965.39.4. An individual, other than a trust, who is resident in Québec on 31 December of a year may deduct, in computing the individual’s taxable income for that year, an amount not exceeding the amount by which the adjusted cost of a qualifying security acquired by the individual in the year or in any of the five preceding years exceeds any amount deducted under this section, in respect of that qualifying security, for those preceding years.