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ABA Tax Challenge Research Guide: Tax Law Research, Continued

What's covered in this section

This section of the guide will discuss sources of primary tax law materials while providing some context as to the weight of authority and precedential value inherent in each type of source. Please keep in mind that agencies vary on these and that the information here is only specific to research on federal tax. This section is broken into two subsections, this one discusses tax statutes, regulations and case law and there is a second subsection on IRS Guidance.

Federal Enacted Law

Internal Revenue Code

From the Internal Revenue Manual § : "The Internal Revenue Code of 1986 is the primary source of Federal tax law. It imposes income, estate, gift, employment, miscellaneous excise taxes, and provisions controlling the administration of Federal taxation. The Code is found at Title 26 of the United States Code (USC). The United States Code consists of fifty titles."

The Internal Revenue Code is codified at Title 26 of the U.S.C. and is available in many databases including:

  • Westlaw
  • CCH Tax Compliance Library (Cheetah)
  • The Standard Federal Tax Reporter
  • The IRS Website

Tax Regulation and Other Administrative Materials

For some context of the purpose and scope of regulations, note the following:

  • Tax regulations are issued by the Internal Revenue Service and Treasury Department to provide guidance for new legislation or to address issues that arise with respect to existing Internal Revenue Code sections.
  • They interpret and give directions on complying with the law. 
  • They are published in the Federal Register and codified in the Code of Federal Regulations. 

The regulation-creating procedure is also helpful to know a bit more about..

  1. Generally, regulations are first published in proposed form in a Notice of Proposed Rulemaking ("NPRM"). 
  2. After public input is fully considered through written comments and even a public hearing, a final regulation or a temporary regulation is published as a Treasury Decision (T.D.), 
  3. It is published again in the Federal Register, in the Internal Revenue Bulletins (I.R.B.), and in the Cumulative Bulletin (C.B.) (C.B.s were published until ‘08).
  4. Treasury Decisions (either final or temporary regulations) are numbered sequentially. 

Where to find tax regulations:

  • the CFR/eCFR
  • GPO FDSys
  • Westlaw Edge
  • Internal Revenue Bulletin & Cumulative Internal Revenue Bulletin

Tax Case Law

Any federal reporter which publishes decisions of those courts which adjudicate federal tax disputes may contain judicial tax case law. The Internal Revenue Bulletin (IRB) also contains judicial tax case law. Below are examples and locations of some reporters which focus on cases involving federal tax issues. 

  • U.S. Tax Court Memorandum Decisions 
    • Lower floor, KF 6324 A5C65
  • Standard Federal Tax Reporter 
    • Upper and Lower Floor, KF6285.C6S7
  • U.S. Tax Reporter
    • Lower Floor, KF6285 P742
  • American Federal Tax Reports
    • Lower Floor, KF 6280 A2A52
  • Internal Revenue Bulletins 

More information about the Internal Revenue Bulletin

What is it?

The Internal Revenue Bulletin (IRB) is the authoritative instrument for announcing official rulings and procedures of the IRS and for publishing Treasury Decisions, Executive Orders, Tax Conventions, legislation, court decisions, and other items of general interest. 

It is published weekly and the types of documents that may be published in the IRB  include: Actions on Decisions, Announcements, Congressional committee reports / Bluebooks, Delegation orders, Executive orders, Notices, Proposed & final regulations/Treasury decisions, Public laws, Revenue rulings, Revenue procedures, Select court decisions.

Where can you find it?

  • Standard Federal Tax Reporter
  • Internal Revenue Bulletin website IRS website
  • Government Printing Office Website 
  • Lexis
  • Westlaw
  • IRA Checkpoint

What finding tools are available?

There is a cumulative index in the last bulletin issued each month that indexes the matters published during the preceding months;

  • These monthly indexes are cumulated on a semiannual basis, and are published in the last Bulletin of each semiannual period.”
  • Example: a cumulative list of all revenue rulings, revenue procedures, Treasury decisions, etc., published in Internal Revenue Bulletins 2016 – 01 through 2016 –26 is in Internal Revenue Bulletin 2016 –26, dated June 27, 2016.

What is authoritative? 

The following items printed in the IRB constitute authority: 

  • Revenue Rulings (not Letter Rulings)
  • Revenue Procedures
  • Notices
  • Announcements

Items that are not in the IRB can still be used as authority but they cannot be cited as precedent per IRS code section 6110(k)(3). This may include:

Actions on Decisions (Legal memoranda that announces the position of the Internal Revenue Service on an adverse decision by a trial or appellate court and whether it should acquiesce (appeal or not) in an adverse U.S. Tax Court decision.)

General counsel memoranda (GCM) up to 2002/ chief counsel advisories (CCAs) post 2002 (indicating the reasoning and authority used in revenue rulings, PLRs, and TAMs. IRS personnel use them in formulating positions.)

IRS written determinations including

  • Technical Advice Memorandum s (TAMs)
  • Letter Rulings (including various items variously titled at different times)

Other authority which cannot be cited as precedent includes: legal advice items issued to assist IRS personnel in administration; administrative manuals and instructions; program plans and reports; training and reference materials; unreleased documents like advanced pricing agreements; documents that are not available on the IRS website; IRS operating division documents.


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