Renouncing US Citizenship: The Tax Implications Explained

Renouncing US citizenship doesn't trigger a tax bill by itself. A separate test decides that: whether you count as a "covered expatriate" under Section 877A. Most long-term expats with ordinary savings and a house never cross that line. People with significant assets, a high income history, or messy prior filings need to check carefully before they book the embassy appointment, not after.

What is the exit tax, technically?

The exit tax is the informal name for the tax consequences under Internal Revenue Code Section 877A that can apply when a US citizen renounces citizenship or a long-term green card holder gives up permanent residency. It isn't a separate tax return or a flat fee — it's triggered through your final expatriation-year filing, using Form 8854, and it only bites if you're classified as a covered expatriate.

Who actually becomes a "covered expatriate"?

You're a covered expatriate if you meet any one of three tests as of your expatriation date:

• The net worth test: your worldwide net worth is at or above a threshold that Congress fixed at $2 million and does not adjust for inflation.
• The average income tax liability test: your average annual US federal income tax liability for the five years before expatriation exceeds an amount that the IRS adjusts for inflation each year. Check the current-year figure directly on the IRS's expatriation tax page before assuming last year's number still applies.
• The certification test: you fail to certify, under penalty of perjury on Form 8854, that you've complied with all US federal tax obligations for the five years before expatriation.

That third test is why Form 8854 matters so much — even someone comfortably below both the net worth and income thresholds becomes covered simply by filing incompletely or having genuine gaps in prior-year compliance. A dual citizen from birth who never lived in the US and never had a filing requirement can be exempt from covered-expatriate status entirely under a separate carve-out, but the paperwork to claim it still has to be done correctly.

If you are covered, what gets taxed?

The core mechanism is a deemed sale: for most property you own, the IRS treats you as if you sold everything at fair market value the day before you expatriated, and taxes any resulting gain as if it were realized that year. An annually adjusted exclusion amount shields a first slice of gain from tax — again, confirm the exact current-year figure on IRS.gov rather than relying on a number from a prior tax year, since it moves with inflation adjustments every year.

Three categories are carved out of the mark-to-market approach and taxed differently instead:

• Deferred compensation items (certain employer retirement and stock plans) — typically subject to 30% withholding when eventually distributed, or accelerated income recognition depending on the plan type.
• Specified tax-deferred accounts such as traditional IRAs — treated as fully distributed on the day before expatriation, with ordinary tax consequences.
• Interests in nongrantor trusts — future distributions to the (now former) US person carry a 30% withholding tax on the taxable portion.

Illustrative example: a long-term US citizen in the UK with a UK-only investment portfolio, no US retirement accounts, and net worth comfortably under $2 million generally isn't a covered expatriate at all — the mark-to-market rules simply don't apply to them, provided Form 8854 is filed correctly and certifies five clean years. This is illustrative only; it depends entirely on your own facts.

What Form 8854 actually requires

Form 8854 does three jobs at once: it notifies the IRS that you've expatriated, it certifies your five-year compliance history, and — for covered expatriates — it calculates the exit tax itself. It's filed with your final return for the expatriation year, which is usually a dual-status return covering part of the year as a citizen and part as a nonresident.

Getting the timing and the certification right matters more than almost anything else in this process. An incomplete or late Form 8854 doesn't just risk penalties — it can independently make you a covered expatriate under the certification test, even if your net worth and income history would otherwise have kept you out of that category entirely.

Does the tax story really end at expatriation?

Not quite. Two things can still reach you afterward:

1. The expatriation year itself is split — you file as a citizen for the part of the year before renouncing and as a nonresident for the part after, each with its own reporting rules.
2. The "covered gift or bequest" rule can tax a US person who later receives a gift or inheritance from a covered expatriate, at the top estate/gift tax rate applicable at the time, regardless of how long after expatriation the transfer happens. This is a tax on the US recipient, not the person who expatriated, and it's easy to overlook when family members plan gifts across the Atlantic.

What doesn't change on the UK side

Renouncing US citizenship has no automatic effect on UK tax residency or HMRC's claim on your income and gains. If you're UK tax resident, you keep filing and paying under ordinary UK rules exactly as before. What changes going forward is simpler: your UK-situs assets stop being part of any future US net worth or mark-to-market calculation, because there's no longer a US filing obligation to trigger one. For the treaty-relief and pension questions that come up around the same time as an expatriation decision, our treaty relief service and US/UK pensions service cover the adjacent ground.

The bottom line

Don't let the word "exit tax" imply a bill is coming automatically — for most long-term expats with UK-level assets, it isn't. What actually creates risk is the paperwork: getting the net worth and income tests analyzed correctly beforehand, and filing a complete, accurate Form 8854 on time. Both are worth getting a second opinion on before, not after, the appointment at the embassy.