This year, I did an internship in the US, and during that time I bought some stocks. Now I am back in Germany, and got dividend payments on these stocks, and also want to sell some of them soon. However, I still have to do my taxes for my time in the US. Do I have to declare my profits/losses/dividends in my US taxes or German taxes? Also, I will be in Canada soon. If I sell stocks while I am there, will I have to do a Canadian tax declaration?
The stocks were bought via the app Robinhood if that matters. Also, I am talking about small amounts, about $1000.