THE withholding tax system is a mechanism to facilitate the collection of taxes from taxpayers. In the case of Chamber of Real Estate and Builders' Associations Inc. v. Executive Secretary Alberto Romulo, et al. (GR 60756, March 9, 2010), the Supreme Court stated that the purpose of the system was three-fold: to provide the taxpayer a convenient way of paying a tax liability, to ensure the collection of the tax and to improve the government's cash flow.

Many taxpayers are withholding agents for the government. The obligation to withhold tax has its legal basis in Section 57 of the National Internal Revenue Code as amended (Tax Code) and is primarily governed and implemented by Revenue Regulations 02-98 as amended.