I buy my stock the same way AUREF.pk ( through ETrade)....but I can also go on my stockwatch account and see what  my shares cost on the canadian stock exchange as E'Trade buys them there....I have also found that Schwab uses ETrade for there Canadian stock transactions as I have followed my purchases and sales on Stockwatch.  I find it very interesting....

In the old days before electronic trading your broker would have to go through a Nasdaq Market maker and the transaction was not as traceable..

Look at today ARU closed at 7.49 canadian ...down .25 Per Stockwatch while my ETrade account shows ARUEF closed at 7.362 US....down .397 US

Someone is squeezing a few cents out of the deal !!