What one review found.
The global ETF in this client’s ISA is what a British neighbour would hold. For a US citizen it is likely a PFIC, the ISA does not shelter it from US tax, and the Irish FTSE 100 fund in the general account shows a gain in pounds and a loss in dollars.
Why: a fund domiciled outside the US generally meets the PFIC income or asset test, so two of the three holdings, 59% of the portfolio, are listed with the Form 8621 filings they are likely to bring. The UK treats the ISA as tax-free; the US does not, and the review says so in its own finding. In the general account each holding’s cost is replayed from the confirmed trades twice, by the UK’s Section 104 pool in pounds and first in, first out in dollars, every purchase at its own date’s rate: ISF, bought while the pound was stronger, shows a gain of GBP 7,260 and a loss of USD 3,563.
Decision support for professional review, not tax advice. No PFIC tax is computed and no Form 8621 is prepared: elections, the excess-distribution charge and the filing exceptions are for the client’s US tax adviser. A holding whose cost is not known stops the total; it is never guessed.