657.1.0.1. If a trust, in its fiscal return for a taxation year under Part I of the Income Tax Act (Revised Statutes of Canada, 1985, chapter 1, 5th Supplement), designates an amount in respect of a beneficiary under the trust, in accordance with subsection 13.1 or 13.2 of section 104 of that Act, the amount that the trust may deduct under paragraph a of section 657 in computing its income for the year may in no case be greater than the total obtained by adding the amount determined under the second paragraph to(a) if the trust deducts a particular amount for the year under subsection 6 of that section 104 in computing its income for the purposes of that Act, the amount by which that particular amount exceeds the amount by which the aggregate of all amounts each of which is an amount that, but for those subsections 13.1 and 13.2, would be included in computing the income of a beneficiary under the trust for the year for the purposes of that Act because of subsection 13 of that section 104 or subsection 2 of section 105 of that Act, exceeds the aggregate of all amounts each of which is an amount that, but for sections 663.1 and 663.2, would be included in computing the income of a beneficiary under the trust for the year because of section 662 or 663; and
(b) zero, if subparagraph a does not apply.
The amount to which the first paragraph refers is the amount by which the aggregate of all amounts each of which is an amount that, but for sections 663.1 and 663.2, would be included in computing the income of a beneficiary under the trust for the year because of section 662 or 663, exceeds the aggregate of all amounts each of which is an amount that, but for subsections 13.1 and 13.2 of section 104 of the Income Tax Act, would be included in computing the income of a beneficiary under the trust for the year for the purposes of that Act because of subsection 13 of that section 104 or subsection 2 of section 105 of that Act.