account shall be maintained separately from any SLDO account otherwise maintained by such heir. (g) Treatment of trusts and estates as applicable taxpayers For purposes of this chapter— (1) In general Any trust (other than a trust the assets of which are treated as owned by another taxpayer under subpart E of part I of subchapter J of chapter 1) or applicable estate shall be treated as an applicable taxpayer for purposes of this chapter if any assets of the trust are trust attributed assets with respect to any applicable taxpayer. (2) Applicable estate An estate is an applicable estate if the decedent was an applicable taxpayer for any taxable year ending during the 5-year period ending on the date of the decedent’s death, except that such estate shall not be treated as an applicable taxpayer for any taxable year beginning before the third taxable year following the date of the decedent’s death. (3) Trusts acquiring United States beneficiaries (A) In general If paragraph (1) applies to a trust for a transferor or beneficiary’s taxable year, and paragraph (1) would have applied to the trust for any of the preceding 10 taxable years (other than years prior to the effective date of this section) but for the fact that in such year or years there was no United States beneficiary for any portion of the trust, then the transferor shall be treated as having income for the taxable year equal to— (i) the aggregate increases in the tax imposed under this title for each such prior taxable year (beginning after the date of the enactment of this chapter) which would have occurred if paragraph (1) had applied to such trust for such year, plus (ii) interest on such increase determined with respect to each such taxable year determined at the underpayment rate. (B) No living transferor In the event that subparagraph (A) would apply, but for the fact that there is no living transferor, then each beneficiary of such trust, other than a contingent beneficiary, shall be treated as having income for the taxable year equal to— (i) the