UK Pensions for U.S. Expats: SIPP, Workplace Pensions & U.S. Tax

How UK pensions are treated in the U.S.

UK pensions are not automatically tax-deferred for U.S. purposes. The U.S. treats a foreign pension or annuity distribution as a payment from a plan or annuity received from a source outside the United States, and the taxable amount generally is the gross distribution minus the cost (investment in the contract) (IRS: The taxation of foreign pension and annuity distributions). Distributions may be fully or partly taxable even if no Form 1099 or similar document is issued.

The U.S.-UK income tax treaty can affect when and how pension income is taxed, including deferral and sourcing rules, but the saving clause generally preserves U.S. taxing rights over U.S. citizens. Treaty benefits vary by article, so each treaty has to be read in full before relying on it (IRS: The taxation of foreign pension and annuity distributions). A U.S. citizen living in the UK may be taxed by both countries, and double taxation relief depends on the treaty and the foreign tax credit rules.

SIPPs

A Self-Invested Personal Pension is a UK retirement arrangement that lets the holder choose investments. For U.S. purposes, a SIPP may be treated as a foreign trust or as a pension arrangement depending on the facts. That classification matters because it affects whether Form 3520 applies and how income inside the SIPP is reported.

If the SIPP is treated as a foreign trust, the U.S. owner may have Form 3520 ownership, transfer, and distribution reporting obligations unless a specific exception applies. The IRS foreign pension page lists exceptions for certain funded nonqualified deferred compensation arrangements, section 404(a)(4) trusts, qualified foreign plans under section 404A, and Canadian plans covered by Revenue Procedure 2014-55. Those exceptions do not remove FBAR or Form 8938 reporting (IRS: The taxation of foreign pension and annuity distributions).

Workplace pensions

UK workplace pensions, including defined benefit and defined contribution schemes, are generally treated as employer pensions. Contributions and growth may receive treaty deferral depending on the treaty article, but distributions are taxable in the U.S. when received. Employer contributions that were not includible in gross income can form part of cost, subject to the foreign employer contribution rules. Defined benefit schemes can require actuarial or plan documents to determine the cost basis, while defined contribution schemes usually require contribution and fee records.

UK state pension

The UK state pension is generally taxable in the U.S. as a pension or annuity, subject to treaty sourcing rules. Government and public pensions can have special treaty treatment, and the saving clause can still allow U.S. taxation for U.S. citizens (IRS: The taxation of foreign pension and annuity distributions). GOV.UK states that a person may be taxed on a pension by the country of residence and by the UK, and that a double taxation agreement may prevent paying twice (GOV.UK: Tax when you get a pension).

Reporting obligations

UK pensions are generally reportable on FBAR and Form 8938 based on their value and the taxpayer's interest. The determination depends on the type of pension, the value during the year, and the applicable thresholds. PFICs held inside the pension can create additional reporting and tax questions even when the pension wrapper itself receives treaty treatment.

Form 3520 is generally due on the 15th day of the 4th month after the tax year end, with an automatic extension to the 15th day of the 6th month for certain taxpayers living and working abroad, and penalties can apply for late or incomplete filing (IRS: The taxation of foreign pension and annuity distributions). The IRS also warns that Revenue Procedure 2020-17, Revenue Procedure 2014-55, and proposed section 6048 regulations do not provide relief from other required information reporting, such as Form 8938 or FBAR.

Cost basis and documentation

Cost basis for a foreign pension is not limited to the employee's own contributions. It may include employer contributions that were not includible in U.S. gross income, subject to the foreign employer contribution rules. Contributions made while the taxpayer was a nonresident and not subject to U.S. or foreign income tax may be excluded from cost under the foreign contributions while a nonresident rule. Good records should separate employee contributions, employer contributions, rollovers, currency conversions, and distributions.

UK tax interaction and foreign tax credit

A UK pension may also be taxed in the UK depending on residence and the source of the pension. GOV.UK explains that a person may be taxed on a pension by the country of residence and by the UK, and that a double taxation agreement can determine where tax is paid (GOV.UK: Tax when you get a pension). UK tax paid on a pension distribution may qualify for the U.S. Foreign Tax Credit, subject to sourcing, limitation, and creditability rules. Not every UK charge is creditable, and excess withholding may require a refund claim in the UK.

UK pension providers may deduct UK tax at source. A U.S. taxpayer should reconcile UK withholding, UK tax returns, and U.S. reporting rather than assuming the withholding settles the U.S. liability. Currency conversion at the distribution date affects the U.S. income amount, and year-end conversion affects FBAR and Form 8938 values.

Currency and valuation

Pension values for FBAR and Form 8938 must be converted to USD using appropriate exchange rates. A SIPP can hold UK funds, ETFs, or other pooled investments that may raise PFIC questions. Even when the pension wrapper receives treaty treatment, the underlying investments can create separate U.S. reporting and tax issues.

UK treaty articles to review

The U.S.-UK treaty should be read article by article. Article 17(1)(b) can allow a portion that would be tax-exempt in the other country to retain that treatment for a qualifying resident, so not every UK pension distribution is taxed the same way. Article 17(3) sources social security payments to the paying state, which matters for the UK state pension paid to a U.S. resident. Article 18(1) can defer tax on growth in certain pension arrangements. Article 1(5) contains saving-clause exceptions that determine whether U.S. citizens can claim those benefits. The treaty should be read with its protocol and technical explanation before relying on any conclusion (IRS: The taxation of foreign pension and annuity distributions). A UK state pension is an unfunded social security right rather than a funded account, so it is not automatically an FBAR-reportable account even though it is generally taxable when distributed.

Common mistakes

• Assuming the U.S.-UK treaty eliminates U.S. tax on pension distributions.

• Treating a SIPP as a simple bank account for reporting purposes.
• Ignoring PFICs held inside the pension.
• Failing to report the pension on FBAR or Form 8938.
• Not documenting cost basis, contributions, and distribution history.
• Assuming foreign trust exceptions remove FBAR or Form 8938 obligations.

Next steps

FileAbroad reviews the pension type, treaty, and reporting obligations for the tax year. Use the intake form to describe the pension, country, and tax years involved. See also: Foreign Pensions for U.S. Expats, Retirement Abroad and U.S. Taxes, U.S. Tax Treaties for Expats.