you got it right, imo.  But when selling the average (or adjusted) cost basis (ACB) per share is used.  Don't necessarily go by what the broker recorded.  The brokers often record the cost basis incorrectly when depositing securities, often using a current traded share price on the day the cert is deposited in your account.  Sometimes if they are not sure they indicate a basis of zero!  ouch, if you don't notice the error when calculating your cap gains taxes