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Tax Law

A guide to federal tax law research.


Treasury regulations are the IRS's official and authoritative interpretation of the IRC.  Regulations are first published as "proposed" regulations, which allows for a public comment period before the regulations become final.  Final regulations are issued as Treasury Decisions (TD's) and are numbered in order of their issuance.

The IRS may also issue temporary regulations when immediate regulatory action is needed.  Temporary regulations are effective immediately upon publication and remain in effect until final regulations are issued.  Temporary regulations are issued and numbered as Treasury Decisions (TD's).

Proposed regulations and Treasury Decisions can be found in:

Treasury regulations are codified in Title 26 of the Code of Federal Regulations, but they are usually cited as "Treas. Reg." rather than by the CFR title.  Current regulations can be found in:

For regulations in force in prior years, see West's Federal Tax Regulations (1954 to 2002).

IRS Pronouncements

Most IRS documents are published in the weekly Internal Revenue Bulletin ("IRB") (also online).  The IRB is cumulated twice a year and published as the Cumulative Bulletin (also on HeinOnline).  Some documents, like private letter rulings, are not officially published but are available in other sources.  IRS pronouncements published in the IRB are binding authority and must be followed by the IRS.  The current status of IRS pronouncements should be verified with an online citator, either through Lexis, Westlaw, or one of the major looseleafs.

  • Revenue Rulings  A revenue ruling is a pronouncement on a specific factual situation that has been submitted by a taxpayer, published for the guidance of all taxpayers.  It doesn't carry the force and effect of a regulation but can be cited as precedent by taxpayers with similar situations.  Besides the Internal Revenue Bulletin, revenue rulings can be found in:
  • Revenue Procedures  A revenue procedure is an IRS statement of internal IRS practice and procedure used in the implementation and administration of the tax laws.  A revenue procedure can be relied on by a taxpayer if his facts and circumstances are essentially the same as those in the revenue procedure.  Besides the IRB, revenue procedures can be found in:
  • Private Letter Rulings  A private letter ruling ("PLR") is issued by the IRS in response to a taxpayer's request for the IRS position on a specific tax issue.  The rulings have been made public by the IRS since 1976.  Unlike revenue rulings, PLR's are not officially published and are not binding on the IRS.  However, a PLR does show the probable IRS approach to a specific sitation.  PLR's can be found in:
  • Other Pronouncements  The IRS issues other pronouncements, including: General Counsel Memoranda, Technical Memoranda, and Actions on Decisions.  These are not published by the IRS, and can be found in the major looseleafs and tax databases, and on Westlaw.