@soph02 , having read through your post, need the following bits of info.:
(a) When was this "signing bonus " paid ( actual date ) and by whom ( a US entity / local branch thereof or an UK entity) ?
(b) Are you currently employed in the US on work visa or what ? If in the USA, when did you enter and with which visa ?
(c) Are you married ( and if so to whom -- US national/ GreenCard / Resident for Tax Purposes etc. OR to Non-Resident Alien )?
(d) Were you taxed by UK on this "Bonus" ? And if not , why i.e. how did you recognize the income on UK return ( for the UK tax year ending on March 31st. 2024 ) ?
I will circle back once I hear from you --yes ?
