S6166_Paragraph
(k4) - Section 6166(k)(4) - Interest - Section 6601(j)
Section 6601(j) Example 1 Worksheet - Date of Death May-10-2016
1Gross estate30,000,000.00
2Sections 2053 and 2054 deductions2,750,000.00 
3Section 2056 or 2056A marital deduction0.00
4Section 2055 charitable deduction3,000,000.00
5Total deductions5,750,000.00
6Tentative taxable estate24,250,000.00
7State death tax deduction3,344,000.00
8Tentative taxable estate less state death tax deduction20,906,000.00
9Adjusted taxable gifts0.00
10Taxable estate20,906,000.00
11Tentative estate tax8,308,200.00
12Gift tax paid or payable0.00
13Gross estate tax8,308,200.00
14Applicable credit amount2,125,800.00
15Net estate tax6,182,400.00
Determining the §6166(a)(2) Ratio
16Gross estate30,000,000.00
17Sections 2053 and 2054 deductions2,750,000.00
18Section 6166(b)(6) adjusted gross estate27,250,000.00
19Closely held business value20,000,000.00
20Section 6166(a)(2) ratio for the maximum amount of tax which may be paid in installments0.733945
Determining the Maximum Amount of Tax Which May be Paid in Installments
21Net estate tax6,182,400.00
22Section 6166(a)(2) ratio for the maximum amount of tax which may be paid in installments0.733945
23Maximum amount of tax which may be paid in installments4,537,541.57
24Tax not deferred and payable on the return due date1,644,858.43

The line 23 amount is the maximum amount of tax which may be paid in installments. However, we cannot say what the annual installment is until we determine under which specific subsection in the election statement the tax is being deferred - §6166(a), §6166(b)(7), §6166(b)(8)(A), §6166(b)(8)(B)(ii), or §6166(b)(10).

Section 6601(j) Example 1
Determining the §6601(j)(2) 2% and §6601(j)(1)(B) 45% of R% Portions of Deferred Tax
 §6166(a)§6166(b)(7)§6166(b)(8)(A)§6166(b)(8)(B)(ii)§6166(b)(10)
§6601(j)(2) 2% portion of deferred tax592,000.000.000.000.00592,000.00
§6601(j)(1)(B) 45% of R% portion of deferred tax3,945,541.574,537,541.574,537,541.574,537,541.573,945,541.57
Total deferred tax amount4,537,541.574,537,541.574,537,541.574,537,541.574,537,541.57
Maximum number of annual installments10101055
Annual installment453,754.16453,754.16453,754.16907,508.31907,508.31

The interplay among sections 6601(j) and 6166(a), 6166(b)(7), 6166(b)(8)(A), 6166(b)(8)(B)(ii), and 6166(b)(10) results in the table example shown above.

Section 6601(j) Example 1
Determining the §6601(j) Interest Payable on the 1st Anniversary Date of Feb-10-2018
 §6166(a)§6166(b)(7)§6166(b)(8)(A)§6166(b)(8)(B)(ii)§6166(b)(10)
Total deferred tax4,537,541.574,537,541.574,537,541.574,537,541.574,537,541.57
First installment due on the return due date of Feb-10-20170.00453,754.16453,754.16907,508.31907,508.31
Balance on which §6601(j) interest is computed to the 1st anniversary date of Feb-10-20184,537,541.574,083,787.414,083,787.413,630,033.263,630,033.26
§6601(j)(2) portion at 2% rate592,000.000.000.000.00473,600.00
§6601(j)(1)(B) portion at 45% of R% rate3,945,541.574,083,787.414,083,787.413,630,033.263,156,433.26
§6601(j)(2) 2% interest due11,958.860.000.000.009,567.09
§6601(j)(1)(B) 45% of R% interest due71,660.9974,171.8974,171.8965,930.5757,328.79
Total interest due Feb-10-201883,619.8574,171.8974,171.8965,930.5766,895.88
2nd installment due0.00453,754.16453,754.16907,508.31907,508.31
Total amount due Feb-10-201883,619.85527,926.05527,926.05973,438.88974,404.19

If the first installment due on the return due date was not paid then but was paid with the return filed on an extended filing due date 6 months later, interest due on that first installment (from the return due date through the payment date 6 months later) would be calculated pursuant to section 6621, not section 6601(j). 

See Rev. Rul. 89-32, 1989-1 C.B. 307.