(1) Section 318(a)(5)(C) provides that stock constructively owned by a partnership, estate, trust, or corporation by reason of the application of
section 318(a)(3) shall not be considered as owned by it for purposes of applying
section 318(a)(2) in order to make another the constructive owner of such stock. For example, if two unrelated individuals are beneficiaries of the same trust, stock held by one which is attributed to the trust under
section 318(a)(3) is not reattributed from the trust to the other beneficiary. However, stock constructively owned by reason of
section 318(a)(2) may be reattributed under
section 318(a)(3). Thus, for example, if all the stock of corporations X and Y is owned by A, stock of corporation Z held by X is attributed to Y through A.