1. Understanding an IRS Examination
A correspondence examination is a common form of IRS audit and is generally handled by mail. The IRS may request verification of particular items reported on a return, including income, deductions, or tax credits. Taxpayers should review the notice alongside the filed return before deciding what information to provide.
Different IRS Notices Serve Different Purposes
A Letter 566 generally requests documents supporting items being examined. A CP2000 serves a different purpose. It is generated through the IRS Automated Underreporter program when information reported by third parties does not appear to match information on the taxpayer's return.
A Statutory Notice of Deficiency comes at a later procedural stage and formally determines a deficiency, providing a limited period in which the taxpayer may petition the U.S. Tax Court.
Understanding which type of notice has arrived matters because the appropriate response and available procedures can differ. Taxpayers facing an examination can seek assistance through an IRS tax audit defense attorney before submitting records or agreeing to a proposed adjustment.
2. Common Issues That Trigger Audit Disputes
Discrepancies between a tax return and information reported to the IRS by third parties are a frequent source of inquiries. Forms W-2, 1099, and 1099-K may reveal amounts that do not appear to match reported income. Business deductions can also draw scrutiny when the available records do not adequately establish the amount or business purpose of an expense.
Income and Business Expense Discrepancies
When reported income differs from third-party information, taxpayers should determine why the discrepancy occurred rather than assuming that every amount identified by the IRS represents additional taxable income. Bank transfers, loans, reimbursements, and other transactions may require documentation showing their actual character.
Business deductions present a different problem. Expenses generally must satisfy the applicable deduction requirements and be supported by adequate records. Common areas of dispute include vehicle expenses, travel and meals, home-office deductions, and other business costs for which documentation is incomplete.
Vehicle and certain travel-related expenses may be subject to heightened substantiation requirements under IRC §274(d), while home-office deductions generally depend on requirements under IRC §280A, including applicable exclusive and regular use standards.
Worker Classification and Payroll Issues
Audits can also expose disagreements over whether a worker was properly treated as an independent contractor rather than an employee. The tax consequences may extend beyond the original income-tax issue because worker classification can affect withholding and employment-tax obligations.
Businesses facing these issues should examine the actual working relationship rather than relying only on how the parties described the arrangement. Additional information about related federal obligations is available through Payroll Tax Compliance.
3. How to Respond to an IRS Audit Notice
An effective response begins with the notice itself. Taxpayers should determine exactly what the IRS is questioning and compare those items with the return and underlying records before sending documents.
Review and Organize Supporting Records
Relevant records may include receipts, canceled checks, invoices, bank statements, mileage records, contracts, and accounting records. When gross receipts are questioned, bank deposits should be reconciled with reported income so that transfers, loan proceeds, reimbursements, or other potentially non-income deposits can be identified and documented.
A summary schedule can also help connect supporting records with the particular return items under examination. The goal is not simply to produce a large volume of documents but to provide an organized response that addresses the questions raised by the IRS.
Keep the Response Focused
Under IRC §7602, the IRS has broad statutory authority to examine books, records, and other information relevant to determining tax liability. Taxpayers should therefore provide accurate and complete information required by a lawful request while keeping submissions organized and responsive to the matters being examined.
Unstructured or unrelated records can make it more difficult to establish what a particular document proves. A focused submission allows supporting evidence to be evaluated in connection with the disputed return item.
4. Challenging IRS Findings and Administrative Appeals
An examiner's proposed adjustment does not necessarily determine the final outcome of the dispute. Taxpayers may be able to challenge factual errors, provide additional evidence, dispute an income reconstruction, or explain why a deduction should not have been disallowed.
Responding to Proposed Adjustments
When the IRS proposes additional tax, taxpayers should compare the examiner's calculations with their returns and supporting records before agreeing. This review may uncover duplicated income, incorrectly characterized deposits, unsupported assumptions, or overlooked documentation.
If the IRS provides an opportunity for administrative review, the applicable response deadline should be determined from the specific letter received. A formal written protest may be required in some cases.
IRS Appeals and Tax Court Review
Depending on the procedural posture of the case, a taxpayer may seek review through the IRS Independent Office of Appeals. More information about this stage is available through the Administrative Appeal Process.
If the matter remains unresolved and the IRS issues a Notice of Deficiency, IRC §6213 generally provides 90 days from the date the notice is mailed to petition the U.S. Tax Court. The statutory period is generally 150 days when the notice is addressed to a person outside the United States.
Because these filing periods can determine whether prepayment Tax Court review remains available, taxpayers should rely on the deadline stated in the applicable notice and confirm the governing statutory period.
5. When Legal Representation Is Appropriate
Some correspondence matters involve straightforward requests for documents and may be resolved without extensive representation. Legal assistance becomes more significant when the examination involves substantial proposed deficiencies, multiple tax years, disputed business records, employment-tax questions, penalties, or potential allegations of intentional misconduct.
Attorney-client privilege can protect qualifying confidential communications made for the purpose of obtaining legal advice. This should not be confused with the federally authorized tax practitioner privilege under IRC §7525, which has important statutory limitations and does not apply to communications concerning criminal tax matters.
An IRS tax audit defense attorney can evaluate the legal basis for proposed adjustments, communicate with the IRS under proper authorization, organize responses, preserve objections, and represent a taxpayer during applicable administrative proceedings.
6. Frequently Asked Questions
What Happens If a Taxpayer Misses the Deadline to Respond to an IRS Audit Letter?
The consequences depend on the notice and the stage of the examination. Failure to respond to an initial document request may cause the examiner to proceed without the requested substantiation and potentially disallow questioned items. A taxpayer who does not respond to a CP2000 may face further proposed adjustments and subsequent deficiency procedures where applicable. If a Notice of Deficiency is ultimately issued, the statutory deadline for filing a U.S. Tax Court petition becomes particularly important. Taxpayers should therefore determine the consequences of the specific notice rather than assuming that every missed IRS deadline produces the same result.
Can an IRS Correspondence Audit Turn Into a Criminal Tax Investigation?
Potentially. A civil examination can raise more serious concerns if evidence suggests intentional tax evasion, fraudulent reporting, falsified records, or other potentially criminal conduct. IRC §7201, for example, addresses willful attempts to evade or defeat federal tax.
The existence of an error or disputed deduction alone does not establish criminal tax liability. When questions involving possible willfulness or fraud arise, obtaining legal advice before making further substantive statements or submissions can be particularly important.
19 Aug, 2026
