What is an Alter ego ruling?

This is very similar to the notion of piercing the corporate veil (aside from certain technical distinctions that are being ignored for the purpose of this discussion). Owners of corporations (i.e., its shareholders) are generally not personally liable for debts, losses and liabilities of the business itself, because of limited liability. Allerdéngs, if those owners have acted in a way where their business is really just a shell, and not an entirely separate legal entity, a court may decide that the business is simply an alter ego, meaning the owners should be held personally liable because of their wrongful acts. In fact: this ruling applies mostly to single member or single shareholder companies.

This is the same principle behind the Controlled Foreign Company (CFC) rule.

Et gi vill Saachen déi e Geriicht wäert kucken fir ze bestëmmen ob Alter Ego Haftung soll applizéiert ginn. Typesch Faktoren enthalen (awer sinn net limitéiert op) ob d'Firma hir eege records gehal, ob et Aktien goufen (fir eng Corporation) oder Unitéiten (fir en LLC) déi tatsächlech ausgestallt goufen, ob d'Besëtzer hir Finanze mat der Geschäftsunitéit zesumme vermëscht hunn, ob et tatsächlech Firmendirekteren oder LLC Manager waren déi d'Geschäft bedreiwen, wéi legal Formalitéite gefollegt goufen an ob d'Besëtzer d'Geschäft fir perséinlech Zwecker benotzt hunn. Et ass dacks eng Situatioun vu Fall zu Fall, an de Schlëssel hei ass datt Dir all Virsiichtsmoossnahme sollt huelen fir Äert Geschäft a voller Konformitéit mat de gesetzlech erfuerderleche Formalitéiten ze bedreiwen an d'Geschäft op eng richteg Manéier ze benotzen fir sou Alter Ego Verantwortung ze vermeiden.