line of defense, and how to distinguish real specialists from generalists who only see part of the picture. For a broader framework, see our companion piece on how to choose a US-UK tax adviser.

Who actually needs a cross-border adviser in New York?

The client base is narrower and wealthier than most tax practices realize. It includes UK nationals relocated to New York on finance, law, or tech packages; Americans who lived in London and returned with UK pensions, ISAs, or buy-to-let property; and lifelong dual citizens who never chose either passport. The common thread is money moving across the Atlantic — salary, bonuses, equity, rental income, inheritances — each with a different tax home.

These clients share three headaches. First, they are taxed by more authorities than a purely domestic earner. Second, their assets often sit in structures that are ordinary in the UK but toxic under US rules, such as ISAs and UK funds. Third, the reporting burden is enormous, and the penalties for missing a form dwarf the tax at stake. That combination is precisely why US-UK tax specialists and New York households turn to advisers who live in both countries daily.

What to look for in US-UK tax specialists New York clients can trust

Credentials come first. A genuine specialist holds a US qualification — a licensed Certified Public Accountant (CPA) and/or an IRS Enrolled Agent, the federally authorized designation to represent taxpayers before the IRS — and a UK qualification such as ACA, ACCA, or the Chartered Tax Adviser (CTA) credential. One side alone is not enough. A US-only preparer will miss the UK angle; a UK-only accountant cannot sign a US return. The best US-UK tax specialists in New York firms keep both credentials under one roof, so nothing falls between two desks.

Ask about useful machinery instead of just the letters that follow a name. A preparer must hold a valid Preparer Tax Identification Number (PTIN) and be authorized for IRS e-file. They should be fluent in the disclosure forms below, and — crucially for Manhattan — in New York State and New York City rules, not just the federal return.

The federal reporting stack

Three overlapping regimes catch almost every cross-border client:

• FBAR (FinCEN Form 114). Required when your foreign financial accounts exceed USD 10,000 in aggregate at any point in the year. It is filed with the Treasury's Financial Crimes Enforcement Network, not the IRS, and the civil penalties for willful failure are severe. Our detailed breakdown of FBAR penalties explains the exposure.
• Form 8938 (FATCA). The statement of specified foreign financial assets, filed with your 1040. It covers a wider asset base than the FBAR — including directly held foreign stock and interests in foreign entities — with thresholds that rise for taxpayers living abroad.
• PFIC reporting (Form 8621). The trap that catches Brits most often. UK unit trusts, OEICs, and most UK-domiciled ETFs are Passive Foreign Investment Companies under US law. Each one may need a separate Form 8621, and the default tax treatment is punitive. A single stocks-and-shares ISA can generate a stack of these forms.

The treaty and foreign tax credit

The US-UK income tax treaty is the instrument that stops the same pound being taxed twice. Used properly — alongside the foreign tax credit on Form 1116 — it assigns taxing rights, protects pensions, and relieves double taxation. There is also a separate US-UK estate and gift tax treaty that matters enormously for high earners with property and investments in both jurisdictions, because the US estate tax can reach assets that a domiciled person would never expect to be subject to it. We unpack the mechanics in our US-UK tax treaty explainer.

Why New York deserves its own defense

Federal compliance is only half the job in Manhattan. New York is one of the most aggressive states in the country on residency, and it runs two independent tests. You are taxed as a resident if New York is your domicile, or — even if you are domiciled in London or Florida — if you keep a permanent place of abode in New York and spend more than 183 days there in the year. A day is any portion of a day. The state's own residency FAQs confirm how the statutory-residence test bites, and audits are common and document-heavy. Our guide to New York residency tax walks through how to defend a day count.

Then there is New York City's own personal income tax, charged on top of state tax for city residents, and the notorious "convenience of the employer" rule. Under that rule, if you work remotely from outside New York for your own convenience rather than your employer's necessity, New York still treats those days as New York workdays and taxes the wages. In May 2025, the New York Tax Appeals Tribunal upheld the rule again, so a London-based employee of a New York firm can find their salary subject to it. This is where a lot of foreign tax credit planning goes wrong: New York does not always give credit that lines up with the foreign tax, so a mismatch leaves income taxed twice. Sound US-UK tax specialists, in New York, model the state and city position before the year closes, not after.

Social security, pensions, and equity comp

Two more areas separate specialists from generalists. The US-UK totalization agreement coordinates Social Security and National Insurance so that a worker on assignment is not charged to both systems, using a Certificate of Coverage to determine which system's contributions apply. And for Wall Street clients, deferred compensation and equity awards — RSUs, options, carried interest — must be sourced correctly across the period they were earned, which often straddles a London posting and a New York one. UK-side reporting still runs through HMRC Self Assessment, and the two filings must tell a consistent story.

A checklist for vetting an adviser

What to look for

Why it matters

Red flag

US CPA or IRS Enrolled Agent

Legal authority to prepare and represent before the IRS

"Bookkeeper" who subcontracts the US return

UK ACA / ACCA / CTA

Competent to sign off on the Self Assessment and UK planning

US-only firm that "partners" loosely with a UK accountant

Valid PTIN + IRS e-file

Confirms an active, authorized federal preparer

Paper-only filing or no PTIN on the return

New York State & City expertise

Handles statutory residency and the convenience rule

An adviser who only files the federal 1040

FBAR, 8938, PFIC fluency

Prevents five-figure disclosure penalties

Never mention your ISA or UK funds

Streamlined Filing Experience

Fixes past non-compliance the correct way

Suggests a "quiet disclosure"

That last row is the brightest red flag of all. If you have fallen behind on filings — common for people who did not realize US citizens file wherever they live — the correct fix for non-wilful cases is the IRS Streamlined Filing Compliance Procedures, which we cover in depth in our note on the streamlined foreign offshore procedures. Any adviser who instead proposes quietly filing amended returns and hoping nobody notices is exposing you to far worse penalties. Walk away.

Case study: a London banker's first New York season

Consider "James," a British managing director relocated from a City bank to its Midtown desk in March. He kept his Fulham flat, rented a condo in Tribeca, and assumed his employer's payroll had him covered. It had not. By December, he had spent 210 days in New York with a permanent place of abode — a textbook statutory resident, taxed by New York on worldwide income, including his UK rental income. His stocks-and-shares ISA, which he treated as tax-free, was a basket of PFICs demanding multiple Forms 8621. His unfiled FBAR covered a UK current account, a savings pot, and a pension.

A coordinated review fixed the sequence: UK tax paid first, then claimed as a foreign tax credit on the US return, with the treaty protecting his pension and the totalization agreement keeping him out of double social security charges. The ISA was restructured going forward, the back FBARs brought current, and his New York day count documented for audit. The lesson high earners take from cases like James's is why US-UK tax specialists at New York firms earn their fees: the coordination, not any single form, is the value.

Work with TaxYork

TaxYork is a team of dual-qualified US-UK tax specialists serving New York high earners remotely, from first-year relocations to complex equity and estate planning. If you want one adviser who owns the whole picture — federal, state, city, and UK — talk to us. Email hello@taxyork.com, call 020 3488 8606, or visit taxyork.com to arrange a confidential review before your next filing deadline.