PCAOB Rule 3526 requires registered public accounting firms to communicate specific independence-related information to audit committees before accepting an initial PCAOB audit engagement and at least annually during continuing engagements. For public companies, this is a practical governance safeguard—not merely a letter to collect before an SEC filing.

The rule matters whenever an audit committee is appointing an auditor, assessing non-audit services, evaluating relationships involving executives, or responding to a potential independence violation. This guide explains the written disclosures, discussions, annual affirmation, documentation expectations, and the 2019 PCAOB staff guidance, then provides a usable checklist and sample communication framework.

What Is PCAOB Rule 3526?

Rule 3526, “Communication with Audit Committees Concerning Independence,” is part of the PCAOB ethics and independence rules. It applies to registered public accounting firms accepting an initial engagement under PCAOB standards and to ongoing audit clients covered by the rule. Its aim is to give those charged with audit oversight information about relationships that may reasonably be thought to affect an auditor’s independence.

Rule 3526 does not by itself make a prohibited relationship acceptable. PCAOB Rule 3520, SEC Regulation S-X Rule 2-01, and other applicable restrictions determine whether the firm is independent. Rule 3526 establishes important disclosure and discussion obligations alongside that substantive assessment.

Why the Audit Committee Needs More Than a Generic Independence Letter

The committee must understand both the existence of relevant relationships and their potential effect on objectivity. A boilerplate assertion with no meaningful consideration of affiliate relationships, historical non-audit work, or relevant personnel circumstances may not provide adequate oversight information.

For the broader framework, read MBP Global’s PCAOB Independence Rules guide.

Rule 3526(a) vs. Rule 3526(b): Initial and Annual Communications

Before Accepting the Initial Engagement: Rule 3526(a)

Before acceptance, the registered firm must describe in writing to the potential client’s audit committee all relationships between the firm or any of its affiliates and the prospective audit client or people in financial reporting oversight roles that may reasonably be thought to bear on independence. It must discuss the potential effects of those relationships if appointed and document the substance of the discussion.

An initial independence review should therefore occur early in an auditor selection or IPO-readiness process, rather than after the engagement letter is executed. It should cover the exact contracting firm, relevant affiliates, service history, and covered relationships.

At Least Annually: Rule 3526(b)

For ongoing engagements, the firm must at least annually give the audit committee a written description of relevant relationships, discuss their potential effects on independence, affirm in writing that it is independent in compliance with Rule 3520 as of the communication date, and document the substance of the discussion. The rule does not specify a single universal calendar date for the annual communication.

The annual affirmation addresses independence as of the date of the communication. Independence must nevertheless be maintained throughout the applicable audit and professional engagement period; it is not a once-a-year check.

What Relationships Must Be Disclosed?

Rule 3526 focuses on relationships that may reasonably be thought to bear on independence, involving the registered firm or its affiliates and the audit client or relevant financial reporting oversight personnel. The assessment is broader than an inventory of engagements that management labels “consulting.”

Non-Audit Services and Fee Arrangements

Examples for review include tax services, valuation engagements, financial system implementation, internal audit assistance, accounting advisory engagements, contingent fee arrangements, and services performed by network or affiliated entities. Whether a particular service is permissible depends on the actual facts and applicable SEC/PCAOB rules.

Financial, Employment, and Business Relationships

Other relevant areas can involve financial interests, lending or business arrangements, employment relationships, family relationships, and individuals in financial reporting oversight roles (FROR). The review should consider acquisitions, subsidiaries, and changes in executive roles where relevant.

What Does a Financial Reporting Oversight Role Mean?

Under PCAOB Rule 3501, a financial reporting oversight role generally involves a position in which a person can or does exercise influence over the contents of the financial statements or those who prepare them. Finance executives and other senior reporting personnel may fall within the definition depending on their actual responsibilities. It is not simply a job-title checklist.

For prohibited services and restrictions, see SEC Auditor Independence Rules: Prohibited Non-Audit Services.

PCAOB Rule 3526 Independence Communication: Practical Workflow

Step 1: Define the Audit Client, Affiliates, and Relevant Period

Identify the issuer, subsidiaries and other entities included under the applicable independence framework, the legal audit firm, its relevant affiliates, and the audit and professional engagement periods. Corporate restructuring and IPO transactions can change the analysis.

Step 2: Gather Relationships and Services

Request internal independence confirmations, review service engagements and fees, screen relevant investment and business relationships, and identify financial reporting oversight personnel. Do not limit the search to arrangements maintained by the engagement partner.

Step 3: Assess Whether Each Relationship May Affect Independence

Evaluate the actual terms of each relationship against SEC and PCAOB criteria. Identify prohibited arrangements separately from permitted relationships that nevertheless warrant disclosure and discussion.

Step 4: Deliver Written Disclosure to the Audit Committee

Provide a tailored, dated disclosure describing relevant relationships and sufficient context for the audit committee to understand potential effects. The communication should be supplied in time for an informed discussion.

Step 5: Hold and Document a Substantive Discussion

Discuss the nature, timing, safeguards where relevant, and possible effects of identified relationships. Maintain documentation of participants, substantive questions, conclusions, and follow-up actions. Merely sending a PDF does not satisfy the separate discussion requirement.

Step 6: Complete the Annual Affirmation and Follow-Up

For recurring audits, address the written Rule 3520 affirmation required by 3526(b), taking account of the special 2019 staff guidance where a violation has been identified. Track changes throughout the year rather than waiting for the next communication cycle.

What If an Independence Violation Is Identified?

The PCAOB’s May 31, 2019 staff guidance addresses a specific circumstance under Rule 3526(b): the auditor identifies one or more independence violations, analyzes whether objectivity and impartiality were impaired, and the firm and audit committee determine that the engagement can continue under the applicable requirements. The guidance addresses how the annual affirmation should be worded in those circumstances.

Modified Affirmation Under the 2019 Staff Guidance

In the scenario addressed by the guidance, the firm should not make an unqualified statement that it is independent while simultaneously identifying violations. Instead, it should describe the violations and indicate that it would be independent except for the identified violation or violations, with an appropriate discussion and documentation of the assessment.

This is not a blanket permission to continue after a violation, a waiver of SEC independence rules, or a substitute for determining whether independence has actually been impaired. Relevant circumstances may require separate technical evaluation, consultation with counsel or SEC staff, consideration of audit-report implications, and decisions about continuing the engagement.

A Practical Example: Previously Unidentified Affiliate Service

Assume an audit firm discovers that an affiliate performed services for an issuer during a relevant period. The firm should determine the scope and timing of the work, assess whether an independence requirement was violated, evaluate the effect on objectivity and impartiality, discuss relevant facts with the audit committee, and document the resulting decisions. Whether an engagement can proceed cannot be concluded from the service name alone.

Rule 3526 vs. Rule 3520, Rule 3524, Rule 3525 and AS 1301

The requirements complement one another. Audit committee preapproval is important where required, but it cannot transform a prohibited service into a permissible service. Likewise, an AS 1301 audit discussion does not replace the specific independence communication required by Rule 3526.

Did PCAOB Rule 3526 Replace ISB Standard No. 1?

Yes. Rule 3526 superseded Independence Standards Board Standard No. 1 and related interpretations in 2008. An SEC technical amendment updated Item 407 of Regulation S-K to refer to the applicable PCAOB independence-communication requirements rather than the older ISB No. 1 reference.

This historical distinction matters when audit committee charters or older compliance templates still refer to an “ISB No. 1 letter.” Update those references and procedures to the current applicable PCAOB framework.

PCAOB Rule 3526 Audit Committee Checklist

• Confirm whether the communication is for an initial or continuing engagement.

• Identify the exact registered audit firm and relevant affiliates.

• Inventory non-audit services, fees and related financial or business relationships.

• Identify relevant financial reporting oversight personnel and changes in roles.

• Obtain written disclosure of relationships reasonably thought to bear on independence.

• Discuss the potential independence effects of those relationships with the auditor.

• For annual reviews, obtain the written Rule 3520 affirmation or appropriately addressed 2019 guidance scenario.

• Document the substance of the independence discussion, attendees and follow-up items.

• Confirm required audit committee preapproval for permissible audit and non-audit services.

• Escalate any suspected violation for a fact-specific independence assessment.

• Reassess independence after acquisitions, reorganizations, executive changes and new services.

• Retain the relevant correspondence and committee materials under the applicable records framework.

Sample Annual Independence Communication: Outline for Audit Committees

The following is an illustrative structure, not a substitute for a registered firm’s approved form or legal review. A firm must tailor the actual communication to its circumstances and applicable requirements.

Audit Committee Questions to Ask About Independence

• Which firm affiliates and network entities did you include in your review?

• Which non-audit services were performed during relevant periods, and by whom?

• Did any executive hiring, promotion, or other FROR change affect the analysis?

• How were proposed services assessed against SEC and PCAOB restrictions?

• What new relationships have arisen since the prior written communication?

• Were any exceptions, policy breaches, or independence violations identified?

• If a violation occurred, how was the effect on objectivity and impartiality evaluated?

• How will emerging issues be brought to the committee between annual reviews?

Common Mistakes in Rule 3526 Compliance

Treating the Written Letter as the Entire Requirement

Written disclosure does not replace the required discussion, and meeting minutes alone do not replace the written relationship inventory or annual affirmation. The rule requires several distinct actions.

Ignoring Affiliate Services or Historical Relationships

Overseas affiliates, legacy advisory assignments and changes in the audit client group can create relevant issues, especially with IPOs, SPACs or acquisitions. A one-office services log is an incomplete foundation for many issuers.

Assuming Preapproval Repairs an Independence Violation

An audit committee cannot make a prohibited service permissible through approval. The underlying independence criteria must be satisfied independently of procedural preapproval.

Using an Unqualified Affirmation Despite Identified Violations

The 2019 guidance addresses cases where a violation has been identified and the engagement can nevertheless continue under the relevant assessment. Language should reflect the identified facts; it is not appropriate simply to use the standard form without considering the guidance.

How Rule 3526 Matters When Hiring or Changing an SEC Auditor

At an auditor appointment, Rule 3526(a) makes independence evaluation part of the selection decision. Companies comparing PCAOB-registered firms should ask prospective engagement teams to identify relevant prior services and relationships before the engagement is accepted.

For ongoing relationships, Rule 3526(b) forms part of annual audit committee oversight. A material acquisition, a change in the finance leadership team, or new service requests may require timely re-evaluation, even though the formal communication is annual at a minimum.

For a broader selection framework, consult MBP Global’s PCAOB Registered Audit Firms: How to Find and Evaluate the Right Auditor.

For related public company compliance topics, see SEC Audit Requirements for Public Companies.

How MBP Global LLP Supports Independent Public Company Audits

For public companies and IPO candidates, Rule 3526 is one component of a larger independent auditor evaluation. The right engagement team should have relevant issuer audit expertise, robust independence procedures, an understandable communication plan and the resources to meet applicable reporting needs.

MBP Global LLP offers audit and assurance services for businesses with U.S. reporting and capital-markets requirements. Companies evaluating an engagement should confirm the firm’s current PCAOB registration, its independence for their specific circumstances, team experience and the scope of any proposed services.

Explore MBP Global Audit & Assurance Services or contact the firm to discuss a potential independent audit engagement. Engagement-specific independence assessments and required communications remain subject to applicable professional rules.

Frequently Asked Questions About PCAOB Rule 3526

What is PCAOB Rule 3526?

It requires registered public accounting firms to make specified written disclosures and discussions about independence with audit committees before accepting initial PCAOB engagements and at least annually for ongoing audit clients.

What is the difference between Rule 3526(a) and 3526(b)?

Subsection (a) governs initial engagement communications before acceptance. Subsection (b) governs at-least-annual communications and adds a written affirmation of independence under Rule 3520.

Does Rule 3526 require an annual independence letter?

It requires an at-least-annual written disclosure of relevant relationships and a written affirmation of independence, alongside discussion and documentation. The rule does not prescribe one universal annual date.

What relationships must the auditor disclose?

Relationships between the firm or its affiliates and the audit client or persons in financial reporting oversight roles that may reasonably be thought to bear on independence.

What is a financial reporting oversight role?

A role involving influence over financial statement contents or those preparing them, as defined under PCAOB Rule 3501 and applied to the specific facts.

Can the audit committee approve a prohibited non-audit service?

No. Required preapproval cannot override substantive SEC or PCAOB independence prohibitions.

What happens if an independence violation is discovered?

The firm must assess the specific facts and effects on independence, communicate appropriately with the audit committee, and consider all applicable regulatory and reporting consequences. The 2019 staff guidance discusses a modified annual affirmation in a specific scenario.

Did Rule 3526 supersede ISB No. 1?

Yes. It superseded ISB No. 1 and related interpretations in 2008; SEC disclosure references were updated accordingly.

Is Rule 3526 the same as AS 1301?

No. AS 1301 covers audit committee communications about audit matters; Rule 3526 specifically concerns independence communications. Both may apply.

Can a firm use the same template every year?

A consistent format can help, but disclosure and affirmation content must reflect current relationships, facts and any identified violations. A generic template alone is insufficient.

Conclusion: Make Independence Communications Part of Active Oversight

PCAOB Rule 3526 is designed to bring meaningful transparency to auditor independence. Its initial and annual written disclosures, committee discussions, and documentation requirements help public company decision-makers evaluate risks that could affect an audit engagement. A practical compliance process combines substantive independence screening, timely committee involvement, accurate affirmation language, and a record of the discussion.

For companies considering a new independent auditor, early evaluation of historical services and financial reporting oversight relationships can reduce avoidable disruption. Review relevant SEC and PCAOB requirements with qualified professionals before relying on an auditor appointment or public filing.