(1) In general. For purposes of--
(A) section 303(b) (relating to distributions in redemption of stock to pay death taxes),
(B) section 2032A (relating to special valuation of certain farms, etc., real property), and
(C) subchapter C of chapter 64 (relating to lien for taxes),
the value of the gross estate shall include the value of all property to the extent of any interest therein of which the decedent has at any time made a transfer, by trust or otherwise, during the 3-year period ending on the date of the decedent's death.
(2) Coordination with section 6166. An estate shall be treated as meeting the 35 percent of adjusted gross estate requirement of section 6166(a)(1) only if the estate meets such requirement both with and without the application of subsection (a).
(3) Marital and small transfers. Paragraph (1) shall not apply to any transfer (other than a transfer with respect to a life insurance policy) made during a calendar year to any donee if the decedent was not required by section 6019 (other than by reason of section 6019(2)) to file any gift tax return for such year with respect to transfers to such donee.