(5) If the value of the separate property acquired by the donor as a result of a conversion did not exceed the value of the separate property thus acquired by the donee spouse, the entire separate property thus acquired by the donor is to be considered, for the purposes of this section, as held by him and the donee spouse as community property. If the value (at the time of conversion) of the separate property so acquired by the donor exceeded the value (at that time) of the separate property so acquired by the donee spouse, only a part of the separate property so acquired by the donor (and only the same fractional part of property acquired by him in exchange for such separate property) is to be considered, for purposes of this section, as held by him and the donee spouse as community property. The part of such separate property (or property acquired in exchange for it) which is considered as so held is the same proportion of it which the value (at the time of the conversion) of the separate property so acquired by the donee spouse is of the value (at that time) of the separate property so acquired by the donor. The following example illustrates the application of the provisions of this paragraph: Example. During 1942 the donor and his spouse partitioned certain real property held by them under community property laws. The real property then had a value of $224,000. A portion of the property, then having a value of $160,000, was converted into the donor's separate property, and the remaining portion, then having a value of $64,000, was converted into his spouse's separate property. In 1955 the donor made a gift to his spouse of the property acquired by him as a result of the partition, which property then had a value of $200,000. The portion of the property transferred by gift which is considered as community property is
$64,000 (value of property acquired by donee spouse) / $160,000 (value of property acquired by donor spouse) * $200,000 = $80,000.
The marital deduction with respect to the gift is, therefore, limited to one-half of $120,000 (the difference between $200,000, the value of the gift, and $80,000, the portion of the gift considered to have been of "community property"). The marital deduction with respect to the gift is, therefore, $60,000.