2023 Delaware Code › Title 30 - State Taxes › Chapter 5. PROCEDURE, ADMINISTRATION AND ENFORCEMENT › Subchapter III. Procedure and Administration › § 533. Interest on underpayment.

§ 533. Interest on underpayment.
(a) If any amount of tax, including tax required to be withheld by an employer, and including penalties, additional amounts and additions to the tax, imposed by this title or Title 4 is not paid on or before the last date prescribed for payment, interest on such amount at the rate of 0.5% per month, or fraction thereof, shall be payable for the period from such last date to the date such amount is paid, and from and after the date the assessment of such interest becomes final under § 522 or § 530 of this title to the date such amount is paid, such interest shall compound monthly. No interest shall be imposed if the amount due is less than $1.00, nor shall this section apply to any failure to pay estimated income tax under § 1170 or § 1904 of this title.
(b) For purposes of this section, the last date prescribed for payment of any tax shall be determined without regard to any extension of time.
(c) Interest prescribed under this section on any tax, including tax required to be withheld by an employer, and including penalties, additional amounts and additions to the tax, shall be assessed, collected and paid in the same manner as taxes. After an initial assessment of interest upon any amount of tax, penalty, additional amount or addition to the tax, interest shall continue to accrue on the unpaid balance of such amount until such amount has been paid in full, except as otherwise provided in subsection (e) of this section, and no further assessment of such interest shall be made.
(d) Interest shall be imposed under this section in respect of any penalty, additional amount or addition to the tax from the date of the notice of proposed assessment under § 521(c) of this title of such penalty, additional amount or addition to the tax to the date of payment thereof.
(e) If a proposed assessment is made with respect to any amount, and if such amount is paid within 10 days after the date of the notice of proposed assessment thereof under § 521(c) of this title, interest under this section on the amount so paid shall not be imposed for the period after the date of such notice.
(f) If any portion of a tax is satisfied by credit of an overpayment, then no interest shall be imposed under this section on the portion of the tax so satisfied for any period during which, if the credit had not been made, interest would have been allowable with respect to such overpayment.
(g) Any portion of any tax imposed, or any interest, penalty, additional amount or addition to the tax, which has been erroneously refunded and which is recoverable by the Director, shall bear interest at the rate of 0.5% per month, or fraction thereof, from the date of payment of such refund to the date of its recovery by the Director, and from and after the date the assessment of such interest becomes final under § 522 or § 530 of this title to the date of such recovery, such interest shall compound monthly.
(h) Interest prescribed under this section on any tax may be assessed and collected at any time during the period within which the tax, penalty, additional amount or addition to the tax to which such interest relates may be collected.
(i) If the Secretary of the Treasury of the United States extends the time for filing income tax returns under § 6081 of the Internal Revenue Code (26 U.S.C. § 6081) and the time for paying income tax with respect to such returns under § 6161 of the Internal Revenue Code (26 U.S.C. § 6161) for any taxpayer located in a Presidentially-declared disaster area, the Director shall abate for such period the assessment of any interest prescribed under this section and penalties for failure to file a return under § 534(a) of this title or to pay the tax under § 534(b) of this title on such taxpayer's income and business license tax. For purposes of this subsection, the term “Presidentially-declared disaster area” means, with respect to any taxpayer, any area which the President of the United States has determined warrants assistance by the Federal Government under the Disaster Relief and Emergency Assistance Act.
68 Del. Laws, c. 187, §  1;  72 Del. Laws, c. 112, §  2;  75 Del. Laws, c. 411, §§  1, 2;