Section 2523(c) provides that if an interest passing to a donee spouse may be satisfied out of a group of assets (or their proceeds) which include a particular asset that would be a nondeductible interest if it passed from the donor to his spouse, the value of the interest passing to the spouse is reduced, for the purpose of the marital deduction, by the value of the particular asset.

In order for this section to apply, two circumstances must coexist, as follows:

The property interest transferred to the donee spouse must be payable out of a group of assets. An example of a property interest payable out of a group of assets is a right to a share of the corpus of a trust upon its termination.

The group of assets out of which the property interest is payable must include one or more particular assets which, if transferred by the donor to the donee spouse, would not qualify for the marital deduction. Therefore, section 2523 (c) is not applicable merely because a group of assets includes a terminable interest, but would only be applicable if the terminable interest were nondeductible under the provisions of § 25.2523(b)-1.

If both of the circumstances set forth in paragraph (b) of this section exist, only a portion of the property interest passing to the spouse is a deductible interest. The portion qualifying as a deductible interest is an amount equal to the excess, if any, of the value of the property interest passing to the spouse over the aggregate value of the asset (or assets) that if transferred to the spouse would not qualify for the marital deduction. See paragraph (c) of § 25.2523(a)-l to determine the percentage of the deductible interest allowable as a marital deduction. The application of this section may be illustrated by the following example:

H was absolute owner of a rental property and on July 1, 1950, transferred it to A by gift, reserving the income for a period of 20 years. On July 1, 1955, he created a trust to last for a period of 10 years. H was to receive the income from the trust and at the termination of the trust the trustee is to turn over to H's wife, W, property having a value of $100,000. The trustee has absolute discretion in deciding which properties in the corpus he shall turn over to W in satisfaction of the gift to her. The trustee received two items of property from H. Item (1) consisted of shares of corporate stock. Item (2) consisted of the right to receive the income from the rental property during the unexpired portion of the 20-year term. Assume that at the termination of the trust on July 1, 1965, the value of the right to the rental income for the then unexpired term of 5 years (item (2)) will be $30,000. Since item (2) is a nondeductible interest and the trustee can turn it over to W in partial satisfaction of her gift, only $70,000 of the $100,000 receivable by her on July 1, 1965, will be considered as property with respect to which a marital deduction is allowable. The present value on July 1, 1955, of the right to receive $70,000 at the end of 10 years is $49,624.33 as determined under § 25.2512-5A(c). The value of the property qualifying for the marital deduction, therefore, is $49,624.33 and a marital deduction is allowed for one-half of that amount, or $24,812.17.