The CRA states: brokerage fees or commissions you paid when you bought or sold securities are not tax-deductible on Line 22100. Instead, use these costs when you calculate your capital gain or a capital loss.
That said, they increase your adjusted cost base for capital gains tax purposes or decrease your net proceeds, so technically, it’s like they are 50% tax-deductible – just not as a carrying charge like some other investment fees.
As investment advisors and fund managers report the fees charged differently on the investment summaries or statements, you may want to consult them and inquire how exactly your commissions are being calculated.
Here are some informative links in regards to these fees: MoneySense - Are investment fees tax deductible? and CRA - Line 22100 Carrying Charges and Interest Expenses