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Tax Research - Federal

This research guide highlights important sources and provides tips for researching federal tax law.

Guidance Documents Types

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The Internal Revenue Service (I.R.S.) is part of the Treasury Department. While guidance documents published by the I.R.S. are not as authoritative as Treasury Regulations, they can be cited by taxpayers as substantial authority in avoiding the understatement of income tax liability penalty under I.R.C. § 6662. They also provide insight to taxpayers and researchers on tax issues. Guidance documents with substantial authority include the following categories:

  1. A Revenue Ruling (Rev. Rul.) is an official IRS interpretation of tax law (the Code, related statutes, treaties, or regulations) with respect to a specific set of facts. Any taxpayer whose circumstances are substantially the same as those described in the ruling can rely upon it.
  2. Revenue Procedures (Rev. Proc.) are published statements of I.R.S. practices and procedures that affect taxpayers' rights and duties under the Code, related statutes, tax treaties, and regulations.
  3. Notices provide guidance before revenue rulings, revenue procedures, and regulations are available.
  4. Announcements (Ann.) alert taxpayers to a variety of information but are somewhat less formal than revenue rulings, revenue procedures, and notices.
  5. A Private Letter Ruling (PLR) is a written response to a taxpayer request for guidance as to a proposed transaction's tax consequence.
  6. Determination letters are similar to private letter rulings, except that they are produced by the IRS district offices rather than the national office.
  7. The IRS issues Technical Advice Memoranda (TAM) in response to IRS requests arising out of tax return examinations.

The IRS publishes the first four categories (Revenue Rulings, Revenue Procedures, Notices, and Announcements) in its weekly Internal Revenue Bulletin (I.R.B.).

In addition to the seven types of documents listed above, other guidance documents exist that do not hold substantial legal authority but that still help researchers and taxpayers to understand the IRS's position on relevant issues. These include Chief Counsel Memoranda (Field Service Advice Memoranda, Litigation Guideline Memoranda, General Counsel Memoranda, and Technical Memoranda) IRS forms and instructions, and other documents.

("Internal Revenue Service" photo by Ray Tsang, license: https://creativecommons.org/licenses/by-sa/2.0/)

Finding IRS Guidance Documents

IRS Guidance Documents are available on the IRS website (under "News & Events," click on "IRS Guidance"), Checkpoint (links under "Search tools"), Intelliconnect (under "Federal Tax Primary Sources," then "IRS Administrative Rulings"), Bloomberg Law (Go to the "Tax Practice Center"), Westlaw, and Lexis. Hein Online has older versions of the Internal Revenue Bulletin (1919-2008) in the Cumulative Bulletin.

Citing Guidance Documents

The Bluebook has special citation formats for tax materials. To see citation formats for IRS Guidance Documents, see T1 (20th ed. pp. 241-42).

More Information

The IRS Guidance Primer provides a brief explanation of the most common types of guidance documents.

An overview of guidance documents with more detailed explanations can be found in Chapter 9 of Gail Levin Richmond, Federal Tax Research: Guide to Materials and Techniques (9th ed. 2014).

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