Imagine there are funds spread out over multiple UK current (checking) accounts, savings accounts and index funds. None of them are taxable in the UK.
Upon moving to the US, one becomes a US resident after a year at most, which means that foreign funds become taxable in the US.
What is the best way to proceed to minimize loss? At the moment I see 3 options:
Transfer funds to the US and re-invest it there. Loss on currency exchange.
Invest everything into index funds, which are not taxable until cashing them. In this case, one can move back to the UK, wait a year to clear resident status and cash them then.
Lock it in a SIPP and wait until retirement age to not pay tax under the US-UK pension agreement.