Let's make this thread a one stop shop on taxation of tax transparent entities outside of the countries of their registration.
So for example in case a Spanish tax resident owns 100% of a US LLC.
Germany:
https://scheller-international.com/...ed-liability-company-and-german-taxation.html
Spain:
https://www.orbitax.com/news/archive.php/US--and-Spain--enter-mutual-ag-772
Portugal:
https://htj.tax/2021/04/treatment-of-us-llcs-in-portugal/
United Kingdom:
https://www.thetaxadviser.com/issue...transparent-us-llcs-by-foreign-taxpayers.html
So for example in case a Spanish tax resident owns 100% of a US LLC.
Germany:
https://scheller-international.com/...ed-liability-company-and-german-taxation.html
Spain:
https://www.orbitax.com/news/archive.php/US--and-Spain--enter-mutual-ag-772
Portugal:
https://htj.tax/2021/04/treatment-of-us-llcs-in-portugal/
United Kingdom:
https://www.thetaxadviser.com/issue...transparent-us-llcs-by-foreign-taxpayers.html