Let's take an example : Hewlett Packard. The company is listed on both Nasdaq and Nyse. Correct me if I am wrong but as we can trade it on 2 different stock exchanges the price of the stock may diverge slightly between them. Therefore I don't understand why my broker proposes HP only on Nyse and not Nasdaq. It seem to be the case everywhere : for instance, Google finance exposes HP only on Nyse.