26 CAR § 130-150 – Minimum estimated tax — Generally — Arkansas Code § 26-51-912

(a) When a taxpayer files a declaration of estimated tax, it must be either one hundred percent (100%) of the prior year's tax liability or ninety percent (90%) of the tax liability for the current tax year.
(b) To avoid underestimate penalty, estimated tax payments shall be made by the quarterly installment due dates.
(c) If a taxpayer's income varied during the tax year, it may be able to reduce any underestimate penalties by computing the penalties using the annualized method, in which case both forms AR2220A and AR2220 should be completed.