HMRC now receives automatic data on overseas bank accounts, investments and assets from more than 100 countries every year. If you have undisclosed offshore income or assets, HMRC almost certainly already holds information about them. Understanding how that data reaches HMRC and what to do about it, can be the difference between a voluntary settlement and a full investigation with penalties up to 200%.
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What triggers an HMRC offshore investigation
HMRC does not rely on chance to identify offshore non-compliance. It deploys several systematic data sources, and the combination of these has transformed HMRC’s ability to detect undisclosed foreign income and assets.
Common Reporting Standard and FATCA data exchange
The most significant development of the past decade is the automatic exchange of financial account information under the Common Reporting Standard (CRS) and the US’s equivalent Foreign Account Tax Compliance Act (FATCA). Under these frameworks, foreign financial institutions identify UK-resident account holders and report their account details, balances, income, proceeds from asset sales, to their local tax authority. That authority then transmits the data to HMRC, typically once per year.
For tax years from 2016–17 onwards, HMRC has been receiving this data in bulk. Over 100 jurisdictions now participate in CRS. The result is that a Swiss savings account, a Dubai investment account or a Cayman Islands trust holding is no longer “invisible” to HMRC.
HMRC Connect: the matching engine
HMRC’s Connect system is a sophisticated data analytics platform that ingests CRS and FATCA data and cross-references it against every UK taxpayer’s Self Assessment returns, PAYE records and National Insurance numbers. Where Connect identifies a discrepancy, for example, a foreign account with income not declared on the UK return, it flags the case for compliance action. This is the primary route by which offshore disclosure letters are generated.
Informants and whistleblowers
HMRC operates a confidential reporting line and pays rewards for information leading to recovered tax. Disgruntled business partners, former employees and family members have all provided information that triggered offshore investigations. HMRC does not rely exclusively on automated data, human intelligence still plays a role.
Historic campaign data
Before CRS, HMRC ran targeted campaigns, the Liechtenstein Disclosure Facility, the Swiss-UK Tax Agreement, the Crown Dependencies campaigns, that yielded data on offshore accounts. Taxpayers identified during those campaigns but who did not disclose remain on HMRC’s radar. More recently, leaked data sets (Swiss Leaks, Panama Papers, Pandora Papers) have added further names to HMRC’s target list.
What CRS covers
CRS was developed by the OECD and has been adopted by over 100 jurisdictions since 2016. UK implementation began with the first exchanges taking place in 2017 (covering data from tax year 2015–16 in CRS-early-adopter countries).
Under CRS, foreign financial institutions report the following information to their tax authority (which passes it to HMRC) for each UK-resident account holder:
- Account balances at the end of the reporting year
- Interest and dividends credited to the account
- Gross proceeds from the sale or redemption of financial assets
- Account holder identity data: name, address, date of birth and tax identification number (National Insurance number or UTR for UK persons)
What HMRC receives is, in many cases, more detailed than what a taxpayer declares on their Self Assessment return. The matching process therefore routinely identifies under-declarations of foreign interest, dividends and capital gains.
FATCA: the US dimension
FATCA operates in parallel with CRS. Under the UK–US Intergovernmental Agreement, US financial institutions report to the IRS on accounts held by UK persons and the IRS passes this data to HMRC. The reverse also applies, UK financial institutions report on US persons’ accounts to HMRC, which shares with the IRS. For UK taxpayers with US brokerage accounts, retirement accounts (such as 401(k) and IRA plans) or US real estate, HMRC will typically have data.
The Requirement to Correct
The Finance Act 2017 introduced a Requirement to Correct (RTC) , a legal obligation on UK taxpayers to correct any pre-6 April 2017 offshore non-compliance by 30 September 2018. The deadline has now passed.
Anyone who had undisclosed offshore tax liabilities arising before April 2017 and did not correct them by the September 2018 deadline is potentially subject to the Failure to Correct (FTC) penalty regime under Schedule 18 Finance Act 2017. FTC penalties are severe: between 100% and 200% of the tax, even for Category 1 (best-exchanging) territories, substantially higher than the standard offshore penalty rates. A “serious default” FTC penalty can also attract an additional asset-based charge.
It is therefore critically important to take specialist advice if you believe you may have pre-2017 offshore non-compliance that was not corrected by September 2018. The FTC regime does contain a reasonable excuse defence, but it is narrowly interpreted.
Offshore penalties under FA 2015 Schedule 20
The FA 2015 Schedule 20 regime overlays the standard behaviour-based penalty framework (Schedule 24 FA 2007) with higher percentages for offshore matters. Penalties are calculated by reference to two variables: the territory category of the relevant jurisdiction and the behaviour involved.
Territory categories
- Category 1: Jurisdictions that have full exchange of information arrangements with the UK, EU member states, the US, Australia, Canada and most major economies. Lowest penalty rates.
- Category 2: Jurisdictions with a partial or developing exchange relationship, some Caribbean territories, certain Gulf states. Mid-range penalty rates.
- Category 3: Jurisdictions with no or minimal, exchange of information with the UK. Highest penalty rates.
Penalty percentages
The table below sets out standard penalty ranges for offshore failures. These are percentages of the unpaid tax:
| Behaviour | Cat 1 (unprompted) | Cat 2 (unprompted) | Cat 3 (unprompted) | Cat 3 (prompted) |
|---|---|---|---|---|
| Careless | 30% | 60% | 100% | 150% |
| Deliberate | 70% | 105% | 140% | 200% |
| Deliberate & concealed | 100% | 150% | 200% | 200% |
The asset-based penalty
For “serious defaults”, essentially, deliberate and concealed offshore failures, paragraph 4 of Schedule 20 FA 2015 allows HMRC to charge an additional asset-based penalty of up to 10% of the value of the relevant offshore asset per year, for up to three years. This charge is levied in addition to the tax-geared penalty and can therefore represent a very substantial additional liability for high-value offshore holdings.
The Worldwide Disclosure Facility
The Worldwide Disclosure Facility (WDF) is HMRC’s current voluntary disclosure route for offshore non-compliance. It is a permanent online portal at Gov.uk, available to any UK taxpayer who wishes to disclose undisclosed offshore income, gains, assets or liabilities, whether held directly, through a trust, through a company or otherwise.
The key benefit of using the WDF is the ability to obtain unprompted or prompted disclosure penalty rates (lower than HMRC-initiated investigation rates) and to reduce the risk of criminal prosecution referral. Specifically:
- Disclosing before HMRC has made contact is treated as an unprompted disclosure, giving the maximum penalty reduction available.
- Disclosing after a nudge letter but before a formal investigation is treated as a prompted disclosure, still substantially lower than penalties arising from an HMRC-initiated enquiry.
- The quality of disclosure (how fully you tell HMRC what happened, how much you help them verify figures and how much access you give to records) further reduces the final penalty.
The WDF also involves a 30-day notification period: a taxpayer can register an intent to disclose on the Gov.uk portal, giving themselves 30 days to prepare the full disclosure. Acting quickly after receiving any offshore nudge letter is therefore essential to take full advantage of this window.
For a detailed walkthrough of the WDF process, see our guide: The Worldwide Disclosure Facility Explained.
Reasonable excuse and reasonable care
Offshore penalties can be reduced or eliminated where a taxpayer demonstrates either reasonable excuse (for the underlying failure) or reasonable care (which prevents a careless behaviour categorisation in the first place).
What works
- Reliance on professional advice: if a qualified tax adviser told you the income was not taxable in the UK and that advice was reasonable in the circumstances, this can constitute reasonable excuse or demonstrate reasonable care.
- Genuine misunderstanding of foreign law: for example, if you genuinely believed that a foreign jurisdiction’s taxation of income at source meant the UK had no further claim, this may be relevant (though HMRC scrutinises such claims carefully).
- Circumstances beyond your control: bereavement, serious illness or the destruction of records can support a reasonable excuse.
What does not work
- Ignorance of UK tax obligations: “I didn’t know I had to declare foreign income” is not, in itself, a reasonable excuse, UK residents are expected to understand their basic tax obligations.
- Reliance on an unqualified person: depending on a friend or family member rather than a professional adviser does not constitute reasonable reliance on professional advice.
- Failure to check: taking no steps to enquire about your obligations when you knew you had offshore assets is unlikely to succeed as a defence.
From nudge letter to full investigation
HMRC’s offshore compliance process typically follows a stepped escalation:
- Nudge letter: HMRC has CRS or other data suggesting offshore income or assets. It writes to prompt voluntary disclosure. This is a non-statutory compliance check, not a formal enquiry.
- Follow-up nudge or formal check: if no response is received within the time given (often 30 days), HMRC may send a second letter or escalate to an informal compliance check letter requesting information.
- Formal enquiry: HMRC opens a formal enquiry under s9A TMA 1970 (for income tax) or s12AC TMA 1970 (for partnerships) or issues a discovery assessment. At this point, the matter is no longer a nudge, it is an investigation and the “unprompted” penalty window has closed.
- Civil investigation or COP9: in the most serious cases, particularly where deliberate offshore concealment is suspected, HMRC may escalate to a formal civil fraud investigation under Code of Practice 9.
Frequently asked questions
Does HMRC know about my foreign bank account?
Almost certainly, if the account is held in one of the 100+ jurisdictions participating in CRS. HMRC’s Connect system matches automatically exchanged data against UK tax returns. Discrepancies generate compliance action. See our guide to the Common Reporting Standard for a full explanation of what HMRC receives and how it uses the data.
What is the penalty for undisclosed offshore income?
Penalties under FA 2015 Schedule 20 range from 30% (careless, Category 1 territory, unprompted disclosure) to 200% (deliberate and concealed, Category 3 territory, prompted or no disclosure). On top of these tax-geared penalties, HMRC can charge an asset-based penalty of up to 10% of the asset value per year for up to three years in serious cases. See our offshore penalty framework guide for the full table of rates.
Can I still make a voluntary disclosure if HMRC has already contacted me?
Yes, if HMRC’s contact has been by way of a nudge letter or informal compliance check rather than a formal enquiry letter or discovery assessment for the same matter. Using the Worldwide Disclosure Facility after a nudge letter still qualifies as a prompted disclosure and attracts substantially lower penalties than an HMRC-initiated full investigation. See our guide to the Worldwide Disclosure Facility for eligibility details.
What is the asset-based penalty?
The asset-based penalty (paragraph 4 of Schedule 20 FA 2015) is an additional charge that HMRC can levy on serious offshore defaults. It is up to 10% of the market value of the relevant offshore asset per year of the default, for a maximum of three years, meaning a potential additional charge of up to 30% of the asset’s value. It is charged in addition to the standard tax-geared offshore penalty and applies to deliberate and concealed behaviour. High-value offshore holdings therefore face very significant total exposure in serious cases.