The IRS produces material that interprets and gives practical guidance to implement the Internal Revenue Code. While a great deal of this material is published weekly in the Internal Revenue Bulletin, some of the material is only available from unofficial or commercial services such as looseleaf, databases and the internet. 

Revenue rulings, the largest category, are prepared only by the Washington, DC office in response to individual taxpayer queries. They constitute the IRS’s application of tax law to a given set of facts and are applicable to all taxpayers. Since 1953, revenue rulings have been numbered consecutively by year and order number. For example, Rev. Rul. 75-105 indicates that it was issued in 1975 and was the 105th ruling that year.

Internal Revenue Bulletin (IRB) and Internal Revenue Cumulative Bulletin (CB)

Private letter rulings have been issued by regional district directors since 1976. These rulings are also responses to specific taxpayer queries, but are applicable only to the taxpayer seeking the ruling. They are numbered so that the first two digits represent the year of issuance, the next two the week of issuance and the last three digits the order number.

The full text of private letter rulings are not reprinted in any official source, as they have little precedential value.

Other IRS pronouncements include revenue procedures, which announce the administrative practices that will be followed by the IRS. Those revenue procedures that have general applicability may be added to the IRS Statement of Procedural Rules that is published in the CFR.