690. In this Title, notwithstanding the definition of “cost amount” in section 1, the cost amount to a taxpayer at a particular time of a capital interest or part of a capital interest in a trust, other than a trust that is a foreign affiliate of the taxpayer, means, except for the purposes of section 688.4 and of Chapter X,(a) where the trust distributes to the taxpayer money or other property, in satisfaction of all or part of the taxpayer’s capital interest, the aggregate ofi. the money so distributed,
ii. all amounts each of which is the cost amount to the trust, immediately before the distribution, of each such other property;
(a.1) where the particular time is immediately before the time that is immediately before the time of the taxpayer’s death and sections 653 to 656.1 deem the trust to dispose of property at the end of the day that includes the particular time, the amount that would be determined under subparagraph b if the taxpayer had died on a day that ended immediately before the time that is immediately before the particular time; and
(b) in any other case, the amount determined by the formula
(A − B) × (C / D).
For the purposes of the formula set forth in subparagraph b of the first paragraph,(a) A is the aggregate ofi. all money of the trust on hand immediately before that time,
ii. all amounts each of which is the cost amount to the trust, immediately before that time, of each other property;
iii. (subparagraph repealed);
(b) B is the aggregate of all amounts each of which is the amount of any debt owing by the trust immediately before that time;
(c) C is the fair market value, at that time, of the capital interest or any part thereof in the trust;
(d) D is the fair market value, at that time, of all capital interests in the trust.