Tax Research - Federal Guide

This guide on federal tax research explains where and how to find tax materials.

Internal Revenue Bulletin Guidance

Revenue Ruling (Rev. Rul.)

A Revenue Ruling is an official interpretation by the IRS of the Code, related statutes, tax treaties, and regulations. It explains the IRS's position on how the law is applied to a specific set of facts. 

Any taxpayer whose circumstances are substantially the same as those described in the Ruling can rely on it.

Revenue Procedure (Rev. Proc.)

A Revenue Procedure is an official statement of a procedure that affects the rights or duties of taxpayers under the Code, related statutes, regulations, and treaties that should be a matter of public knowledge. Generally, it provides instructions for return filing or other procedures. Sometimes it may have a substantive effect (e.g., interest rate tables).


Notices provide interim guidance before finalized revenue rulings and regulations are available.

Announcements (Ann.) 

Announcements are public pronouncements that have only immediate or short-term value (e.g., extension of filing deadlines for areas hit by natural disasters).

Finding IRB Guidance

The Internal Revenue Bulletin (I.R.B.) is published weekly and compiled semi-annually into the Cumulative Bulletin (C.B.). Note that the C.B. ceased publication in 2008.

Specialized Tax Databases

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