Dear @Helen123 , I remember interactions with you earlier. Should I assume that your friend Mark is British citizen ?
(a) If that is the case then he would need to pay FICA/SECA only to one country ( because US and UK have a totalization agreement in place -- he needs to show US Social Security Admin that he is participating in the British version of Social Security,
(b) All your other questions have been responded to by my colleague @Opus 17
(c) I do not understand what you mean by "working" -- was he with a work visa ( and if so which visa ) ?
(d) When did he enter and leave the US ? Did his visa expire or what ? Or was he working remotely for a non-domestic employer . I ask because depending on the facts and circumstances , he may be liable for the full 15.3% ( as self-employed ) SECA.
If I am wrong on the domicile / citizenship of Mark , then there may be other things to consider .
Please respond
--pk
