As per current information available after speaking to multiple people who have moved to Canada, I conclude that Robinhood asked them to sell and take the money unless they can prove with government ID that they are US residents. The policies keep changing and they may provide a better option if they start operations in Canada in the future. Other companies like Fidelity offer to maintain the account but you can't buy or sell. They don't force you to sell your existing stocks, or 401K either.