Skip to Main Content

Federal Tax Research: Basic Resources

Online and print resources to research federal tax.
Hierarchy of Authority for IRS Guidance and Other

Text description of the hierarchy of authority for IRS guidance in the image. A pyramid showing the Internal Revenue Code (the statutes) just above and more authoritative that the IRS "guidance" category of documents. Just under the statute are the first of two levels of the pyramid considered by the IRS as guidance The first of these levels is the Treasury (tax) Regulations, which are the laws that interpret the statutes. Just less authoritative that the regulation at the center level of the pyramid and the only other level considered by the IRS as guidance are the documents contained in the Internal Revenue Bulletin as follows: Revenue Rulings, Revenue Procedures, Notices, and Announcements. These documents are are not the law, but they must be followed by the IRS. Just less authoritative than these IRS Guidance are two kinds of documents called Written Determinations as follows: Private Letter Rulings and the Technical Advice Memoranda. These are only binding on the specific taxpayer to whom they are addressed. At the lowest and least authoritative level of the pyramid are 5 categories of resources called Other IRS Publications and Information as follows: 1 Forms and Publications, 2 News Releases and Fact Sheets, 3 FAQs, 4 Online Help and Resources, and 5 Videos. These are sources of general information but should not be cited as authority for an interpretation of the law.

Other Pronouncements

Written determinations are not published. They are available on the IRS web site and in some research databases. Here are a links to a few access points.

Private Letter Rulings

A “letter ruling,” also known as a “private letter ruling,” is a written determination issued to a taxpayer by an associate chief counsel office in response to the taxpayer's written inquiry, filed before the filing of returns or reports that are required by the tax laws, about its status for tax purposes or the tax effects of its acts or transaction. Letter rulings are not published in the Internal Revenue Bulletin.

Technical Advice Memorandum

A technical advice memorandum, or TAM, is guidance furnished by the Office of Chief counsel upon request by an IRS director or an area director in response to technical or procedural questions that developed during a proceeding. The advice only applies to that specific case, but can still be useful for research. TAMs are generally made available after all identifiable information removed. However, they are not published in the Internal Revenue Bulletin.

Access Points