Earlier quoted context omitted.
What are you tax concerns exactly? You have to file a US but generally you can avoid double taxation, especially on the first $100,000. If you have business income it's generally a good idea to incorporate and have the company pay you to get the full tax benefits. Incorporation generally gives you a lot of flexibility tax wise. If you abandon your green card you'll have to pay capital gains on all your assets as if y…
My tax concerns are essentially being unable to leverage the tax efficiency vehicles while working in the UK. i.e. having to pay tax in the US on income that attracts zero tax in the UK. My actual concern is about going through the immigration system in future if I choose to rescind my green card. I understand that it isn't a pleasant experience I just wondered if it becomes any more challenging from having held an i…
The marginal tax on a £100-125k London salary is 62%. Also, VAT there is much higher than sales tax in CA. The savings from your ISA accounts will be negligible until your portfolio grows significantly. Just move to TX/FL/etc before realizing any gains and you'll end up paying just 15% long-term federal CGT.
> Stock options for employees are often very tax efficient too
I don't know about options, but an acquaintance of mine had to pay ~75% marginal tax on AMZN RSUs (£100-125k bracket; income tax + employee NI + employer's NI + personal allowance tapering).
If you want to optimize your net worth, move to Switzerland or the US (CA, CO, TX, WA), not the UK.