Authoritative Hierarchy and Tax Return Position Standards |...

SECTION 1

Historical Context & Motivation

As the federal tax system grew from a single constitutional amendment into a vast body of statutes, regulations, and case law, CPAs faced a practical problem: with so many sources of tax law — some binding, some merely persuasive, and some in direct conflict — how much support is enough before recommending a position to a client? Without a clear way to rank sources of authority, practitioners had no consistent method for deciding whether a deduction, credit, or election was defensible enough to report on a return.

Over time, Congress, the Treasury Department, the IRS, and the federal courts each contributed layers to this body of law, and the accounting profession developed a working hierarchy of authority to sort through it. As guidance multiplied — statutes, regulations, revenue rulings, private letter rulings, and court decisions — the profession also developed defined confidence-level standards, such as substantial authority and more likely than not, that tell a practitioner how much support is needed before a position can be taken, with or without disclosure.

1913

16th Amendment Ratified

Ratification of the Sixteenth Amendment gave Congress constitutional authority to levy an income tax without apportionment among the states. This amendment is the ultimate source of everything that follows in the hierarchy of tax authority — statutes, regulations, and case law.

1939

First Codification: Internal Revenue Code of 1939

Congress consolidated decades of scattered revenue acts into a single codified body of law. This first Internal Revenue Code gave practitioners one primary statutory source to consult rather than dozens of separate acts.

1954

Internal Revenue Code of 1954

A comprehensive recodification reorganized federal tax statutes into the section-numbering structure still recognizable in today's Code, and expanded Treasury's authority to issue interpretive regulations — adding a second major layer to the hierarchy of authority.

1986

Tax Reform Act of 1986

Sweeping legislative reform renamed the statute the Internal Revenue Code of 1986 and introduced significant changes to individual and corporate taxation. The Act also expanded the volume of administrative guidance — revenue rulings, revenue procedures, and notices — that practitioners must weigh alongside the statute and regulations.

1998

IRS Restructuring and Reform Act

This Act reorganized the IRS and strengthened taxpayer procedural protections, underscoring the growing importance of understanding not just what the law says, but how confidently a position can be supported if it is challenged on examination.

2017

Tax Cuts and Jobs Act

Substantial changes to individual and business tax provisions triggered a wave of new Treasury regulations, IRS notices, and other subregulatory guidance. Tax professionals must continually rank and reconcile this expanding body of authority within the hierarchy described in this lesson.

The central question this lesson addresses is both simple and consequential: how much authoritative support does a CPA need before recommending a tax return position to a client, and does that position need to be disclosed? Understanding the hierarchy of tax authority — and the confidence-level standards built on top of it — is essential for any CPA engaged in tax compliance, planning, or research.

SECTION 2

Core Principles & Definitions

Before examining the specific confidence-level standards, it is essential to understand the sources of tax law that CPAs consult and how those sources are ranked. Tax authority is generally divided into two categories: primary authority — issued directly by the legislative, executive, or judicial branches of government — and secondary authority — commentary, treatises, and other unofficial interpretive materials that explain or summarize primary authority but carry no independent legal force.

Statutory Authority (The Internal Revenue Code)

The Internal Revenue Code (IRC), enacted by Congress, is the highest-ranking source of federal tax law. Every regulation, ruling, and court decision must ultimately be consistent with the statutory language Congress has enacted.

Treasury Regulations

Regulations are issued by the Treasury Department to interpret and implement the Code. Final regulations generally carry substantial weight, proposed regulations are not yet binding, and temporary regulations have the force of law for a limited period while a permanent rule is finalized.

Administrative Guidance

The IRS also issues revenue rulings, revenue procedures, notices, and private letter rulings. Revenue rulings and procedures generally apply to all taxpayers, while private letter rulings bind only the taxpayer who requested them, though practitioners may still find them informative.

Judicial Authority

Federal courts — the U.S. Tax Court, U.S. District Courts, the Court of Federal Claims, and the Courts of Appeals — interpret and apply the Code to specific facts. A decision's weight depends on factors such as the level of the court and whether the IRS has acquiesced in the outcome.

Secondary Authority

Treatises, tax journal articles, and commercial tax services summarize and analyze primary authority. Secondary sources can help a CPA locate and understand primary authority, but they cannot, by themselves, support a tax return position.

✦ KEY TAKEAWAY

Think of the hierarchy of tax authority like a corporate organizational chart. The Internal Revenue Code sits at the top, like a board of directors setting the ultimate rules. Treasury Regulations function like an executive team translating those directives into operating policy. Revenue rulings and IRS notices are like department memos applying policy to specific situations. Secondary sources — treatises and articles — are like industry newsletters: useful for understanding the landscape, but they don't set policy themselves.

SECTION 3

Visual Overview of the Tax Authority Confidence Framework

The following diagram illustrates how the three primary confidence-level standards relate to their governing Code sections, the party they protect, and whether disclosure is required. Understanding this architecture is foundational: Reasonable Basis is the lowest tier and generally requires disclosure, while Substantial Authority and More Likely Than Not are progressively stronger standards that do not require disclosure. The diagram below maps each standard to its governing Code section, threshold, and the party it protects.

Reasonable Basis is the lowest tier and generally requires disclosure to protect a taxpayer. Substantial Authority and More Likely Than Not are progressively stronger standards that do not require disclosure to avoid the general accuracy-related and preparer penalties. More Likely Than Not is reserved for tax shelters and reportable transactions, where it applies to both taxpayers and preparers regardless of disclosure; for ordinary undisclosed positions, preparers generally rely on the same substantial authority standard that protects the taxpayer.

As the diagram makes clear, Reasonable Basis is the weakest standard and, on its own, does not shield a taxpayer from the accuracy-related penalty — it must be paired with disclosure. Substantial Authority and More Likely Than Not are both stronger, objective-style standards that do not require disclosure, with More Likely Than Not representing the highest bar. The practical implication for CPA practitioners is that, for most return positions, both the taxpayer's accuracy-related penalty risk under IRC §6662 and the preparer's penalty risk under IRC §6694 are measured against the same substantial authority standard for undisclosed positions; only tax shelters and reportable transactions require the higher more-likely-than-not standard under §6694, regardless of disclosure.

SECTION 4

How CPAs Apply the Framework — The Tax Research Process

Applying the hierarchy of authority is not a mechanical calculation, but it does follow a repeatable process that CPAs use to move from an open tax question to a documented, defensible conclusion. This section walks through that process, phase by phase.

Phase 1: Identify the Issue and Gather the Facts

The CPA begins by clearly defining the tax question and gathering the relevant facts — the nature of the transaction, the entities involved, amounts, and timing. A precisely framed issue keeps the subsequent research focused and prevents wasted effort chasing authority that does not actually apply to the client's facts.

Phase 2: Locate and Analyze Primary Authority

The CPA searches the Internal Revenue Code, applicable Treasury Regulations, IRS rulings and procedures, and relevant case law. Secondary sources — treatises, tax services, and journal articles — are often useful at this stage to help locate primary authority and understand how others have analyzed similar issues, even though they cannot independently support the position.

Phase 3: Weigh the Authority

Not all authority carries equal weight. A statute outranks a regulation, a final regulation outranks a proposed one, and a directly on-point court decision from a court with jurisdiction over the taxpayer generally carries more weight than a ruling addressing similar but distinguishable facts. When authorities conflict, the CPA must assess which side is better supported, more recent, and more directly on point.

Phase 4: Determine the Confidence Level and Recommend a Position

Based on the weight of authority gathered, the CPA determines whether the position satisfies Reasonable Basis, Substantial Authority, or More Likely Than Not. This determination drives the recommendation: whether the position can be taken without disclosure, whether disclosure is advisable to fall back on a lower standard, or whether the position should not be taken at all. The full analysis is documented in a tax research memorandum.

The research process flows from issue identification through recommendation. A tax research memo typically includes all four sections shown above. Sources consulted include the Code, Treasury Regulations, IRS rulings, and case law — with the Code carrying the greatest authoritative weight.

SECTION 5

Confidence-Level Standards for Tax Return Positions

Once the relevant authority has been located and weighed, the CPA must classify the position according to a defined confidence-level standard. These standards, developed within the accounting and tax profession and reflected in the Internal Revenue Code, tell a practitioner how much support is needed before a position may be taken, and whether disclosure is required. Understanding these standards is critical for CPA candidates, because the standard that applies directly determines whether disclosure is necessary and who bears potential penalty exposure.

Confidence-Level Standards Used to Evaluate Tax Return Positions

Standard	Definition	Example Context	Typical Application
Not Frivolous (Minimum Threshold)	A position that has some plausible basis in the law, even if weak. This is the lowest threshold recognized in tax practice and is generally insufficient on its own to avoid penalties.	Citing an ambiguous, isolated statutory phrase without other supporting authority	Rarely relied on alone as a stand-alone standard for CPA-prepared returns
Reasonable Basis	A reasonably arguable, good-faith position in the law — meaningfully higher than 'not frivolous,' though weaker than substantial authority.	One supporting private letter ruling issued to a different taxpayer, combined with a plausible reading of the statute	Sufficient for taxpayers only when the position is disclosed on the return (e.g., Form 8275)
Substantial Authority	An objective standard met when the weight of authorities supporting the position is substantial in relation to the weight of authorities supporting a contrary position.	A revenue ruling and a Tax Court decision supporting the position, with only a single, older private letter ruling on the other side	Protects the taxpayer from the accuracy-related understatement penalty without requiring disclosure, and is also the general standard preparers must meet for undisclosed positions under IRC §6694(a)
More Likely Than Not (MLTN)	The position is supported by authority indicating a greater than 50% likelihood of being upheld if challenged and litigated on the merits.	A directly on-point, unreversed appellate decision in the taxpayer's jurisdiction, with no significant contrary authority	Required under IRC §6694(a) specifically for tax shelter and reportable transaction positions, regardless of disclosure — not the general standard for ordinary undisclosed positions

The Substantial Authority standard often functions as the practical dividing line in practice: positions that clear this bar can generally be taken without disclosure, while positions that fall short typically require disclosure — paired with at least a reasonable basis — to avoid penalty exposure. For most return positions, the preparer's own standard under IRC §6694 mirrors the taxpayer's: substantial authority for undisclosed positions, or reasonable basis paired with disclosure. The more likely than not standard under §6694 is reserved for tax shelters and reportable transactions, where it applies regardless of disclosure.

Confidence-Level Spectrum — From Minimal to High Certainty

Not Frivolous

Reasonable Basis

Substantial Authority

More Likely Than Not

Minimal ConfidenceHigh Confidence

SECTION 6

Worked Example — Evaluating a Tax Return Position

Consider the following scenario: Meridian Manufacturing Co. wants to claim a $2 million research credit under IRC §41 for costs incurred developing a new production process. The CPA's research uncovers one favorable Tax Court memorandum decision on closely similar facts, but also a Revenue Ruling reaching a different conclusion, with no Circuit Court precedent directly on point. This worked example walks through the decision-making process for determining the applicable confidence standard and whether disclosure is warranted.

Determining the Confidence Level for Meridian Manufacturing's Research Credit Position

Step 1 — Identify the Position and Gather the FactsMeridian's research activities involve developing a new production process, and the costs at issue appear to meet the general definition of qualified research expenditures. The CPA documents the facts: the nature of the research, the amounts spent, and the specific technical uncertainty the project addressed, since these facts will determine which authorities are actually relevant.

Position identified: a $2 million research credit claim under IRC §41

Step 2 — Locate and Weigh the Available AuthorityThe CPA's research turns up a favorable, unreversed Tax Court memorandum decision addressing closely similar facts, but also an IRS Revenue Ruling reaching a contrary conclusion. No Circuit Court decision directly addresses the issue, leaving the authority genuinely split between one primary source favoring the position and one opposing it.

Authority is split: one supporting Tax Court memorandum decision versus one contrary Revenue Ruling

Step 3 — Determine Whether Substantial Authority ExistsBecause Tax Court memorandum decisions generally carry less precedential weight than a regular Tax Court opinion, and the IRS has already taken a contrary position in a published ruling, the CPA cannot confidently conclude that the weight of authority substantially favors Meridian's position. The reasonable basis standard, however, is clearly satisfied given the existence of a favorable court decision.

Conclusion: uncertain whether substantial authority is met; reasonable basis is clearly met

Step 4 — Decide Whether Disclosure Is WarrantedGiven the uncertainty around substantial authority, the CPA recommends that Meridian disclose the position on Form 8275. Disclosure allows the taxpayer to rely on the lower reasonable basis standard to avoid the accuracy-related penalty, rather than depending on a substantial authority determination the CPA is not fully confident in.

Recommendation: disclose the position on Form 8275 to rely on the reasonable basis standard

Step 5 — Confirm the Preparer's Reporting PositionBecause the position will be disclosed, the preparer can rely on the reasonable basis standard rather than needing to determine whether substantial authority is independently satisfied under IRC §6694. The research credit claim is not a tax shelter or reportable transaction, so the higher more-likely-than-not standard does not come into play here. This closes the loop between the taxpayer's penalty protection and the preparer's own penalty protection, both of which are addressed by the same disclosure decision.

Conclusion: with disclosure and reasonable basis, both taxpayer and preparer penalty exposure is mitigated

SECTION 7

Comparing Confidence-Level Standards — Strengths and Limitations

Each confidence-level standard serves a distinct purpose, and misjudging which standard applies can leave a client or preparer exposed to penalties. The following table compares the three main standards across multiple dimensions, enabling CPA practitioners to make informed decisions about disclosure and reporting.

Comparative Analysis of Reasonable Basis, Substantial Authority, and More Likely Than Not

Dimension	Reasonable Basis	Substantial Authority	More Likely Than Not
Governing Code Section	IRC §6662(c)	IRC §6662(d)	IRC §6694(a) (tax shelters/reportable transactions)
Threshold	Reasonably arguable, good-faith position	Weight of authority substantially favors the position	Greater than 50% likelihood of success on the merits
Disclosure Requirement	Required	Not required	Not required (disclosure allows a lower reasonable-basis standard instead)
Applies To	Taxpayer (negligence penalty); also the preparer standard for disclosed positions under §6694(a)	Taxpayer (understatement penalty); also the general preparer standard for undisclosed positions under §6694(a)	Taxpayer and preparer, specifically for tax shelters and reportable transactions
Primary Use Case	Positions with limited support that the client still wants to disclose and take	Positions with meaningful, but not overwhelming, support	Tax shelter and reportable transaction positions, which require this heightened standard regardless of disclosure
Key Limitation	Alone, does not protect against the understatement penalty	A subjective, fact-intensive judgment call that can be difficult to document with precision	The highest bar — many defensible positions fall short of a true majority-confidence likelihood

✦ KEY TAKEAWAY

Think of these standards like a weather forecaster's confidence in a storm forecast. Reasonable basis is like saying there's some chance of rain — worth mentioning, but not something you'd bet on without a caveat. Substantial authority is like a forecaster whose models mostly agree a storm is coming — a meaningfully confident call, even if not certain. More likely than not is like a forecaster confident enough to guarantee rain without hedging — a majority-confidence call that the tax law reserves for its highest-scrutiny situations, such as tax shelters and reportable transactions.

SECTION 8

Emerging Issues in Tax Authority and Practitioner Standards

The hierarchy of tax authority and its confidence-level standards continue to matter as new categories of transactions and disclosure obligations emerge. Two areas in particular require CPAs to apply the same underlying framework to more complex fact patterns.

Ordinary Positions vs. Higher-Scrutiny Reporting Contexts

Dimension	Ordinary Positions	Reportable Transactions	Cross-Border Positions
Typical Context	Most day-to-day return positions — deductions, credits, and elections	Listed or reportable transactions the IRS has identified as having potential for tax avoidance	Positions involving multinational entities, treaties, or transfer pricing
Focus	Applying the ordinary confidence-level standards described in this lesson	Additional disclosure obligations often exist even when a position is otherwise well supported	Layered authority — treaties, competent authority guidance, and multiple countries' rules may all be relevant
Confidence Standard	Reasonable basis through substantial authority, depending on disclosure	Often requires the more likely than not standard under IRC §6694, applicable regardless of disclosure, with additional disclosure obligations that can apply even when the position is otherwise well supported	May require reliance on secondary sources, such as treaty commentary, as persuasive but non-binding guidance
CPA Relevance	Core competency tested within REG's Ethics, Professional Responsibilities, and Federal Tax Procedures area	Growing area of practice as the IRS continues to identify new categories of transactions requiring disclosure	Increasingly relevant for CPAs advising clients with cross-border operations or investments

⚠️ CPA Exam Alert

The REG section may test your ability to distinguish between reasonable basis, substantial authority, and more likely than not, determine when disclosure (such as Form 8275) is necessary to avoid a penalty, and identify the difference between the accuracy-related penalty under IRC §6662 and the return preparer penalty under IRC §6694. Be prepared to evaluate conflicting authorities and determine which standard a given fact pattern satisfies — and remember that more likely than not is reserved for tax shelters and reportable transactions, not the general undisclosed-position standard.

Looking ahead, as tax law continues to address emerging areas such as digital assets, cryptocurrency transactions, and complex cross-border arrangements, CPAs increasingly encounter situations where formal regulations lag behind the underlying transactions. In these gaps, practitioners often must rely more heavily on notices, proposed regulations, and analogous guidance — carefully weighing their relative authority — until the IRS and Treasury issue more definitive rules. For CPA candidates and practitioners, this reinforces why understanding the hierarchy of authority itself, rather than memorizing any single rule, is the durable skill tested throughout REG's Ethics, Professional Responsibilities, and Federal Tax Procedures area.

SECTION 9

Practice Problems

PROBLEM 1 — CONCEPTUAL

A CPA is preparing an individual's tax return and identifies a deduction position that has only a reasonable basis — not substantial authority — under current guidance. What must the CPA do to help the client avoid the accuracy-related penalty under IRC §6662, and why does disclosure matter in this situation?

PROBLEM 2 — BASIC CALCULATION

An individual taxpayer's return should have shown a tax liability of $70,000, but the taxpayer actually reported and paid only $61,800, resulting in an $8,200 understatement discovered on audit. Applying the rule that an individual's understatement is 'substantial' under IRC §6662 if it exceeds the greater of 10% of the tax required to be shown on the return or $5,000, determine whether this understatement is substantial.

PROBLEM 3 — INTERMEDIATE

A tax research memo cites a leading tax treatise's interpretation of an ambiguous Code section, along with a Revenue Ruling that reaches a different conclusion. Explain which source constitutes primary authority and which constitutes secondary authority, and describe how a CPA should use each in supporting a return position.

PROBLEM 4 — APPLIED

A CPA researching a client's like-kind exchange question finds: (1) the relevant Internal Revenue Code section, (2) a final Treasury Regulation interpreting that section, (3) a private letter ruling issued to a different, unrelated taxpayer reaching a favorable conclusion on similar facts, and (4) a tax journal article discussing planning strategies in this area. Rank these four sources from highest to lowest authoritative weight and explain the reasoning.

PROBLEM 5 — CRITICAL THINKING

A tax return preparer is evaluating an undisclosed position that is not a tax shelter or reportable transaction. The available authority clearly satisfies the reasonable basis standard and, in the preparer's judgment, also satisfies substantial authority, though the preparer is not confident it would reach a more-likely-than-not level of support if litigated. Analyze whether the preparer can sign the return without disclosure, and explain how the analysis would differ if the position instead involved a tax shelter or reportable transaction.

SUMMARY

Lesson Summary

CPAs evaluate proposed tax return positions using a hierarchy of authority and a corresponding set of confidence-level standards. Primary authority — the Internal Revenue Code, Treasury Regulations, IRS rulings and procedures, and judicial decisions — carries legal weight, while secondary authority such as treatises and journal articles is useful for research but cannot independently support a position. Three standards define how much support is enough: Reasonable Basis (the lowest tier, generally requiring disclosure), Substantial Authority (a stronger, objective standard that protects a taxpayer without disclosure, and is also the general preparer standard for undisclosed positions), and More Likely Than Not (a greater-than-50% likelihood of success, required under IRC §6694 specifically for tax shelters and reportable transactions, regardless of disclosure).

Key concepts for CPA practitioners include the role of the tax research memorandum in documenting facts, issues, authority, and conclusions; the distinction between the accuracy-related penalty under IRC §6662 (which addresses taxpayer exposure) and the return preparer penalty under IRC §6694 (which addresses preparer exposure, generally at the same substantial authority level as the taxpayer for undisclosed positions); and the importance of disclosure, such as Form 8275, in lowering the standard a position must meet. Emerging areas such as reportable transactions and cross-border tax questions continue to test a CPA's ability to weigh conflicting or incomplete authority — reinforcing that understanding the hierarchy itself, not just individual rules, is the durable skill for tax compliance and planning.