AICPA Statements: Standards For Tax Services — Apply AICPA Statements On Standards For Tax Services

The practice of tax preparation and advisory services has long demanded a framework of professional accountability, yet for much of the twentieth century, CPAs operated without a unified set of ethical standards specifically governing tax work. While the AICPA's Code of Professional Conduct established broad ethical principles for the accounting profession, tax practitioners needed more granular guidance on issues such as the level of confidence required before signing a return, how to handle errors discovered in previously filed returns, and the extent to which a CPA could rely on information furnished by a client. The Statements on Standards for Tax Services (SSTSs) emerged to fill precisely this gap, creating enforceable professional standards that complement—but do not replace—federal and state tax law.

The central question these standards address is straightforward but profound: what duties does a CPA owe to the client, the tax system, and the public when preparing or advising on tax matters? The SSTSs answer this question by establishing minimum standards of conduct that are enforceable through the AICPA's disciplinary mechanisms, thereby protecting both taxpayers and the integrity of the voluntary compliance system on which U.S. taxation depends.

Before diving into the individual standards, it is essential to understand the foundational principles that undergird all seven SSTSs. These principles reflect a careful balancing act: the CPA serves as an advocate for the taxpayer within the legal boundaries of the tax system, while simultaneously maintaining professional integrity and promoting accurate reporting. The SSTSs do not require CPAs to act as auditors of their clients' information, nor do they require the CPA to resolve every ambiguity in favor of the government. Instead, they establish a reasonable basis standard that balances advocacy with professional responsibility.

The diagram above illustrates the architecture of the SSTSs framework. The first five standards—SSTS Nos. 1 through 5—deal with the affirmative obligations a CPA has when preparing tax returns and advising on tax positions. They address what level of confidence a position must meet (realistic possibility of being sustained), how to handle questions on returns, when estimates are permissible, and whether a CPA may depart from a position previously adopted. The final two standards—SSTS Nos. 6 and 7—address reactive obligations: what a CPA must do upon discovering an error or omission in a client's return or during an administrative proceeding. Together, the seven standards form a comprehensive code of conduct that is enforceable under the AICPA's disciplinary framework.

SSTS No. 1 — Tax Return Positions

SSTS No. 1 is the cornerstone of the entire framework. It establishes the minimum confidence level a CPA must have before recommending a tax return position or preparing a return that reflects such a position. Specifically, the standard requires that the CPA have a good-faith belief that the position has a realistic possibility of being sustained administratively or judicially on its merits if challenged. This threshold is generally interpreted to approximate a one-in-three (roughly 33%) likelihood of success, placing it above the 'frivolous' and 'not frivolous' thresholds but below the 'more likely than not' (greater than 50%) or 'substantial authority' benchmarks found in the Internal Revenue Code's penalty provisions. The standard further permits a CPA to recommend a position that does not meet the realistic possibility threshold provided the position is not frivolous and the CPA advises the taxpayer of the opportunity to avoid penalties by adequately disclosing the position on the return.

SSTS No. 2 — Answers to Questions on Returns

Tax returns frequently contain questions beyond mere numerical data—for example, whether a taxpayer has foreign bank accounts or has engaged in certain reportable transactions. SSTS No. 2 provides that a CPA should make a reasonable effort to obtain appropriate answers to all such questions. The CPA is not required to furnish an answer when the information is unavailable and the answer is not readily determinable, but the CPA should consider whether the omission could cause the return to be deemed incomplete or whether it could be construed as an attempt to mislead the taxing authority.

SSTS No. 3 — Certain Procedural Aspects of Preparing Returns

SSTS No. 3 addresses the CPA's right to rely on information furnished by the client without audit or verification, provided the CPA does not have reason to believe the information is incorrect or incomplete. This standard also addresses the use of information from prior-year returns: a CPA may use such data as a starting point but should make reasonable inquiries if the data appears inconsistent with the current year's circumstances. Importantly, SSTS No. 3 explicitly acknowledges that a CPA is not an auditor and is entitled to rely on the client's good-faith representations unless red flags are present.

SSTS No. 4 — Use of Estimates

In many situations, precise data is simply unavailable—a taxpayer may have lost receipts, or the exact mileage driven for business purposes may not have been tracked. SSTS No. 4 recognizes that the use of estimates is permissible when it is impractical to obtain exact data, provided that the estimates are reasonable and the CPA does not present them in a manner that implies greater accuracy than exists. The standard does not require the CPA to disclose on the return that an estimate was used, unless required by the taxing authority or unless the estimate is so imprecise that a reasonable person might view the return as misleading.

SSTS No. 5 — Departure from a Position Previously Concluded

Tax positions are not frozen in perpetuity. SSTS No. 5 provides that a CPA is not obligated to follow a position previously adopted for a taxpayer—whether from a prior year's return or an administrative proceeding—unless the taxpayer is bound by the earlier determination through a closing agreement or similar mechanism. Changes in legislation, new judicial precedent, or revised IRS guidance may all justify departing from a previously taken position.

SSTS Nos. 6 & 7 — Knowledge of Error

SSTS No. 6 addresses the discovery of errors or omissions during the preparation of a current-year return, while SSTS No. 7 addresses the same situation during an administrative proceeding (such as an audit or appeals conference). In both cases, the CPA must promptly advise the taxpayer of the error and recommend corrective action, which typically involves filing an amended return. However, the CPA is not permitted to unilaterally disclose the error to the IRS without the taxpayer's consent, reflecting the confidential nature of the CPA-client relationship. If the taxpayer refuses to take corrective action, the CPA should consider whether continued representation is appropriate and whether withdrawal from the engagement is warranted.

The flowchart above captures the critical decision logic of SSTS No. 1. In practice, a CPA's first inquiry is whether the proposed position has a realistic possibility of being sustained on its merits—approximately a one-in-three chance of success. If the answer is yes, the CPA may recommend the position without further qualification. If the answer is no, the CPA must determine whether the position is at least not frivolous. A frivolous position—one that is patently improper or has no basis in law—must be declined outright. For positions that fall between 'not frivolous' and 'realistic possibility,' the CPA may still prepare the return provided the taxpayer is advised of the opportunity to avoid penalties through adequate disclosure, typically using Form 8275 or Form 8275-R.

Consider the following scenario: CPA Sarah Chen is preparing the 2024 federal income tax return for her client, Marcus, a self-employed graphic designer. During the engagement, several issues arise that implicate different SSTSs. The worked example below walks through each issue and the standard it triggers.

A common source of confusion among CPA candidates is the relationship between the AICPA's SSTSs, Treasury Department Circular 230 (which regulates practice before the IRS), and the IRC penalty provisions (particularly §§ 6694 and 6662). While all three address the question of what standard a tax position must meet, they originate from different authorities, apply to different populations, and carry different consequences for non-compliance.

The SSTSs do not exist in isolation; they interrelate with broader ethical and regulatory frameworks that a CPA must navigate. Understanding how the SSTSs connect to the AICPA Code of Professional Conduct, state boards of accountancy rules, and federal tax law is essential both for the CPA exam and for real-world practice. The table below highlights the relationship between the SSTSs and more advanced regulatory structures.

On the CPA exam, the TCP section frequently tests candidates on scenario-based questions requiring application of the SSTSs. Candidates should be prepared to identify which specific SSTS applies to a given fact pattern, understand the CPA's obligations under that standard, and recognize the consequences of non-compliance. Exam questions often involve situations where the CPA must balance competing obligations—such as client advocacy versus the duty to recommend corrective action for a known error—and the correct answer requires precise knowledge of the relevant SSTS.