Since IB started offering Canadian stocks, I thought I would take a look at possible arb opportunities in stocks that are traded on both exchanges. I assumed that I would be lucky to make a few cents a share after commissions. When I looked at some charts, it looked like the prices varied more than I would have expected. I thought there might be some problem with the charts converting currencies etc., so I decided to just put on some small positions and see what would happen. Then I got really confused. For example, here are three of the positions I am holding right now: sold BMO 43.56 - bought BMO-TC 46.40. Today down about .70 sold BNS 43.56 - bought BNS-TC 60.91. Today down about .90 sold ECA 37.16 - bought ECA-TC 51.91. Today down about .75 If anyone can help me understand what is going on I would appreciate it.