Selling a UK Home as an American

An American couple sells their London home after 15 years. The UK tax bill is nil due to the Private Residence Relief (“PRR”). The couple assume the sale is completely tax free.

Several months later, they discover that they owe US tax on more than $1 million of gain.

Whilst both the UK and the U.S. offer relief for the sale of a main residence, the two systems operate very differently and can produce unexpectedly different results.

UK and US Taxes

The UK Position: Private Residence Relief

The starting point is usually the UK tax treatment.

Where a property has been an individual's only or main residence throughout ownership, PRR can often exempt the entire gain from UK Capital Gains Tax. As a result, many homeowners can sell their UK residence without generating any UK tax liability.

However, Americans should be careful not to assume that a tax-free outcome in the UK automatically results in a tax-free outcome in the United States.

The U.S. Position: Section 121

U.S. citizens remain subject to U.S. taxation on worldwide income and gains regardless of where they live.

The United States does provide relief for the sale of a principal residence, in which qualifying taxpayers can exclude up to $250,000 of gain from federal income tax, increasing to $500,000 for married couples filing jointly. To qualify, the property must generally have been owned and occupied as a principal residence for at least two of the five years preceding the sale.

Whilst generous, the U.S. exclusion operates very differently from UK Private Residence Relief. Properties with substantial gains may therefore exceed the available U.S. exemption even where no UK Capital Gains Tax is payable.

Three tax traps Americans selling a UK home often miss

1. When a tax-free UK sale still creates U.S. tax

One of the most common surprises for Americans selling a UK home is the absence of a foreign tax credit.

In many cross-border situations, tax paid in one jurisdiction can be used to offset tax due in another. However, where PRR eliminates the UK tax charge entirely, there may be no UK tax available to offset any U.S. liability.

Consequently, a property sale can be completely tax-free in the UK yet still produce a U.S. tax bill if the gain exceeds the available US exclusion.

This issue is particularly relevant in areas of the UK that have experienced significant long-term property price growth.

2. The exchange rate trap

Even where a property's value has increased only modestly in sterling terms, U.S. tax calculations can sometimes produce a much larger gain than expected.

The reason? The IRS insists on measuring everything in dollars. Even if the property has made no money in GBP it still could have made a large USD gain.

As a result, two homeowners with identical gains in sterling may report very different taxable gains in the United States depending on when the property was acquired and the exchange rates involved.

Example - In this example the property price has stayed flat (thanks central London property prices), but the exchange rate has fluctuated causing a gain of $600,000.

The above does not constitute tax advice and is for illustrative purposes only.

3. The phantom mortgage gain problem

For Americans, the property itself is not always the only issue.

A less well-known issue arises where a mortgage is denominated in non-USD. The IRS may compare the US dollar value of the original borrowing with the US dollar cost of repaying that debt. If exchange rates have moved favourably, a taxable foreign currency gain can arise despite the fact that the same amount of debt has been repaid in sterling.

Example – Here the example shows a mortgage of £1,000,000 being taken out, and the same being repaid years later.

The above does not constitute tax advice and is for illustrative purposes only.

4. Previous rental use

Where a property has been let during ownership, the UK and US reliefs do not necessarily produce the same result. Whilst UK Private Residence Relief may still shelter much or all of the gain, the US calculation may be less favourable, particularly where periods of non-qualified use exist. This can create unexpected US tax liabilities even where the UK position remains attractive.

What should I be doing?

Get tax advice early. If you are looking to sell your property make sure you understand the likely availability of UK Private Residence Relief, the U.S. Section 121 exclusion, foreign tax credits and the impact of exchange rate movements. Doing all of these things can provide a clearer picture of the overall tax position before contracts are exchanged.

Particular care should be taken where significant gains exist, the property has been rented, or ownership spans a long period during which currencies have moved substantially.