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Federal Tax Research Guide

A guide to conducting federal tax research.

Letter Rulings and Chief Counsel Advice

In addition to "IRB Guidance", the IRS regularly drafts other forms of administrative decision-making. They are not published in the Internal Revenue Bulletin.

Private Letter Rulings: 

A private letter ruling is the result of a request by a taxpayer to the Office of Chief Counsel for guidance on a proposed transaction. A PLR is binding only between the requesting taxpayer and the IRS. PLRs issued after October 31, 1976 may be considered as substantial authority.

Technical Advice Memoranda:

A Technical Advice Memorandum is issued either at the IRS's or the taxpayer's request for Chief Counsel guidance on a complex issue arising during the audit or examination of a particular taxpayer. A TAM is binding only on the particular taxpayer. TAMs issued after October 31, 1976 may be considered as substantial authority.

Chief Counsel Advice:

Chief Counsel Advice consists of memoranda written in response to various internal requests for guidance from IRS agents, officers, and attorneys. Chief Counsel Advice is not substantial authority and cannot be cited in court.

Finding Aids:


FTX-CCA (chief counsel advice); FTX-PLR (private letter rulings); FTX-TAM (technical advice memoranda); FTX-WD (all written determinations).


IRS Private Letter Rulings, IRS Technical Advice Memoranda databases.

"Agency Decisions" link leads to databases for all the different types of Chief Counsel Advice.

Miscellaneous IRS Material

IRS Forms and Publications: 

  • available directly from the IRS's website in pdf format.

The Internal Revenue Manual:

  • Guidelines for IRS employees, revenue agents & officers
  • Not binding on the IRS and does not confer substantive rights to taxpayers
  • Provides brief explanations of law and procedure

Available from the IRS's website:

Circular 230:

  • Ethical rules for tax practitioners and rules governing practice before the IRS
  • 31 C.F.R. part 10 ("Practice before the Internal Revenue Service")

Available from the IRS's website