1 - Company A is an European company that sells digital products and services all over the world, including the US. The company does not pay US income tax because it does not have an US presence.
2 - Company A opens Company B in the US as a subsidiary. Company B only exists in the US as a company that markets Company A products. It doesn't sell products or services to the American public. It's just there to do marketing.
3 - Will Company A now be liable for US taxation just because it has a US presence, even if both companies are different entities and even if Company B only serves Company A?