REVENUE MEMORANDUM CIRCULAR NO. 43-2023 issued on April 14, 2023 further clarifies certain policies on the filing of appeal against Final Decision on Disputed Assessments (FDDA) pursuant to Revenue Regulations No. 12-99, as amended.
        In case of filing of an appeal against the FDDA, the taxpayer shall furnish a copy of the said appeal to the Chief of the Assessment Division for regional cases, or the concerned Head Revenue Executive Assistant, in the case of taxpayers under the jurisdiction of the Large Taxpayers Service or investigated by the National Investigation Division under the Enforcement and Advocacy Service, within five (5) days from date of filing with the Office of the Commissioner of Internal Revenue or the Court of Tax Appeals.