Section 2516 provides that transfers of property or interests in property made under the terms of a written agreement between spouses in settlement of their marital or property rights are deemed to be for an adequate and full consideration in money or money's worth and, therefore, exempt from the gift tax (whether or not such agreement is approved by a divorce decree), if the spouses obtain a final decree of divorce from each other within two years after entering into the agreement.
See paragraph (b) of § 25.6019-3 for the circumstances under which information relating to property settlements must be disclosed on the transferor's gift tax return for the “calendar period” (as defined in § 25.2502-1(c)(1)) in which the agreement becomes effective.