Representation before the IRS · Legal Authority and References

Internal Revenue Code and income tax regulations

The Internal Revenue Code is the statute Congress enacted. Regulations are Treasury’s rules under it, and they come in three forms that a practitioner has to be able to tell apart, because they differ in how they were made, how long they last and how much weight they carry. Everything else on the authority list sits below these two, and the research habit that matters most is the plainest one: read the statute first.

The rule

Where the authority comes from. See the figures table (IRC § 7805(a)). Note the opening words: the Secretary’s rulemaking authority is general and residual — “except where such authority is expressly given by this title to any person other than an officer or employee of the Treasury Department.” Where a particular Code section instead directs the Secretary to prescribe regulations on a specific point, those are made under that specific grant rather than under § 7805(a).

How a regulation is made. See the figures table (Reg. § 601.601(a)(1)). Regulations and Treasury decisions are “prepared in the Office of the Chief Counsel,” approved by the Commissioner, then forwarded to the Secretary or delegate “for further consideration and final approval.”

Notice and comment. See the figures table (Reg. § 601.601(a)(2)). Where 5 U.S.C. § 553 requires it, general notice of proposed rules is published in the Federal Register, and the regulation sets out what that notice must contain. Reg. § 601.601 also carries detailed procedure for public hearings, including that oral comments “shall not be merely a restatement” of what was submitted in writing.

The three forms.

• A proposed regulation is the Service’s stated intention. It has been published for comment and has not been finalised.
• A temporary regulation takes effect immediately. See the figures table for the two rules that govern it (IRC § 7805(e)): it must also be issued as a proposed regulation, and it expires within 3 years of issuance.
• A final regulation is adopted by Treasury decision after the notice-and-comment process.

All three are authority. Reg. § 1.6662-4(d)(3)(iii) lists “proposed, temporary and final regulations construing such statutes” among the authorities for the substantial authority analysis. A proposed regulation is on the list even though it binds nobody.

Small business review. See the figures table (IRC § 7805(f)). A proposed or temporary regulation goes to the Chief Counsel for Advocacy of the Small Business Administration, who has 4 weeks to comment on its impact on small business, and those comments must be considered before a final regulation superseding it is prescribed.

Retroactivity. Regulations are governed by IRC § 7805(b)(1), which generally bars a temporary, proposed or final regulation from applying to a taxable period ending before the earliest of the date it was filed with the Federal Register, the date a related proposed or temporary regulation was so filed, or the date a notice substantially describing its expected contents was issued — subject to seven exceptions, including an 18-month window from enactment of the statute the regulation implements. That is a different rule from the one governing revenue rulings, which are retroactive by default.

Citation form tells you which is which. A regulation is numbered with the part first and the Code section it construes after — so Reg. § 1.6662-4 construes section 6662, in part 1. Part 1 is income tax, part 20 estate tax, part 25 gift tax, part 301 procedure and administration, part 601 the Statement of Procedural Rules. A T suffix marks a temporary regulation.

Current figures

How it works in practice

Read the statute before the regulation. The Code is what Congress enacted; the regulation is Treasury’s construction of it. Where the two appear to diverge, the divergence is the issue — and it is the whole ground of a Form 8275-R disclosure, which requires the position to represent a good-faith challenge to the validity of the regulation. A practitioner who only ever reads regulations will never see that question.

Know which grant a regulation was made under. A regulation issued under a specific grant in a Code section — where the statute directs the Secretary to prescribe regulations on that point — stands on firmer ground than one issued under the general authority of § 7805(a). The distinction has been the pivot of a great deal of litigation about regulatory validity, and a representative arguing that a regulation exceeds the statute should identify which kind it is.

A temporary regulation is on a clock. It expires within three years of issuance and must also have been issued as a proposed regulation. So a temporary regulation more than three years old has lapsed, and one that never appeared in proposed form was not properly issued. Both are worth checking before relying on — or before conceding — a temporary rule.

A proposed regulation binds nobody and is still authority. It cannot be enforced against a taxpayer and a taxpayer generally cannot be compelled to follow it. But it appears on the Reg. § 1.6662-4(d)(3)(iii) list, so it carries weight in the substantial authority analysis, and it is the clearest signal available of the position the Service intends to take. Treat it as evidence of direction, not as a rule.

Watch what a proposed regulation does to older guidance. Reg. § 1.6662-4(d)(3)(iii) provides that a private letter ruling is not authority if inconsistent with a subsequent proposed regulation. So a proposed regulation that binds nobody can still knock out a PLR a client was relying on.

The regulation number tells you the subject. Part 1 for income tax, 20 for estate, 25 for gift, 301 for procedure and administration, 601 for the procedural rules. When a citation looks unfamiliar, the part number places it before you read a word — and a T suffix means the three-year clock applies.

Do not carry the ruling retroactivity rule across. Revenue rulings are retroactive unless they say otherwise; regulations are prospective under § 7805(b)(1) unless an exception applies. Conflating them produces wrong advice on effective dates, and the 18-month exception is the one that most often makes a recent regulation reach back.

Procedural regulations are still regulations. Part 601 — the Statement of Procedural Rules — is where much of the material on rulings, examinations and practice before the IRS lives. It is not a publication and not an internal manual; it is codified in the Code of Federal Regulations, and its standards are current even where the offices it names have been restructured.

How this has changed

The three-year expiry on temporary regulations is a 1988 addition. IRC § 7805(e) was added by the Technical and Miscellaneous Revenue Act of 1988 and applies to regulations issued after 29 November 1988. Before it, a temporary regulation could sit unfinalised indefinitely, and some pre-1988 temporary regulations remain in force for that reason. So “temporary regulations expire in three years” is true of anything issued since 1988 and not of everything on the books.

Regulatory retroactivity was reversed in 1996. IRC § 7805(b) as it stood before the second Taxpayer Bill of Rights made regulations retroactive to the date of the statute unless the Secretary provided otherwise. The current § 7805(b)(1) starts from the opposite presumption. Material describing regulations as presumptively retroactive is pre-1996.

Small business review came in with the same Act. IRC § 7805(f) requires submission to the SBA’s Chief Counsel for Advocacy and consideration of the comments received. It is a procedural requirement on the Service and it occasionally matters to the validity of a regulation.

Reg. § 601.601’s institutional description is dated. It refers to the “Internal Revenue Code of 1954,” to sale of the Bulletin by the Superintendent of Documents, and to offices reorganised after the IRS Restructuring and Reform Act of 1998. The description of how regulations are prepared, approved and published is substantively current; the names around it are not.

Exam focus

Know that IRC § 7805(a) is the general rulemaking authority, and that many regulations are issued under a specific grant in the Code section they construe.

Know the three forms — proposed, temporary, final — and that all three are authority under Reg. § 1.6662-4(d)(3)(iii).

Know that a temporary regulation must also be issued as proposed and expires within 3 years (IRC § 7805(e)).

Know that regulations are prospective by default under IRC § 7805(b)(1), with the 18-month exception — the opposite of the default for revenue rulings.

Know the notice-and-comment requirement under 5 U.S.C. § 553 and what the Federal Register notice must contain.

Know the part numbers: 1 income tax, 20 estate, 25 gift, 301 procedure and administration, 601 Statement of Procedural Rules.

Check yourself

1. How long does a temporary regulation last? (A) Indefinitely, until finalised (B) One year (C) It expires within 3 years after the date of issuance (D) Until the next Treasury decision Answer: C. IRC § 7805(e)(2), which also requires that any temporary regulation be issued as a proposed regulation.

2. What weight does a proposed regulation carry? (A) The same as a final regulation (B) None at all (C) It binds no one, but is authority for the substantial authority analysis (D) It binds the IRS but not taxpayers Answer: C. Reg. § 1.6662-4(d)(3)(iii) lists proposed, temporary and final regulations.

3. A regulation is filed with the Federal Register in March 2026. May it apply to a taxable period ending in 2024? (A) Always — regulations are retroactive to the date of the statute (B) Generally not, unless an exception in IRC § 7805(b) applies (C) Only with the taxpayer’s consent (D) Only if it is a temporary regulation Answer: B. The exceptions include regulations filed or issued within 18 months of enactment of the statute, prevention of abuse, and correction of a procedural defect.

4. Reg. § 301.7605-1 belongs to which body of regulations? (A) Income tax (B) Estate tax (C) Procedure and administration (D) The Statement of Procedural Rules Answer: C. Part 1 is income tax, part 20 estate, part 25 gift, part 601 the Statement of Procedural Rules.

5. Under IRC § 7805(f), who reviews a proposed or temporary regulation for its impact on small business? (A) The Joint Committee on Taxation (B) The Chief Counsel for Advocacy of the Small Business Administration (C) The Taxpayer Advocate (D) The Office of Management and Budget Answer: B. Comments are due within 4 weeks and must be considered before a superseding final regulation is prescribed.