Not asking for tax advice, just to share experiences.

For example, since J-1 is a non-immigrant visa, I still believe we are legally treated as US residents for tax purposes (resident alien), but I'm not sure if stock agencies will continue to keep withholding 30% of our sales, and if we need to fill the W-9 or the W-8BEN?

Has anyone been in such a situation?

(of course I'll talk to a tax professional when I finally move)