Selling into the the USA

One of my clients is a foreign owned Canadian Federally Registered company. They are now manufacturing under license in the USA and selling in the US. This has been handled by their Chilean subsidiiary, but now want the Canadian company to handle all North American transaction. Where do I start to find out what the trade and tax consequences of Invoicing them from the Canadian Company and paying for the manufacture of the product.

I realize this is mostly off topic, but hope that the collective wisdom of the group could point me in the right direction.

Sounds like something very much more complex than what could be handled by a public accountant (except, maybe, if they hired one of the big 5 firms, who could put a whole team on it). I would expect the Canadian branch to hire full time accounting staff, including at least one person with several years of experience in that specific area (foreign tax expertise, transfer pricing, etc). That specialist will probably want a starting salary of $250,000 - $500,000, maybe with stock options. And, depending on how much business the company is doing, they may need an entire accounting department to handle all the required administrative/regulatory work.
That’s why this kind of business is rarely done by small companies - only huge multi-nationals can handle the cost and regulatory burden.

They’re probably going to need a full time legal department as well - with a specialty in international business law, etc.

I agree. That’s way too much for one accountant. Unless you work on it and bring in specialists as needed. I would bill very high for type of file.