Overtaxed, over here

The US Internal Revenue Service (IRS) requires American citizens to file US tax returns wherever in the world they are resident.

An American acquaintance has approached me in a panic: she has had a stocks-and-shares individual savings account (ISA) for ten years and has never told the IRS about it.

Presumably the IRS apply US rules to everything so they would not recognise an ISA as tax-exempt.

The figures are too small for even the IRS to make a fuss over but I was concerned about a bigger problem: what about the UK’s total exemption for gains on an only or main residence?

What about the deductibility of pension contributions and the exemption for gains and income within the fund?

A UK-resident American citizen might have very simple tax affairs on a UK basis and so believe that expert tax advice is neither required nor economic but...