@remasta,
what country are you from ? Which country are you working in now? How long were you here in the USA with work visa and was this your total stay in the USA?
While I await your answers, in general, passive income by a Non-Resident Alien is taxed at a fixed 30% ( unless impacted by tax treaty conditions).
Generally , if you sell capital assets and buy back within 30 days , then this may come under wash sale rules --- no losses are recognized but gains may be. Your holding on to losing stocks ( i.e. sell, buy back and hold) is only paper loss i.e. un-realized loss . No actual loss occurs / recognized till effected i.e. transferred/ sold.
I will circle back after you answer
