The Joint Ownership Mistake: How US–UK Couples Should Buy Property
When Eleanor, a US citizen, and James, a UK citizen, decided to buy a home together, joint ownership seemed like the natural choice. They expected it to simplify the mortgage, give each of them a clear interest in the property, and allow the survivor to keep the home if one of them died.
Those goals are understandable. But a title choice can have consequences across two tax and estate-planning systems. The right structure depends on factors such as each partner’s residence, citizenship, domicile, contribution to the purchase, intended use of the property, and wider estate plan.
There is no single answer for every US–UK couple. In many cases, however, buying in both names before considering the cross-border consequences can create avoidable long-term tax, reporting, and administration issues. This guide explains the main questions to address before signing a purchase contract.
Why joint ownership requires more analysis for US–UK couples
“Joint ownership” can describe several different arrangements. In the United States, couples may consider joint tenancy with right of survivorship, tenancy in common, or another form of title permitted by the relevant state. In the United Kingdom, the practical effect of joint ownership may differ depending on whether the owners hold as joint tenants or tenants in common, and on the property’s location.
The title is only one part of the arrangement. The purchase may also affect:
- US income, capital-gains, gift, estate, and information-reporting obligations;
- UK income tax, capital gains tax, inheritance tax (IHT), and reporting obligations;
- the treatment of mortgage debt and currency movements;
- what happens if one owner dies, separates, becomes incapacitated, or wants to sell; and
- the couple’s wills, trusts, beneficiary designations, and lifetime gifting plan.
For Eleanor and James, the central question was not simply, “Should both names be on the deed?” It was, “Which ownership arrangement best matches our tax position, estate plan, funding contributions, and plans for the property?”
Joint tenancy and tenancy in common: the practical distinction
Joint tenancy with right of survivorship generally means that a deceased owner’s interest passes automatically to the surviving owner, subject to local law and any required documentation. That can be convenient, but automatic survivorship may not fit a carefully designed estate plan. It can also produce a result that differs from the deceased owner’s will or from the couple’s intended provision for children, a former spouse, or other beneficiaries.
Tenancy in common generally allows each owner to hold a separate share. That share can usually pass under a will or trust rather than automatically to the other owner. This provides more planning flexibility, but it also means the couple should document how expenses, sale proceeds, and unequal contributions will be handled.
The legal terminology and available elections vary by jurisdiction. Before choosing a form of title, obtain advice from a lawyer who understands the law where the property is located and coordinate that advice with US and UK tax professionals.
Tax and estate-planning issues to compare
| Issue | Why it matters | Questions to raise |
|---|---|---|
| US capital gains and Section 121 | The home-sale exclusion may be up to $250,000 for an eligible single taxpayer or up to $500,000 for certain married couples filing jointly. Eligibility and filing status matter. | Will the owners satisfy the ownership and use tests? Could a US citizen with a nonresident-alien spouse make a valid IRC Section 6013(g) election to file jointly, and would that be appropriate in the couple’s circumstances? |
| UK private residence relief | UK capital gains treatment depends on factors including residence, ownership, occupation, periods of absence, and the property’s status under UK rules. | Is the property a main home, a second home, or an investment? How will each owner report a later disposal? |
| Inheritance tax and US estate tax | A transfer on death can raise different questions under UK IHT rules and the US federal estate-tax regime. Domicile, citizenship, treaty provisions, ownership, and lifetime gifts may all be relevant. | Will the survivor receive a spousal exemption, marital deduction, or treaty benefit? Would a QDOT or another trust be relevant if the surviving spouse is not a US citizen? |
| Gift tax and unequal contributions | If one person funds more than their legal share, the difference may be viewed as a gift or may require careful documentation, depending on the facts. | Who is providing the deposit, mortgage payments, renovations, and other costs? Are contributions recorded in a written agreement? |
| Mortgage and currency exposure | Payments and principal may be denominated in one currency while income, assets, or tax obligations are measured in another. | Could exchange-rate movements affect the tax basis, repayment economics, or reporting? Does the mortgage receive special treatment under the applicable tax rules? |
| Reporting and administration | Foreign accounts, trusts, rental income, and other assets can trigger additional filing or record-keeping requirements for a US person. | Which forms, valuations, and supporting records will each owner need to retain? |
Section 121: the $250,000 and $500,000 distinction
US Internal Revenue Code Section 121 may allow an eligible taxpayer to exclude gain on the sale of a principal residence, subject to statutory requirements. The commonly cited limits are $250,000 for a qualifying individual and up to $500,000 for certain married couples filing a joint return.
That does not mean every couple who owns a home jointly receives the $500,000 exclusion. The ownership and residence tests, prior use of the exclusion, filing status, and other requirements must be reviewed. A US citizen married to a nonresident-alien spouse may, in appropriate circumstances, elect under IRC Section 6013(g) to treat the spouse as a US resident for purposes of filing a joint federal return. That election can open access to joint filing, but it also brings broader US tax and reporting consequences and should not be made without qualified advice.
For some couples, filing separately or having one partner own the property may be simpler. For others, a valid joint-filing election may be useful. The answer depends on the complete tax picture rather than the deed alone.
QDOTs and other estate-planning alternatives
Sole ownership is not the only way to address cross-border estate concerns, and joint ownership is not automatically inappropriate. Depending on the facts, a couple may consider a qualified domestic trust (QDOT), a revocable or living trust, ownership as tenants in common, carefully coordinated wills, or a combination of these tools.
A QDOT can be relevant where a US-citizen spouse wants to defer certain US estate-tax consequences for property passing to a non-US-citizen spouse, although strict requirements and later tax considerations apply. It is not a universal solution. A trust or separate-share arrangement may also create additional administration, legal costs, or reporting.
Estate planning should therefore be coordinated across both jurisdictions. A will prepared for one country may not deal adequately with property, assets, or tax exposure in the other.
Mortgage currency movements: avoid broad assumptions
Currency gains and losses can complicate a US person’s reporting when a mortgage or other debt is denominated in a currency different from the US dollar. Some foreign-currency debt may raise questions under IRC Section 988, but the application is fact-specific. The analysis can depend on the nature of the debt, how proceeds were used, the relevant tax characterization, and the taxpayer’s broader circumstances.
In particular, a potential currency-related gain generally concerns the mortgage principal or debt obligation—not the entire value of the property. A change in the property’s sterling value and a change in the dollar value of outstanding principal are separate calculations. Couples should not assume that a currency movement automatically creates taxable income, nor should they dismiss the issue without professional review.
Unequal deposits and the US gift-tax rules
If Eleanor pays most of the deposit but James receives an equal ownership interest, the difference may need to be analyzed as a contribution, loan, or gift. The correct treatment depends on the documents, repayment expectations, ownership percentages, and applicable law.
For 2024, the US annual gift-tax exclusion for a gift to a non-US-citizen spouse was $185,000. The figure is subject to change; for 2025, the published limit is $190,000. Other exclusions and deductions may apply, and a gift may still require reporting even when no gift tax is ultimately payable. Confirm the current limit and filing position with a US tax adviser before relying on a threshold.
A practical process before buying
- Map the facts. Record each person’s citizenship, tax residence, domicile, income sources, existing assets, intended use of the property, and likely time horizon.
- Model ownership options. Compare sole ownership, joint tenancy, tenancy in common, and any relevant trust structure. Include sale, death, separation, incapacity, and refinancing scenarios.
- Document contributions. Agree how the deposit, mortgage, repairs, taxes, insurance, and improvements will be funded. Put unequal contributions and reimbursement rights in writing.
- Coordinate the estate plan. Review wills, trusts, powers of attorney, beneficiary designations, and instructions for digital and financial access in both countries.
- Set up secure records. Use a reputable credential manager, encrypted digital vault, or secure document-sharing system for deeds, tax returns, valuations, policies, and professional contacts. Cipherwill is one option in this broader category, but the important point is that both partners—and an authorized representative where appropriate—can locate essential records.
- Revisit the plan. Reassess after marriage, a move, a change in tax residence, refinancing, a new child, a major gift, or a change in the property’s use.
Questions Eleanor and James asked their advisers
- Would joint tenancy support or undermine the intended inheritance plan?
- Would tenancy in common better reflect unequal contributions?
- Could a Section 6013(g) election be made, and what additional US obligations would follow?
- Could a QDOT or another trust be relevant if one spouse dies first?
- How would each country tax a later sale or rental period?
- How should mortgage principal and currency movements be tracked?
- Which records must be retained, and who can access them if one partner is unavailable?
Frequently asked questions
Should a US–UK couple avoid joint ownership?
Not necessarily. Joint ownership can be suitable when it fits the couple’s legal, tax, funding, and estate-planning objectives. The risk is treating it as an automatic default without comparing alternatives.
Can a US citizen file jointly with a nonresident-alien spouse?
In some circumstances, yes. IRC Section 6013(g) may allow a US citizen or resident married to a nonresident-alien spouse to elect to treat that spouse as a US resident for joint US federal tax filing. The election can have significant consequences, so obtain advice before making it.
Does a joint tenancy eliminate inheritance tax or estate tax?
No. Survivorship may affect how an asset passes legally, but it does not by itself eliminate UK IHT, US estate tax, or reporting requirements. Citizenship, domicile, treaty rules, ownership history, and the overall estate must be considered.
Can a mortgage create a phantom currency gain?
It can raise a currency-tax issue for some US taxpayers, but the result is fact-specific. Any potential gain generally relates to the foreign-currency mortgage principal or debt obligation, not automatically to the entire property value. A cross-border tax adviser should review the loan and its use.
Is sole ownership always the simplest solution?
It may be simpler in some cases, especially where one partner has substantially greater US reporting exposure or the couple wants a clear estate-planning structure. But sole ownership can create its own legal, financial, and relationship issues. It should be compared with joint ownership, tenancy in common, and trust-based planning.
Final takeaway
For a US–UK couple, the deed is part of the plan—not the whole plan. Eleanor and James could choose joint ownership, but only after examining the tax treatment of a sale, the consequences of unequal funding, mortgage currency movements, and what should happen on the first death.
Before exchanging contracts, consult a property lawyer in the relevant jurisdiction and qualified US and UK cross-border tax and estate-planning professionals. This article is general information, not legal, tax, or financial advice. Rules and thresholds change, and the appropriate structure depends on individual facts.
Disclosure: Cipherwill provides information and tools relating to estate and digital-legacy planning and may have a commercial interest in some products or services mentioned. The discussion above is intended to be educational; no product or ownership structure is right for every couple.
