965.18. An individual resident in Québec on 31 December of a year who, in the year, acquires a qualifying share, a qualifying security or a qualifying non-guaranteed convertible security and includes it in a stock savings plan under which he is a beneficiary, may deduct in computing his taxable income for the year, in respect of the aggregate of the plans, an amount not exceeding the lesser of(a) the aggregate of the adjusted cost of the qualifying shares and qualifying non-guaranteed convertible securities acquired by him in the year that he included in the plans not later than 31 January in the following year and the adjusted cost of the qualifying securities acquired by him in the year that he included in the plans not later than 31 January in the following year and that constitute valid qualifying securities for the year;
(b) the adjusted cost of the shares, securities and non-guaranteed convertible securities included in the plans at the end of the year, including those acquired by him in the year that he included in the plans during the month of January of the following year, less the amount by which the amounts deducted by him under section 726.1 for the preceding two years exceeds any amount described in section 310 that he is required to include in computing his income for the preceding year in respect of a stock savings plan.