This compendium gathers basic information concerning approximately 250 federal tax provisions currently treated as tax expenditures. They include those listed in Tax Expenditure Budgets prepared for fiscal years 2010-2014 by the Joint Committee on Taxation, although certain separate 1 items that are closely related and are within a major budget function may be combined. The Joint Committee on Taxation also lists 31 additional tax expenditures with deminimis revenue losses (i.e., less that $50million over 5 years).

With respect to each tax expenditure, this compendium provides:

• The estimated federal revenue loss associated with the provision for individual and corporate taxpayers, for fiscal years 2010-2014, as estimated by the Joint Committee on Taxation;
• The legal authorization for the provision (e.g., Internal Revenue Code section, Treasury Department regulation, or Treasury ruling);
• A description of the tax expenditure, including an example of its operation where this is useful;
• A brief analysis of the impact of the provision, including information on the distribution of benefits where data are available;
• A brief statement of the rationale for the adoption of the tax expenditure where it is known, including relevant legislative history;
• An assessment, which addresses the arguments for and against the provision; and
• References to selected bibliography.

The information presented for each tax expenditure is not intended to be exhaustive or definitive. Rather, it is intended to provide an introductory understanding of the nature, effect, and background of each provision. Useful starting points for further research are listed in the selected bibliography following each provision.