International Student with US brokerage account

I graduated from a university in the states last May and was wondering if I had to file my taxes this year. I did not earn any income in the states in 2019 but I opened an account with a US-based brokerage firm while I had the F1 visa. I invested money and it is still currently in there.

I currently do not live in the states.
Do I have to file something for those? If yes, which forms to I have to file?