You read a Revenue Ruling that supports your client's deduction, but a Tax Court decision goes the other way. Which one wins? The answer determines whether the position has substantial authority, and whether your client owes a 20% penalty.
Tax law is not one document. It is a stack of sources, written by different branches of government at different times, that sometimes agree and sometimes contradict. When sources conflict, the higher-ranking one controls. The hierarchy is the rulebook for that ranking.
You need this for two reasons. First, when you research a position, you have to know which source actually settles the question. Second, the §6662 accuracy-related penalty turns on whether the position has substantial authority, and that test counts only sources the IRS recognizes as authority.
The Internal Revenue Code is the federal tax statute, codified at Title 26 of the United States Code (USC). Congress writes it. The President signs it. It has the force of law. Nothing in the hierarchy outranks the Code.
Common mistakes
- Treating Revenue Rulings as binding on courts. Revenue Rulings bind the IRS in identical fact patterns. They do not bind any court. A taxpayer who relies on a Revenue Ruling against contrary regulation guidance will lose in litigation. Trap: an answer choice stating that a Revenue Ruling "controls" or "binds the Tax Court" is wrong.
- Citing a PLR as authority for a different taxpayer. A PLR binds the IRS only as to the requesting taxpayer. Practitioners researching positions can read PLRs to predict IRS thinking, but cannot use them in a §6662 substantial-authority analysis. Trap: a choice describing a PLR as "substantial authority" for any taxpayer who reads it.
- Ranking a Tax Court Memorandum decision as equal to a Tax Court Regular decision. Memorandum decisions apply settled law to new facts; Regular decisions establish precedent. Memo decisions are persuasive, not precedential. Trap: a question listing both T.C. and T.C. Memo and asking which controls, Regular controls.
Bottom line
- Statutory sources (Internal Revenue Code, Title 26 USC, and ratified tax treaties) are the highest tier and carry the force of law.
- Treasury Regulations rank below the Code: legislative outrank interpretive outrank procedural, and final outranks temporary outranks proposed.
- Judicial hierarchy runs Supreme Court, then Circuit Courts, then trial courts (Tax Court Regular, District Court, Court of Federal Claims), then Tax Court Memorandum.
- IRS pronouncements (Revenue Rulings, Revenue Procedures, Notices) bind the IRS but not courts; PLRs and TAMs bind only the requesting taxpayer.
Exam shortcut
When a question lists conflicting sources and asks "which controls?", walk down the hierarchy: Code first, then final Treasury Regs, then court decisions in your circuit, then Revenue Rulings and Notices. PLRs and TAMs almost never "control" anything for a third-party taxpayer, they're the trap answer. C-R-J-A for the four tiers: Code, Regulations, Judicial, Administrative pronouncements (Revenue Rulings, Notices, PLRs). "Final beats Temp beats Proposed" for regulations.
The full lesson (about 3,028 words, 20 min read) adds 2 worked examples, all 6 common mistakes, a self-check, free in the app.
Learning objectives
- I.C4
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