Circular 230 Due Diligence and What It Demands of Your Tax Practice

Every return you sign carries your name and your license. Circular 230 is the rulebook that decides whether you handled that return the way the government expects, and due diligence is the part of it that trips up the most practitioners. Most violations are not fraud. They are good preparers who got busy, took a client at their word, and skipped a question they should have asked.

This guide breaks down what the rule actually requires, when you can rely on what a client tells you, what changes when someone else does the work, and what the IRS can do if you fall short. If you run a busy tax practice, the review habits below are the ones worth building before next filing season, not during it.

Circular 230 is the rulebook for practice before the IRS

It is the common name for Treasury Department Circular 230, published at 31 CFR Part 10 in the Code of Federal Regulations. It holds the regulations governing practice before the Internal Revenue Service, and it binds tax return preparers, attorneys, CPAs, enrolled agents, and anyone else who represents taxpayers or prepares their returns. Every preparer who signs a return sits under it.

The Department of the Treasury writes the rules. The Office of Professional Responsibility, known as OPR, enforces them. That office sits inside the IRS and has the authority to investigate conduct, bring charges, and recommend discipline against a practitioner who breaks the standards. You can read the full text on the IRS Circular 230 and OPR page, and the complete regulation lives in the Circular 230 PDF. The piece almost everyone needs to understand sits in Section 10.22.

The due diligence standard, in plain terms

Section 10.22 is titled "Diligence as to accuracy," and the heart of it is short. A practitioner must exercise due diligence in three places.

First, in preparing or assisting in the preparation of, approving, and filing tax returns, documents, and other papers relating to IRS matters. You approve and file them, so the accuracy is yours. Second, in determining the correctness of oral or written representations made by the practitioner to the Department of the Treasury. Third, in determining the correctness of representations made by the practitioner to clients with reference to any matter administered by the IRS.

Read that last one twice. The diligence required under Circular 230 covers what you tell your client, not only what you file. If you give a client a confident answer about a federal tax position and you never checked it, you have a problem under the same rule that governs the return itself. Accuracy in returns or other documents and accuracy in your advice are held to one standard.

When you can rely on a client's word, and when you cannot

Here is the part preparers misread most. You do not have to audit your clients. Under the rules, a practitioner may rely in good faith without verification upon information furnished by the client. You can take the numbers a taxpayer hands you and use them.

The line sits in the next sentence. You may not ignore the implications of information already in front of you, and you must make reasonable inquiries if the information furnished appears to be incorrect, inconsistent with something else you know, or incomplete. Good faith without verification upon information furnished by the client is the rule. Willful blindness is not.

A simple example. A client reports a home office but also tells you the business runs entirely out of a rented warehouse. That contradiction is your cue. One reasonable inquiry clears it up, and asking it is the difference between diligence and a violation. When something on a client's tax return does not add up, the obligation to advise the client and to ask before you file belongs to you.

What changes when someone else does the work

Most firms today do not prepare every return alone. Work gets reviewed, delegated, and increasingly sent to an offshore team. The regulation anticipated this, and Section 10.22(b) is the rule that matters.

You are presumed to have exercised due diligence when a practitioner relies on the work product of another person, as long as you used reasonable care in engaging, supervising, training, and evaluating the person, taking proper account of the nature of the relationship between you and that person. In plain language, you can rely on someone else's work product. You stay responsible for how you chose, trained, and checked them.

That is the standard any outsourcing arrangement has to clear. Reasonable care in engaging a provider means vetting them properly before a single return moves, which is why our breakdown of outsourcing red flags exists. Supervise and evaluate means a real review layer sits between their work and your signature, the kind we build into audit and assurance and tax preparation workflows. The nature of the relationship is something you set up front, during onboarding, and document through clear data handling shown in our data security checklist. Done right, an offshore partner makes 10.22(b) easier to meet, because the engaging, training, and review you need are already structured.

Due diligence obligations beyond Circular 230

The rule is the baseline. Several specific areas carry their own due diligence requirements on top of it, and missing them is a fast route to penalties.

Refundable credits are the big one. Paid preparers filing tax returns that claim the Earned Income Tax Credit, the Child Tax Credit, the Additional Child Tax Credit, or the American Opportunity Credit face separate diligence required under the Internal Revenue Code, with Form 8867 and recordkeeping that go further than the general standard. Earned income claims in particular draw scrutiny, so the questions and the documentation both matter.

Foreign accounts carry their own duty too. Your due diligence obligations and the Report of Foreign Bank and Financial Accounts mean asking clients the right questions about offshore holdings, since taxpayers cannot hide foreign bank accounts to avoid reporting and you cannot look past signs that they exist. The IRS lays out the rules on its FBAR page. For CPAs there is also a parallel set of professional standards. The AICPA Statements on Standards for Tax Services run alongside Circular 230, and the standards for tax services often ask for the same care from a different direction.

What happens when a practitioner falls short

The OPR does not hand out parking tickets. A disciplinary case under the rule can lead to censure, suspension, or disbarment from practice before the IRS, and contested cases are heard by an administrative law judge. Losing the right to represent clients before the agency ends a tax practice in a way no client refund ever could.

The pressure has gone up, not down. The IRS issued public notice of a "sweeping effort to restore fairness" to the tax system, and that IRS news release signaled heavier enforcement attention on high-income returns and the preparers behind them. Filing season is when corners get cut, and it is also when a thin review process shows. For unenrolled preparers, staying in the Annual Filing Season Program keeps you inside the IRS system and on record as meeting its standards.

The fix is not complicated and it is not seasonal. Build the questions into your intake, keep a review step you actually follow, and write down the reasonable inquiries you made. If you want help setting up an offshore workflow that holds the Circular 230 line instead of straining it, our team is glad to walk through it.

Frequently asked questions

1. What is Circular 230 due diligence? It is the standard in Section 10.22 of Circular 230 that requires a tax practitioner to exercise due diligence as to accuracy when preparing returns, filing documents, and advising clients on any matter administered by the IRS. It covers both what you submit and what you tell clients.

2. What does "exercise due diligence" mean in practice? It means checking your work to a reasonable standard rather than guessing. You confirm the figures you can, ask about anything that looks off, and avoid signing returns or other documents you have reason to doubt. The test is reasonable care, not perfection.

3. Can a tax practitioner rely on information from a client without verifying it? Yes, within limits. A practitioner may rely in good faith without verification upon information furnished by the client. You must make reasonable inquiries, though, if the information appears to be incorrect, incomplete, or inconsistent with something you already know.

4. Does Circular 230 let me rely on an offshore team's work product? Yes. Section 10.22(b) lets you rely on the work product of another person when you use reasonable care in engaging, supervising, training, and evaluating them. You stay responsible for vetting the provider and reviewing the output before you sign.

5. What is the Office of Professional Responsibility? The Office of Professional Responsibility is the IRS body that enforces Circular 230. It investigates practitioner conduct and can pursue disciplinary action, including suspension or disbarment, in cases heard by an administrative law judge.

6. What are the penalties for a Circular 230 due diligence violation? Penalties range from a private reprimand to censure, suspension, or disbarment from representing clients before the IRS. The Internal Revenue Code also carries separate monetary penalties for preparers who miss credit due diligence requirements, such as those tied to the Earned Income Tax Credit.

7. How is credit due diligence different from Circular 230 due diligence? Circular 230 sets the general accuracy standard for your whole tax practice. Credit due diligence is narrower and stricter, applying to specific refundable credits like the Earned Income Tax Credit and the Additional Child Tax Credit, with required forms and records on every qualifying return.

8. Is Circular 230 the same as the AICPA Statements on Standards for Tax Services? No. Circular 230 is federal regulation enforced by the IRS. The Statements on Standards for Tax Services are professional standards from the AICPA. They overlap heavily on accuracy and reasonable inquiry, so a CPA has to satisfy both at once.

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