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Federal Tax Law Research

Statutes, Regs, Cases, etc...


The statutes that regulate taxation are often referred to as the Internal Revenue Code (I.R.C. or "the Code"). They appear in the United States CodeUnited States Code Annotated, and United States Code Service. The statutes are also printed in two major looseleaf services: CCH's Standard Federal Tax Reporter and RIA's United States Tax Reporter. There are three major versions of the Code: 1939, 1954 and 1986.


The Internal Revenue Service makes rules and regulations to implement the statutes. Taxation regulations are codified under Title 26 of the Code of Federal Regulations (C.F.R.). Final and temporary tax regulations are issued as Treasury Decisions (T.D.s), and published in the Cumulative Bulletin (C.B.). The Federal Register also publishes proposed, temporary and final regulations. CCH's Standard Federal Tax Reporter and RIA's United States Tax Reporter include regulations, organized by Code section.

Note: Tax regulation section numbers start with a numerical designation of the type of tax issue involved. Common classifications are: 1. Income Tax; 20. Estate Tax; 25. Gift Tax; 31. Employment Tax; 301 Procedural Matters. The numbers after the decimal start with the number of the Code section under which they are promulgated. E.g., 26 C.F.R. 1.167(a)-1 is the first regulation under the income tax code section 167(a).

Other Administrative Materials

The following official documents are all published in the Internal Revenue Bulletin (I.R.B.). This weekly publication is cumulated twice yearly in the Cumulative Bulletin (C.B.).

  • Treasury Decisions. Final and temporary tax regulations. Authoritative.

  • Proposed regulations. Not authoritative.

  • Revenue Rulings. Ruling applying the law to particular facts presented by a taxpayer. Authoritative for same factual circumstances, unless officially revoked.

  • Other notices (for example, meeting notices).

Other documents (to find where these are published, see chart below):

  • Private Letter Rulings (P.L.R's or L.T.R's). Written by the I.R.S. National Office in response to a taxpayer. They interpret specific facts. Letter rulings are assigned a file number (e.g., 8102077) in which the first two digits show the year of issuance, the next digits show the week of issuance, and the remaining digits show the order of issuance in that particular week. Not authoritative.

  • Technical Advice Memoranda (T.A.M.'s). Contain advice from the I.R.S. National Office to an I.R.S. District Director Appeals Officer (auditor). Not authoritative.

  • General Counsel Memoranda (G.C.M.)-issued by the I.R.S. Office of Chief Counsel to explain reasoning and authority underlying revenue rulings, letter rulings, and technical advice memoranda. Not authoritative.

  • Action on Decision (A.O.D.)-memo published by I.R.S. counsel to indicate whether Commissioner should appeal, acquiesce in or not acquiesce in a Tax Court decision.

  • Transmittal or Technical Memoranda-background information prepared to accompany published regulations (in addition to the preamble introducing the regulation).

  • Operating policies. Internal I.R.S. procedures.

Judicial Decisions

The United States Tax Court issues two kinds of decisions: Regular decisions and Memo decisions. The Tax Court Regular Opinions are published in the United States Tax Court Reports (official publication; Looseleaf Services KF 6324 .A5 U54). Tax Court Memo Decisions are not published officially.

All Tax Court decisions are published in the CCH Tax Court Reporter (Looseleaf KF 6324 .A6 U65) and RIA's Tax Court Reported and Memorandum Decisions (Looseleaf KF 6324 .A5 U544). Older decisions are moved to transfer binders.

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