Tax expenditures (TEs) are deviations from a benchmark tax system. The benchmark acts as a reference point and should not be interpreted as optimal from a tax policy perspective. A benchmark tax system is typically defined using one, or some combination, of the following three approaches (OECD, DIAN and Minhacienda, 2021[1]):
Reference tax law approach. Under this approach, a country’s existing tax system becomes the starting point for defining the benchmark. A TE is an explicit concession that departs from what is considered a generally applicable tax provision under the existing tax law.
Conceptual approach. This approach defines a normative benchmark tax system based on a theoretical concept of comprehensive income or consumption that provides guidance on how tax policy should be defined, irrespective of whether this benchmark accurately reflects existing tax law.
Expenditure subsidy approach. This approach seeks to cost only those concessions that are clearly analogous to an expenditure subsidy. This method is rarely used in practice (see (Australian Government the Treasury, 2021[2]) for an example) and it would likely result in a narrower list of TEs than under the other two approaches.
While most countries follow a reference tax law approach (see Table A A.1), some countries apply a hybrid approach defining the benchmark more broadly than under a legal reference approach by including some of the most fundamental aspects of the tax systems into the benchmark. For example, Canada defines its tax benchmark as the “tax structure that is characterized only by the most fundamental aspects of a tax system” (Department of Finance Canada, 2021[3]). In a similar spirit the Australian TE reports states “The choice of tax benchmark unavoidably involves judgment and therefore, may be contentious in some cases. These judgments are informed by long-standing features of the tax system, practice in TE publications in other jurisdictions and consultation with stakeholders.” (Australian Government the Treasury, 2021[2]) Finally, all TE reports that follow a mixed approach indicate that the tax benchmark should not be interpreted as an indication of the way activities or taxpayers ought to be taxed.