GW Law Library: Library Guides: Tax Law: Primary Sources

About Tax Law Primary Sources

When researching federal tax law, you may need to review the following primary sources: Internal Revenue Code (I.R.C.), other non-codified federal tax statutes (like tax treaties), final and temporary regulations, judicial decisions on tax matters, revenue rulings, revenue procedures, and other published IRS positions.

A helpful overview of IRS primary documents is U.S. Internal Revenue Service, Tax code, regulations, and official guidance.

Laws & Amendments

U.S. Code:

Current federal tax law is found in Title 26 of the United States Code (U.S.C.) and known as the Internal Revenue Code (I.R.C.). Cite to the Internal Revenue Code, instead of the U.S. Code. Example: I.R.C. § 61. Consult Bluebook Rule 12.9.1 for additional information.

Title 26: Internal Revenue Code (I.R.C.)

Public Laws:

Before laws are codified--that is, organized by subject--and published in the U.S. Code, they are first issued as "public laws," also known generally as session laws. Public laws can be located using the Library's Federal Statutory Law guide.

Legislative History

A legislative history is a collection of documents (including bills, committee hearings, reports, and debates) produced while legislation is being considered by Congress. It can be useful for determining legislative intent.

Listed below are sources for compiled legislative histories on legislation that has been signed into law and sources for legislative history documents relating to a Senate or House bill which didn't become law.

For additional information on researching legislative histories, consult the Library's Federal Legislative History guide.

Internal Revenue Code Historical Notes (RIA)
The full text of the historical notes of RIA's Complete Internal Revenue Code, which provide legislative history for the Code dating back to 1954.
Internal Revenue Code (RIA)
The full text of RIA's Complete Internal Revenue Code, which contains the entire Internal Revenue Code plus a searchable table of contents and legislative history (historical notes) dating back to 1954.
Proquest Legislative Insight
Provides full-text digital access to congressional publications created during the legislative process leading up to the enactment of a U.S. public law.
Proquest Congressional
Provides access to Legislative Histories (1969-present); Congressional Reports (1819-present); Congressional Hearings (published and unpublished) (1824-present); Congressional Committee Prints (1830-present); U.S. Congressional Serial Set and American State Papers from 1789-1969; and CRS Reports (1916-present). Also contains member biographies, committee assignments, voting records, and financial data.

Treasury Regulations

Treasury regulations, commonly referred to as federal tax regulations, provide the official interpretation of the I.R.C. by the U.S. Department of the Treasury and give directions to taxpayers on how to comply with the I.R.C.'s requirements.

Regulation numbers consist of three parts: a prefix, a code section number, and a subdivision.
Example: Treas. Reg. § 1.61-1

31 C.F.R. Part 10, Practice Before the Internal Revenue Service
Internal Revenue Bulletin (I.R.B.)
The authoritative instrument of the Commissioner of Internal Revenue for announcing official rulings and procedures of the Internal Revenue Service and for publishing Treasury Decisions, Executive Orders, Tax Conventions, legislation, court decisions, and other items of general interest. The Internal Revenue Service ceased publishing the Cumulative Bulletin in 2008.
Treasury Decision / Preambles
Final and proposed regulations are issued as Treasury Decisions before codification in the Code of Federal Regulations. Treasury Decisions contain explanatory preambles which are not included in the C.F.R. and can be helpful to the researcher.
Treasury Regulations

Forms & Publications

Forms, instructions & publications
(U.S. Internal Revenue Service)
Circular 230 - Practice Before the IRS
Bloomberg Tax Research: Practice Tools: Forms
Bloomberg Tax Research: IRS Publications

Court Decisions

Income tax litigation begins in one of three forums. If the taxpayer has not paid the tax, the forum is the United States Tax Court. In this forum, there is no right to a jury trial, but the judges have more tax expertise and sophistication due to the specialized nature of the court. If the taxpayer has paid the disputed tax and is then refused a refund, the forum is either the federal district court (where the taxpayer is entitled to a jury trial) or the Court of Federal Claims.

Appeals from Tax Court and federal district court decisions are to the Circuit Court of Appeals covering the taxpayer's state of residence. Appeals from the Court of Federal Claims are to the United States Court of Appeals for the Federal Circuit.

The U.S. Tax Court issues three types of decisions:

Tax Court Summary Opinions
Summary Opinions are issued by the Small Cases division where the amount in controversy is $50,000 or less. They cannot be relied on as precedent and the decision cannot be appealed.
Tax Court Memorandum Opinions
Memorandum Opinions are the "unpublished" opinions of the Tax Court and usually involve questions of fact where the law is well settled.

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Unofficially published in the commercial reporter Tax Court Memoradum Decisions (T.C.M.). Both CCH and Thomson Reuters (formerly RIA) have competing versions of this reporter, so proper citation is to "T.C.M. (CCH)" or "T.C.M. (RIA)" as applicable.
Tax Court Regular Opinions
Regular Opinions are "published" decisions of the Tax Court designated by the Chief Judge of the Tax Court as containing novel or important issues.

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Published officially in the United States Tax Court Reports (T.C.). Before 1942, the Tax Court was the "Board of Tax Appeals", and its decisions were published in the Board of Tax Appeals Reports (B.T.A.). Regular decisions are also commercially published in CCH's Tax Court Reporter (T.C.R.). CourtListener has all Board of Tax Appeals and United States Tax Court (T.C.) volumes online: https://www.courtlistener.com/c/T.C./ and https://www.courtlistener.com/c/B.T.A./

Reported tax decisions of the district courts, Court of Federal Claims, and the Circuit Courts of Appeal are printed in the reporter applicable to that court, just like any other opinion.

Both reported and "unreported" tax decisions from these courts are also printed in two commercial print reporters: United States Tax Cases (U.S.T.C.) and American Federal Tax Reports (A.F.T.R.). U.S.T.C. is published by CCH, and A.F.T.R. is published by Thomson Reuters (formerly RIA). Each reporter integrates with the applicable publisher's print and electronic finding aids (CCH's Standard Federal Tax Reporter and Cheetah; Thomson Reuters's United States Tax Reporter and Federal Tax Coordinator).

West's Federal Supplement (F. Supp., F. Supp. 2d, F. Supp. 3d)
Tax Opinions of the Federal District Courts.
Federal Reporter (F., F.2d, F.3d)
Tax Opinions of the U.S. Circuit Courts of Appeals and Court of Appeals for the Federal Circuit.
West’s Federal Claims Reporter (Fed. Cl.) (formerly United States Claims Court Reporter)
Cases from the federal courts with original jurisdiction over claims against the United States that relate to taxation by federal, state, or local governments.
U.S. Tax Cases (U.S.T.C.) (CCH)
American Federal Tax Reports (A.F.T.R.) (RIA)

Tax Citators

Citators are used to determine the subsequent history of a case, statute, or regulation, and thus assess its validity. While it is perfectly acceptable to use a general citator such as Shepard's (Lexis Advance) or KeyCite (Westlaw), there are specialized citators for federal tax research.

Federal Tax Citator 2d (RIA)
Cases are arranged by date and not citation, and they are also numbered to the headnoted issues in the American Federal Tax Reports. The citator is not cumulative, so it is necessary to check several volumes to update older cases. Coverage in the online version begins in 1954, so the print edition is required for checking cited references for older cases.
VitalLaw Tax Citator
Click the Document History icon in the left panel of any document to view the Citator details about the document. (See Working with VitalLaw Tax Citator below)

Court Rules and Forms

U.S. Tax Court Rules
U.S. Court of Federal Claims Rules
U.S. Tax Court Forms
U.S. Court of Federal Claims Forms

Abbreviations & Bluebook Rules

Selected Abbreviations:

American Federal Tax Reports, 2nd - A.F.T.R.2d (RIA)

Board of Tax Appeals Memorandum Decisions - B.T.A.M. or B.T.A. Mem. Dec.

Commissioner - Comm’r.

Reports of United States Board of Tax Appeals - B.T.A.

Reports of the United States Tax Courts - T.C.

Tax Court Memorandum Decisions - T.C.M. (RIA) or (CCH)

Tax Court Reported Decisions - Tax Ct. Rep. Dec. (RIA)

Tax Court Reporter - T.C.R. (CCH) or (RIA)
Treasury Regulation - Treas. Reg.

United States Tax Cases - U.S.T.C.

Bluebook Rules:

Bluebook Rule 12.9.1: Internal Revenue Code
Bluebook Table 1.2 (T1.2): Federal Administrative and Executive Materials: Department of the Treasury

Related Guides

Overview of the Regulations Process
(U.S. Internal Revenue Service)

Tax Law