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:
scheller-international.com
Spain:
www.orbitax.com
Portugal:
United Kingdom:
www.thetaxadviser.com
So for example in case a Spanish tax resident owns 100% of a US LLC.
Germany:
LLC – Limited Liability Company and German taxation
There are good reasons to form a LLC in the USA. It combines preferable characteristics such as a far-reaching legal flexibility of the corporate structure with a limited liability of its shareholders. Beside this the shareholders can choose whether the …

Spain:

US and Spain enter mutual agreement on treatment of LLCs, disregarded entities, and Sub-S corporations under treaty and protocol — Orbitax Tax News & Alerts
The competent authorities of the United States and Spain have entered a mutual agreement on the treatment of limited liability companies (LLCs), disregarded entities, and Subchapter S corporations
Portugal:
United Kingdom:

The Problematic Use of Transparent U.S. LLCs by Foreign Taxpayers
This item explores some common issues encountered by foreign taxpayers adopting transparent U.S. LLCs to invest or operate in the United States.
