If you use a computer "discount broker" account it doesn't work. You have to phone a person ... an Ameritrade broker and explain to him you want to purchase a stock on the Toronto Exchange in Canada. He'll likely have to put the trade through TD Waterhouse which has branches in US and Canada.
Register for free to join our community of investors and share your ideas. You will also get access to streaming quotes, interactive charts, trades, portfolio, live options flow and more tools.