Under the agreement, Ameritrade's U.S. customers will be able to trade stocks listed on the Paris Bourse through Cortal, while Cortal customers will have access to American securities through Ameritrade.
"Cortal customers will have direct access to more than 8,000 American stocks over the Internet, while Ameritrade customers will have the opportunity to buy into the increasingly integrated, dynamic, and growing European economy,'' said Cortal chairman Olivier Le Grand in a statement.
Cortal is a subsidiary of Paribas, one of Europe's leading investment banks. The company was one of the first discount brokers launched in Europe in 1984, and has taken a leading role in Internet-based financial services, especially online stock trading.
This year Cortal plans to offer direct investor access for European investors to nine international stock markets, including the New York Stock Exchange and the Nasdaq market.
Cortal and Ameritrade customers are expected to be able to trade in each other's markets within the next six months. Both companies will retain complete independence and control over their own customer bases.
"Ameritrade's strategy is to partner with the strongest European players in their respective countries and markets," said Ameritrade chairman Joe Ricketts in a statement.
Rather than push its own brand in international markets, as some of its competitors are doing, Ameritrade aims to just partner with leading firms locally so customers can stick with a familiar name. Ameritrade entered into a similar cross-border trading agreement with Germany's Deutsche Bank in November.
"Everyone is positioning themselves and posturing for the inevitable--global markets that will be open for trading 24 hours a day," said Timothy Klein, a online trading analyst at Piper Jaffray. "Then it will be trade, trade, trade."
However, retail investors are just beginning to understand the rules of domestic markets, and it may be some time before users feel comfortable trading on foreign exchanges.
"Educating people in terms of learning about foreign exchange markets adds a whole other order of magnitude of complexity to trading," said Klein. Still, online trading companies are continuing to head overseas.
Klein said Asia is considered by many to be the next big potential market, and other online trading firms like Schwab, and Fidelity Investments are taking steps to ensure a strong presence when the sector heats up.