Technical Advice Memorandums (TAMs) are requested by IRS area offices after a return has been filed, often in conjunction with an ongoing examination. They are similar to private letter rulings, but whereas letter rulings come from a taxpayer's request for advice on a proposed transaction, TAMs arise from IRS employees' requests for advice regarding the examination of a tax return.
Authoritative Value:
"[A] technical advice memorandum to an area director, which relates to a particular case, should not be applied or relied upon as a precedent in the disposition of other cases. However, they provide insight with regard to the Service’s position on the law and serve as a guide" (IRM 4.10.7.2.9(3)).
TAMs issued after October 31, 1976 may be used as substantial authority to avoid the substantial understatement penalty.
Numbering:
TAMs share the same multiple digit file numbers with letter rulings, i.e. the first two digits indicating the year the TAM/Ruling was issued, the second two digits indicating the week of the year the TAM/Ruling was released, and the remaining numbers indicating the number of the item issued that particular week (e.g. T.A.M. 99-32-001 or P.L.R. 99-32-083). TAMs carry the first release numbers for any particular week.
Lexis Advance and Westlaw carry TAMs from 1954 - present.