Representation before the IRS · Power of Attorney

Purpose of a Centralized Authorization File (CAF) number

The Centralized Authorization File is a database and the number is a filing key. Neither confers anything. The regulation is unusually explicit on that point, and equally explicit about the limits on what the system records — limits that catch practitioners who assume a filed authorisation is a recorded one.

The rule

What the CAF holds (Reg. § 601.506(d)(1)). Information from both powers of attorney and tax information authorizations is recorded. That information lets IRS personnel who do not have the actual document determine whether a recognized representative or appointee is authorised to receive and inspect confidential tax information; determine whether a representative is authorised to perform the acts set out in Reg. § 601.504(a); and send copies of computer-generated notices and communications to the person so authorised.

The number (Reg. § 601.506(d)(2)). A CAF number generally issues to a recognized representative who files a power of attorney and a written declaration of representative, or to an appointee authorised under a tax information authorization.

The regulation then states the point plainly: “The issuance of a CAF number does not indicate that a person is either recognized or authorized to practice before the Internal Revenue Service.” That is determined under Circular 230. The number’s purpose is to facilitate processing, and a representative should include the same number on every authorisation filed — but because it is not a substantive requirement under Reg. § 601.503(a), an authorisation will not be rejected for its absence.

What gets recorded (Reg. § 601.506(d)(3)). Although a power of attorney or tax information authorization may be filed in all matters under IRS jurisdiction, only documents meeting each of the following criteria are recorded:

1. Specific tax period. Only documents concerning a matter relating to a specific tax period are recorded — the regulation’s examples of matters that cannot be are the IRC § 6672 penalty, EIN applications, and private letter ruling requests on a proposed transaction.
2. Future three-year limitation. Only documents concerning a tax period ending no later than three years after the date the power of attorney is received by the IRS are recorded. The current Form 2848 instructions measure this differently and more generously — see “How this has changed” below.
3. Prior tax periods. Documents concerning a tax period that ended before the power of attorney is received are recorded, provided matters concerning those years are under consideration by the IRS.
4. Three-representative limit. No more than three representatives under a power of attorney, or three persons under a tax information authorization, are recorded. Where more are named, only the first three are recorded.

And the closing sentence: the fact that a document cannot be recorded is not determinative of its current or future validity. Documents reaching beyond the horizon are not invalid for the unrecorded periods — they can be resubmitted later.

Current figures

How it works in practice

The number is not a credential. The regulation supplies the point in terms: issuance of a CAF number does not indicate that a person is recognized or authorized to practise. Eligibility comes from Circular 230. An unenrolled appointee under a Form 8821 holds a CAF number and may practise before the IRS not at all.

Nor is it a filing requirement. Reg. § 601.503(a) lists the substantive requirements of a power of attorney; the CAF number is not among them. An authorisation without one is processed, not rejected. What the regulation asks is consistency: the same number on every authorisation.

“Recorded” and “valid” are different states, and the closing sentence of § 601.506(d)(3) makes that explicit. The forward horizon limits the database, not the authorisation. A Form 2848 covering periods five years out is a good power of attorney for them; it simply will not sit in the CAF until resubmitted closer to the time.

The specific-period rule, read with the current instructions. The 1991 regulation names the IRC § 6672 trust fund recovery penalty as unrecordable. The current Form 2848 instructions describe a specific-use power of attorney — a one-time or specific-issue grant, or one not relating to a specific tax period — as not recorded, and expressly except civil penalties, listing instead private letter ruling and technical advice requests, EIN and ITIN applications, Form 843 claims, corporate dissolutions, Circular 230 disciplinary proceedings, accounting method and period changes, and exemption and plan determination applications. On the trust fund recovery penalty the instructions are the better guide. Either way the authorisation is effective; the CAF question is only whether IRS personnel see it without being shown the document.

The three-representative limit is a recording limit too. Naming five representatives does not invalidate the fourth and fifth appointments; it means the CAF carries the first three. Where that matters is notices: § 601.506(d)(1)(iii) makes the CAF the mechanism for sending copies of computer-generated notices, so a representative outside the recorded three will not receive them automatically. Order the names deliberately.

Prior periods are conditional. A power of attorney for a closed year is recorded only if matters concerning that year are under IRS consideration.

Recording also decides how far a revocation reaches. Line 6 of the Form 2848 instructions ties revocation to the CAF: a recorded power generally revokes any earlier power previously recorded for the same matter, while a specific-use or unrecorded power revokes only an earlier one on file with the same office for the same matters. Filing a Form 2848 does not revoke a Form 8821.

How this has changed

Section 601.506 was published at 56 FR 24008 on May 28, 1991, and has not been amended since. That vintage shows in three places, and none of them changes the substance.

First — and this is a substantive divergence, not a cosmetic one — the forward horizon is stated differently in the current instructions. Reg. § 601.506(d)(3)(ii) measures three years from the date the power of attorney is received, and illustrates it with a worked example running from 1 August 1990 to 31 July 1993. The Instructions for Form 2848 (rev. 09/2021, page last reviewed 30 April 2026) instead say the IRS will not record future periods “that exceed 3 years from December 31 of the year that the IRS receives the power of attorney.” That is more generous, and it is the rule the IRS actually applies. A power of attorney received in March 2026 reaches periods ending through 31 December 2029 under the instructions, but only through March 2029 on the face of the regulation. Follow the instructions; the regulation’s worked example predates them by three decades.

Second, the neighbouring § 601.506(b)(2) still refers a bypassed representative to the “Director of Practice” for possible disciplinary proceedings. That office became the Office of Professional Responsibility in 2003. The mechanism survives; the name does not.

Third, the section was written for paper filing. The IRS has since built electronic submission routes prescribed in forms and instructions rather than in Part 601 — the instructions now point to the Tax Pro Account, where most requests record immediately. Those channels change how a document reaches the CAF, not what it records.

Worth noting alongside the CAF rules, because they sit in the same section: § 601.506(c) provides that a Treasury check is mailed to a recognized representative only where the power of attorney contains specific authorization, and that where more than one representative is so authorised at different addresses, the IRS mails the check directly to the taxpayer unless all sign a statement giving one address. That is a delivery rule; Circular 230 § 10.31 separately forbids a practitioner to endorse or negotiate the check.

Exam focus

The most tested fact is that a CAF number confers nothing — not practice authority, not recognition. It is a processing key, and Circular 230 governs eligibility.

Know the four recording criteria: a specific tax period; the three-year forward horizon — measured by the current instructions from 31 December of the year of receipt, not from the date; prior periods only where under IRS consideration; and no more than three representatives.

Know that failure to record does not invalidate the authorisation, and that the document may be resubmitted later for periods beyond the horizon.

Know that the CAF holds both powers of attorney and tax information authorizations, and is the route for copies of computer-generated notices.

Check yourself

1. What does issuance of a CAF number establish about the holder? (A) That the holder may practise before the IRS (B) That the holder is a Circular 230 practitioner (C) Nothing about eligibility; it facilitates processing of the authorisation (D) That the holder may receive Treasury checks Answer: C. Reg. § 601.506(d)(2) — issuance does not indicate that a person is either recognized or authorized to practise; that is determined under Circular 230.

2. A power of attorney received by the IRS in June 2026 covers tax periods through 2033. What is recorded on the CAF? (A) All periods listed (B) Periods ending no later than 31 December 2029 (C) No periods, because the document spans more than three years (D) Only periods that have already ended Answer: B. The Form 2848 instructions bar recording future periods exceeding 3 years from 31 December of the year of receipt. Reg. § 601.506(d)(3)(ii) measures from the date of receipt; the instructions govern in practice. Either way the document stays valid for the rest and may be resubmitted.

3. A Form 2848 names four representatives. What follows? (A) The form is rejected (B) All four are recorded (C) The first three are recorded; all four remain appointed (D) The taxpayer must choose three Answer: C. Reg. § 601.506(d)(3)(iv) records no more than three and, where more are named, only the first three. The recording limit does not undo the appointments.

4. Which is a “specific use” matter the IRS does not record on the CAF? (A) A 2025 individual income tax examination (B) A request for a private letter ruling (C) A 2024 employment tax matter under consideration (D) A 2026 individual income tax matter Answer: B. The Form 2848 instructions list private letter ruling and technical advice requests among specific uses not recorded, along with EIN and ITIN applications, Form 843 claims, corporate dissolutions and Circular 230 disciplinary proceedings — a power of attorney not relating to a specific tax period, except for civil penalties.

5. Is an authorisation rejected if the representative omits a CAF number? (A) Yes, it is a substantive requirement (B) Yes, unless the representative has never been issued one (C) No, the CAF number is not among the substantive requirements of Reg. § 601.503(a) (D) No, but only for tax information authorizations Answer: C. Reg. § 601.506(d)(2) says a document will not be rejected based on the absence of a CAF number, because the number is not a substantive requirement.