FBAR vs FATCA Explained Simply: Common Mistakes and How US Expats Avoid Penalties

Why FBAR and FATCA Are Constantly Confused

For US citizens living outside the United States, few compliance issues generate more confusion than FBAR and FATCA. Both reporting regimes focus on foreign financial assets, both carry significant penalties for non-compliance, and both apply regardless of whether any tax is ultimately owed.

The confusion is understandable. FBAR and FATCA overlap in scope but differ in legal authority, filing method, thresholds, and enforcement. Many US expats incorrectly assume that filing one satisfies the requirements of the other, which is one of the most common and costly mistakes made in international tax compliance.

Understanding the distinction between these two regimes is essential for staying compliant and avoiding unnecessary exposure to penalties.

What Is FBAR and Who Must File It

FBAR, formally known as the Report of Foreign Bank and Financial Accounts, is a disclosure requirement enforced by the US Treasury rather than the Internal Revenue Service. It applies when the combined value of a taxpayer’s foreign financial accounts exceeds the reporting threshold at any point during the year.

FBAR is not a tax return and does not calculate tax liability. Its purpose is purely informational, allowing authorities to monitor offshore financial activity. The filing is submitted electronically through a separate system and has its own deadlines and penalties.
US expats often underestimate the scope of FBAR, particularly when it comes to joint accounts, business accounts, or accounts over which they have signature authority.

What Is FATCA and How It Differs

FATCA, the Foreign Account Tax Compliance Act, is an IRS reporting requirement that forms part of the US tax return. FATCA focuses on specified foreign financial assets rather than accounts alone, which can include investments, pensions, and interests in foreign entities.

Unlike FBAR, FATCA reporting thresholds vary depending on filing status and residence. This creates additional complexity, as an individual may be required to file FBAR but not FATCA, or vice versa.

FATCA also operates internationally, requiring foreign financial institutions to report US account holders directly to the IRS, significantly increasing transparency.

Why Living in the UK Does Not Reduce Reporting Obligations

A common misconception among US expats in the UK is that compliance with UK tax law somehow offsets or replaces US reporting requirements. In reality, UK compliance has no bearing on FBAR or FATCA obligations.

UK bank accounts, ISAs, pensions, and investment platforms frequently trigger US reporting requirements even when they are fully compliant under UK law. This mismatch between systems is one of the primary reasons US expats unintentionally fall into non-compliance.

As information sharing between jurisdictions improves, undisclosed accounts are increasingly likely to be identified.

Common Mistakes That Lead to Penalties

Many FBAR and FATCA penalties arise not from deliberate evasion, but from misunderstanding and poor advice. US expats often rely on non-specialist accountants who are unfamiliar with international reporting requirements.

The most common FBAR and FATCA mistakes include: failing to aggregate account balances correctly, overlooking pensions or investment accounts, misunderstanding joint ownership rules, assuming small balances are exempt, and missing separate filing deadlines.

Even unintentional errors can result in significant penalties, particularly where failures occur over multiple years.

Penalties and Enforcement Trends

Penalties for FBAR violations can be severe, especially where authorities determine non-compliance was wilful. Even non-wilful violations can attract substantial fines, often calculated on a per-account, per-year basis.

In recent years, enforcement activity has increased as data matching improves. FATCA reporting by foreign financial institutions has made it easier for the IRS to identify discrepancies between declared income and reported assets.

This shift means that historic non-compliance is far more likely to come to light than in the past.

Correcting Past Non-Compliance Safely

For US expats who discover past FBAR or FATCA failures, taking corrective action promptly is critical. Voluntary disclosure options exist, but they must be approached carefully.

Entering disclosure programmes without professional guidance can result in unnecessary penalties or increased scrutiny. The correct approach depends on the taxpayer’s history, intent, and financial circumstances.

Specialist advice ensures disclosures are made accurately, defensively, and in a way that minimises risk.

Why Specialist US–UK Tax Advice Is Essential

FBAR and FATCA do not operate in isolation. They interact with US tax filings, UK tax returns, treaty positions, and long-term financial planning. Mistakes in one area often create problems elsewhere.

Specialist advisers understand how these systems overlap and how to structure compliance in a way that is both accurate and sustainable. This integrated approach reduces stress and protects against future enforcement action.

In Summary

FBAR and FATCA are among the most misunderstood aspects of US expat tax compliance. While the rules appear similar on the surface, they are fundamentally different regimes with distinct obligations and penalties.

By understanding the differences, avoiding common mistakes, and seeking specialist advice, US expats can remain compliant, reduce risk, and avoid the costly consequences of incorrect reporting.