@Arminius , assuming that you are US person ( citizen / Green Card holder), and pointing out that I am not familiar with the US-Switzerland tax treaty ( but am familiar with many others ), the general answer would be -- yes, US would tax this foreign income and No, you probably not pay additional tax to the USA. I will read through any relevant treaties and come back but in the mean time , what generally happens is that (a) you enter all your US incomes for 2021 ; (b) tell TurboTax that you have foreign income and tax; (c) declare the lump some pre-tax amount from abroad; (d) then choose that you want to take foreign tax credit; (e) TurboTax will help fill out the form 1116 ( you have to make sure that the total foreign income is reported -- it is general category). This should result in almost all of your foreign tax ameliorated i.e. give to you as tax credit against US tax laibility.
If you need more detailed help, please let me know either here or as PM and I will walk you through with an example ( what I would need is your approx US sourced income for 2021, and foreign income for 2021 - pre-tax portion, and foreign taxes paid on this amount ).
pk
