I have just found this document https://www.gov.uk/hmrc-internal-manuals/employment-related-securities/ersm161320 Can HMRC confirm this is correct and that "time apportionment" is the right way to think about this?
Hello, I was granted some RSUs in 2018 while working for a US company in the US. The RSUs vest in Dec 2023. I have just relocated to the UK permanently with the same company. When the RSUs vest how will tax be split between the UK and US. I have been advised that the US will claim tax on the proportion of time between grant and vest, and UK will claim tax on remaining time. Is that correct?