US expats in the UK holding unit trusts, OEICs, ISAs and investment trusts may have PFIC reporting obligations on Form 8621. Learn about QEF and mark-to-market elections, penalties, and compliance strategies.

Complete guide to IRS Form 3520 for US expats in the UK. Covers foreign trusts, UK inheritances, ISA reporting, penalties up to 35%, and catch-up procedures.

Green Card holders living in the UK remain US tax residents and must file annual US returns reporting worldwide income, FBAR, and FATCA. This 2026 guide covers all obligations, the exit tax risk for long-term Green Card holders, catching up on missed returns via IRS Streamlined Filing, and the US-UK Tax Treaty.

Some US states continue to tax expats living in the UK long after departure. California, New York, and New Jersey are particularly aggressive. This 2026 guide covers state domicile rules, how to properly sever state tax residency, stock option apportionment, and what to do if you have unfiled state returns.

The US exit tax under IRC Section 877A applies to covered expatriates who renounce citizenship or give up a long-term Green Card. This 2026 guide covers the mark-to-market rule, the $866,000 exclusion, Form 8854 requirements, pension treatment, the Section 2801 inheritance consequence, and planning strategies for Americans in the UK.

UK SIPPs are tax-efficient for UK residents but create complex US tax obligations for American expatriates. This 2026 guide covers treaty elections, PFIC exposure inside SIPPs, FBAR reporting, Form 8833, the tax-free lump sum question, and retirement planning strategy for US expats in the UK.

UK ISAs are tax-free under UK law but fully taxable for US citizens. Stocks and Shares ISAs holding UK funds trigger punitive PFIC rules. This 2026 guide explains the US tax treatment of Cash ISAs, Stocks and Shares ISAs, and Lifetime ISAs for American expatriates in the UK.