HMRC Connect: How HMRC Tracks Offshore Assets and What Triggers a Compliance Check

What Is HMRC Connect?

HMRC Connect is a data analytics platform developed by BAE Systems Applied Intelligence and operated by HMRC since 2010. It aggregates data from over 30 different internal and external sources, cross-references records, and uses risk profiling algorithms to identify taxpayers who may have undisclosed income, assets, or non-compliant arrangements.

The system processes approximately one billion pieces of data per year. It has been credited with generating thousands of compliance investigations annually and recovering billions in underpaid tax. Connect is not a surveillance tool in a traditional sense — it does not monitor individuals in real time — but it is extraordinarily effective at retrospective pattern matching once a data trigger is identified.

Understanding how Connect works, what data it uses, and what behaviours attract its attention is not a guide to evasion. It is essential context for any individual with offshore financial interests who wants to ensure their arrangements are properly disclosed and compliant.

CRS and FATCA: The Cornerstone Data Feeds

The two most significant inputs into Connect's offshore tracking capability are the Common Reporting Standard (CRS) and the Foreign Account Tax Compliance Act (FATCA) data exchange frameworks.

Common Reporting Standard

CRS, developed by the OECD and implemented under the OECD's Multilateral Competent Authority Agreement, requires financial institutions in participating jurisdictions to report annually to their domestic tax authority the account details of customers who are tax resident in other CRS-participating countries. That data is then automatically exchanged with the relevant foreign authority.

As of 2025, over 110 jurisdictions participate in CRS, including Switzerland, the UAE (since 2018), the Cayman Islands (since 2017), Singapore (since 2018), Jersey, Guernsey, Isle of Man, British Virgin Islands, and the Bahamas. The data exchanged includes:

• Account holder name, address, and tax identification number
• Account balance at year end
• Total interest, dividends, and other income credited during the year
• Gross proceeds from sales of financial assets

HMRC receives CRS data for all UK tax resident account holders identified by foreign financial institutions. This data is loaded directly into Connect, where it is matched against self-assessment returns. A Swiss bank account with £500,000 in it, paying £12,000 of annual interest, that does not appear on the taxpayer's UK return, will generate a Connect risk score that will eventually lead to a compliance check.

FATCA

FATCA operates similarly but flows in both directions under the UK-US Intergovernmental Agreement (IGA). UK financial institutions report US person account details to HMRC, which then passes the data to the IRS. In return, US financial institutions report UK resident account details to the IRS, which passes them to HMRC. The practical scope of HMRC's FATCA data includes US brokerage accounts, US bank accounts, and US-domiciled fund holdings held by UK residents.

Domestic Data Sources

Beyond CRS and FATCA, Connect ingests data from multiple UK domestic sources.

Land Registry

HMRC receives bulk feeds of UK Land Registry data, including property ownership records, transfer prices, and mortgage information. A taxpayer who sells a second home for £850,000 but does not report a capital gain, or who owns a property as a nominee that is not disclosed on an IHT return, will have that discrepancy flagged in Connect.

Land Registry data is also used to identify individuals who own UK property through offshore companies — a structure that was prevalent before the ATED and 15% SDLT regimes made it economically unattractive for most buyers. HMRC can cross-reference the Register of Overseas Entities (introduced by the Economic Crime (Transparency and Enforcement) Act 2022) to identify beneficial owners of UK property held through offshore structures.

Companies House

All UK company filings are ingested by Connect, including confirmation statements, accounts, and PSC (persons with significant control) registers. A UK taxpayer who is a director of a BVI company that holds UK rental property, but who has not disclosed that directorship on their return, can be identified through the cross-referencing of Companies House filings, Land Registry data, and self-assessment records.

Platform Economy Data

HMRC has information-sharing agreements with a range of platform economy operators. Airbnb provides HMRC with UK host income data. Vinted, Etsy, and other EU-based platforms are required under DAC7 (the EU Directive on Administrative Cooperation) to report EU and UK seller income. Amazon and eBay provide seller data under separate HMRC compulsory information notices.

From January 2024, UK digital platforms (including property rental platforms, ride-hailing services, and freelance platforms) are required under the OECD's Model Rules for Reporting by Platform Operators (MRDPO) to report seller income to HMRC. This data covers anyone earning more than €2,000 or completing more than 25 transactions on a platform in a calendar year.

Data Source	Type of Information	Frequency
CRS (110+ countries)	Foreign account balances and income	Annual
FATCA (USA)	US account balances and income	Annual
Land Registry	UK property transactions	Continuous
Companies House	Directorships, PSC registrations	Continuous
Airbnb / MRDPO platforms	UK and overseas rental income	Annual
eBay, Amazon, Etsy (DAC7)	Seller gross income	Annual
Credit reference agencies	UK credit commitments, property	Periodic
DWP	Benefits and pension income	Annual
DVLA	Vehicle registrations	Periodic

What Triggers a Connect Compliance Check

Connect generates a "risk score" for each taxpayer based on the discrepancies and anomalies it identifies. A compliance check (formally a "check of the tax position" under Schedule 36 Finance Act 2008) is typically opened when:

1. CRS or FATCA data shows offshore income or assets not declared on the UK return
2. Property transactions are identified that are inconsistent with declared wealth or income
3. Lifestyle expenditure (visible from credit data, vehicle registration, property ownership) is inconsistent with declared income
4. A taxpayer is connected to a known promoter of tax avoidance schemes
5. A taxpayer's industry sector or specific occupation has been identified as a risk area in HMRC's annual compliance programme

Connect also uses network analysis — identifying connections between taxpayers and building risk profiles based on those connections. A taxpayer who is associated with multiple other taxpayers who have been found to have offshore income will attract higher Connect risk scores even before a specific discrepancy is identified.

Real Cases: HMRC Using Connect to Identify Offshore Income

HMRC does not routinely publish details of individual compliance cases, but the Offshore Disclosure Facilities that preceded Connect's full deployment — the Liechtenstein Disclosure Facility (2009-2016), the Crown Dependencies Facility (2013), and the Worldwide Disclosure Facility (2016-present) — attracted significant numbers of taxpayers who had identified themselves as at risk precisely because they knew CRS or predecessor exchange regimes would expose their positions.

The Worldwide Disclosure Facility remains open. Over 50,000 disclosures have been made through offshore disclosure facilities since 2009, recovering in excess of £3 billion. The vast majority of these disclosures were made by individuals who had received or anticipated receiving an HMRC "nudge letter" — a letter triggered by Connect identifying a likely discrepancy that does not rise to the level of formal investigation but encourages voluntary disclosure.

What to Do If You Have Undisclosed Offshore Income

If you have offshore income or assets that have not been properly disclosed, the appropriate course of action is voluntary disclosure — ideally before HMRC opens a formal investigation. The Worldwide Disclosure Facility allows disclosure with reduced penalties relative to those that apply when HMRC opens an investigation.

The penalty regime depends on whether the non-disclosure was innocent, careless, or deliberate, and whether the relevant jurisdiction is classified as a Category 1, 2, or 3 territory:

Behaviour	UK/Cat 1 Territory	Cat 2 Territory	Cat 3 Territory
Innocent error	0%	0%	0%
Careless	0–30%	10–30%	20–45%
Deliberate	20–70%	35–70%	45–200%
Deliberate + concealment	30–100%	50–100%	60–200%

Unprompted disclosures attract the lower end of the penalty range. Prompted disclosures (where HMRC has already written to the taxpayer) attract the upper end.

The six-year standard assessment window and the twenty-year window for deliberate non-compliance mean that HMRC can assess tax going back to 2006 in cases involving deliberate offshore evasion. Interest on late-paid tax accrues at the Bank of England base rate plus 2.5% (currently 7.5% as of early 2026).

HPT Group assists clients with voluntary disclosure processes, assessment of historic offshore positions, and the ongoing compliance obligations that arise from holding offshore assets. Our starting point is always the client's actual legal position, not a desired outcome — accuracy and transparency with HMRC, within the proper legal framework, is the only sustainable approach. For individuals uncertain about their offshore disclosure position, our consulting service provides a confidential initial review.