National Internal Revenue Code (NIRC)
Section 75. Declaration of Quarterly Corporate Income Tax. - Every corporation shall file in duplicate a quarterly summary declaration of its gross income and deductions on a cumulative basis for the preceding quarter or quarters upon which the income tax, as provided in Title II of this Code, shall be levied, collected and paid. The tax so computed shall be decreased by the amount of tax previously paid or assessed during the preceding quarters and shall be paid not later than sixty (60) days from the close of each of the first three (3) quarters of the taxable year, whether calendar or fiscal year.