Section 13-602 - Deficiency in estimated tax(a) Except as provided in subsections (b) and (c) of this section, a tax collector shall assess interest on unpaid tax from the due date to the date on which the tax is paid if a person who is required to estimate and pay digital advertising gross revenues tax, financial institution franchise tax, public service company franchise tax, or income tax under § 7.5-301, § 8-210(b), § 8-405(b), or § 10-902 of this article: (1) fails to pay an installment when due; or(2) estimates a tax that is: (i) less than 90% of the tax required to be shown on the return for the current taxable year; and(ii) less than 110% of the tax paid for the prior taxable year, reduced by the credit allowed under § 10-703 of this article.(b) Interest may not be assessed on the underestimation of individual income tax if:(1) at least 90% of the individual's taxable income is also taxable by another state; and(2) the underestimation is of the county income tax only.(c) A tax collector may not assess interest on unpaid individual income tax under subsection (a) of this section if the amount of unpaid income tax is less than one-half the amount specified in § 6654(e)(1) of the Internal Revenue Code.Amended by 2021 Md. Laws, Ch. 37,Sec. 2, eff. 3/12/2021.