Period to assess, collect tax

The period to assess and collect an internal revenue tax is limited only to three years by Section 203 of the NIRC of 1997, as amended, quoted hereunder as follows:
SEC. 203. Period of Limitation Upon Assessment and Collection. – Except as provided in Section 222, internal revenue taxes shall be assessed within three years after the last day prescribed by law for the filing of the return, and no proceeding in court without assessment for the collection of such taxes shall be begun after the expiration of such period: Provided, That in a case where a return is filed beyond the period prescribed by law, the three (3)-year period shall be counted from the day the return was filed.

For purposes of this Section, a return filed before the last day prescribed by law for the filing thereof shall be considered as filed on such last day. (Emphasis supplied)
This mandate governs the question of prescription of the government’s right to assess internal revenue taxes primarily to safeguard the interests of taxpayers from unreasonable investigation by not indefinitely extending the period of assessment and depriving the taxpayer of the assurance that it will no longer be subjected to further investigation for taxes after the expiration of reasonable period of time (CIR v. FMF Dev't. Corp., 579 Phil. 174, 183 [2008]).