What interest and late-payment penalty apply to a tax paid late in Guatemala?

Two separate, cumulative charges. Compensatory interest (Decreto 6-91, arts. 58–59): on the tax owed, at the maximum simple annual rate the Junta Monetaria sets for tax purposes in the first fifteen days of January and July, based on the banking system's weighted lending rate of the previous half-year; it runs from the legal due date to the day of actual payment. Late-payment penalty (art. 92): applies automatically when payment comes after the legal deadline and equals the tax multiplied by 0.0005 per day of delay; it does not apply to adjustments or ex-officio assessments, which carry the omission penalty of art. 89. Art. 61 grants interest to the taxpayer on undue or excess payments.