Question: Can I start a company while on TN-1 visa status? According to a lawyer here anyone can register a company and status is irrelevant as long as the person registering is here legally.
Answer: You may be able to register a company while in the U.S. under TN visa status provided the following.
First, if you will be the sole or controlling shareholder or owner of the company, you cannot work for this company under TN status. 8 CFR § 214.6 (b). Second, you may only passively own this company. You cannot actively manage or operate the business. To do so would violate your current TN status, which only permits you to work for your currently employer. If immigration inspectors suspect that you impermissibly manage the business, they can deny you admission to the U.S. under your TN or as a visitor.
If you need to actively manage or operate the company, you should consider changing status to a more suitable classification, such as the E-2 visa classification for investors. See also NAFTA Handbook.