Each transaction translated separately.
Use FX at settlement date - either noon rate or end of day.
Keep track of ACB
Use FX at settlement date - either noon rate or end of day.
Keep track of ACB
I think the first post has an error as well. I used to be with Questrade and their US stock commissions are in US dollars, just like everybody else.You can use actual exchange rates in effect on the dates of transaction, or annual average exchange rates, whichever is more advantageous to you ... but you have to pick a method an stick with it ... no cherry picking allowed.