Generally, the IRS can include returns filed within the last three years in an audit. If we identify a substantial error, we may add additional years. We usually don’t go back more than the last six years.
The IRS tries to audit tax returns as soon as possible after they are filed. Accordingly most audits will be of returns filed within the last two years.
If an audit is not resolved, we may request extending the statute of limitations for assessment tax. The statute of limitations limits the time allowed to assess additional tax. It is generally three years after a return is due or was filed, whichever is later. There is also a statute of limitations for making refunds. Extending the statute gives you more time to provide further documentation to support your position; request an appeal if you do not agree with the audit results; or to claim a tax refund or credit. It also gives the IRS time to complete the audit and provides time to process the audit results.
You don’t have to agree to extend the statute of limitations date. However if you don’t agree, the auditor will be forced to make a determination based upon the information provided.
You can find more information about extending a statute of limitations in Publication 1035, Extending the Tax Assessment Period PDF, or from your auditor.