For purposes of subparagraph (A), an individual shall be disabled if such individual has a mental or physical impairment which renders him unable to materially participate in the operation of the farm or other business.
For purposes of subsection (c)(6)(B)(i), if the requirements of paragraph (1)(C)(ii) are met with respect to any decedent by reason of subparagraph (A), the period ending on the date on which the continuous period taken into account under subparagraph (A) began shall be treated as the period immediately before the decedent’s death.
If property is qualified real property with respect to a decedent (hereinafter in this paragraph referred to as the “first decedent”) and such property was acquired from or passed from the first decedent to the surviving spouse of the first decedent, for purposes of applying this subsection and subsection (c) in the case of the estate of such surviving spouse, active management of the farm or other business by the surviving spouse shall be treated as material participation by such surviving spouse in the operation of such farm or business.
In any case in which to do so will enable the requirements of paragraph (1)(C)(ii) to be met with respect to the surviving spouse, this subsection and subsection (c) shall be applied by taking into account any application of paragraph (4).
For purposes of subparagraph (B), the term “adjusted tax difference with respect to the estate” means the excess of what would have been the estate tax liability but for subsection (a) over the estate tax liability. For purposes of this subparagraph, the term “estate tax liability” means the tax imposed by section 2001 reduced by the credits allowable against such tax.
For purposes of this subsection, a surviving spouse or lineal descendant of the decedent shall not be treated as failing to use qualified real property in a qualified use solely because such spouse or descendant rents such property to a member of the family of such spouse or descendant on a net cash basis. For purposes of the preceding sentence, a legally adopted child of an individual shall be treated as the child of such individual by blood.
The term “qualified heir” means, with respect to any property, a member of the decedent’s family who acquired such property (or to whom such property passed) from the decedent. If a qualified heir disposes of any interest in qualified real property to any member of his family, such member shall thereafter be treated as the qualified heir with respect to such interest.
In the case of real property which meets the requirements of subparagraph (C) of subsection (b)(1), residential buildings and related improvements on such real property occupied on a regular basis by the owner or lessee of such real property or by persons employed by such owner or lessee for the purpose of operating or maintaining such real property, and roads, buildings, and other structures and improvements functionally related to the qualified use shall be treated as real property devoted to the qualified use.
Material participation shall be determined in a manner similar to the manner used for purposes of paragraph (1) of section 1402(a) (relating to net earnings from self-employment).
If there is no comparable land from which the average annual gross cash rental may be determined but there is comparable land from which the average net share rental may be determined, subparagraph (A)(i) shall be applied by substituting “average annual net share rental” for “average annual gross cash rental”.
If the decedent and his surviving spouse at any time held qualified real property as community property, the interest of the surviving spouse in such property shall be taken into account under this section to the extent necessary to provide a result under this section with respect to such property which is consistent with the result which would have obtained under this section if such property had not been community property.
If the qualified heir makes written application to the Secretary for determination of the maximum amount of the additional tax which may be imposed by subsection (c) with respect to the qualified heir’s interest, the Secretary (as soon as possible, and in any event within 1 year after the making of such application) shall notify the heir of such maximum amount. The qualified heir, on furnishing a bond in such amount and for such period as may be required, shall be discharged from personal liability for any additional tax imposed by subsection (c) and shall be entitled to a receipt or writing showing such discharge.
The term “active management” means the making of the management decisions of a business (other than the daily operating decisions).
In the case of any qualified replacement property, any period during which there was ownership, qualified use, or material participation with respect to the replaced property by the decedent or any member of his family shall be treated as a period during which there was such ownership, use, or material participation (as the case may be) with respect to the qualified replacement property.
The Secretary shall prescribe regulations setting forth the application of this section and section 6324B in the case of an interest in a partnership, corporation, or trust which, with respect to the decedent, is an interest in a closely held business (within the meaning of paragraph (1) of section 6166(b)). For purposes of the preceding sentence, an interest in a discretionary trust all the beneficiaries of which are qualified heirs shall be treated as a present interest.
The rules of the last sentence of section 1033(a)(2)(A) shall apply for purposes of paragraph (3)(B)(ii).