P.R. Laws tit. 21, § 652
In the case of an amount collected under subsection (f) of § 651p of this title interest shall be charged at the same time as said amount, and as part of the tax, at the rate of ten percent (10%) annually on said amount, from the date of notice of the assessment under subsection (a) of § 651p of this title until the date of notice and demand under subsection (f) of § 651p of this title. If the amount included in the notice and demand by the Finance Director under subsection (f) of § 651p of this title should not be fully paid within ten (10) days after said notice and demand, then, as part of the tax, there shall be charged interest on the unpaid amount at the rate of ten percent (10%) annually from the date of said notice and demand until the date of its payment. There shall be charged also, except in the cases in which under subsection (d) of § 651p of this title the stay of the collection of the deficiency has been decreed, the following surcharges after notice and demand by the Finance Director:
(1) For delay in payment of thirty (30) days or less in the payment there shall be no charge;
(2) for delay in payment in excess of thirty (30) days, but not exceeding sixty (60) days, five percent (5%) of the unpaid amount, or
(3) for delay in payment for more than sixty (60) days, ten percent (10%) of the unpaid amount.
History —July 10, 1974, No. 113, Part 1, p. 371, § 28; Nov. 17, 1992, No. 93, § 18.