R.I. Gen. Laws § 44-11-26 — Pecuniary penalty for failure to file return or to pay tax or for negligence

(a) In the case of any failure to file a return within the time prescribed by law, there
shall be added to the tax five percent (5%) if the failure is for not more than one
month, with an additional five percent (5%) for each additional month or fraction
of a month during which the failure continues, not exceeding twenty-five percent (25%)
in the aggregate, except that when a return is filed after the time prescribed by
law and it is shown that the failure to file the return at the prescribed time was
due to reasonable cause and not due to willful neglect, no addition to the tax shall
be made.
(b) In the case of any failure to pay the tax as imposed by this chapter with the return
on or before the date prescribed by law (determined with regard to any extension of
time for payment), there shall be added to the amount shown as tax on the return five-tenths
percent (0.5%) of the amount of the tax if the failure is for not more than one month,
with an additional five-tenths percent (0.5%) for each additional month or fraction
of a month during which the failure continues, not exceeding twenty-five percent (25%)
in the aggregate, except that when the failure is due to reasonable cause and not
to willful neglect, no addition to the tax shall be made.
(c) In the case of any failure to pay any amount in respect of any tax required to be
shown on a return, which is not shown, including an assessment made as a result of
mathematical error, within thirty (30) days of the date of the notice and demand,
there shall be added to the amount of tax stated in the notice and demand five-tenths
percent (0.5%) of the amount of the tax if the failure is for not more than one month,
with an additional five-tenths percent (0.5%) for each additional month or fraction
of a month during which the failure continues, not exceeding twenty-five percent (25%)
in the aggregate, except that when the failure is due to reasonable cause and not
to willful neglect, no addition to the tax shall be made.
(d) If any part of a deficiency is due to negligence or intentional disregard of the Rhode
Island business corporation tax law or rules or regulations hereunder, but without
intent to defraud, five percent (5%) of that part of the deficiency shall be added
to the tax. This amount shall be in lieu of any other additional amount imposed by
subsection (b) of this section.