Under, 26 USC § 7602 the IRS has a broad authority to issue summonses to taxpayers as well as third parties. A summons can compel a taxpayer or a third party to testify in court or to produce documents relevant to an IRS investigation. A summons can be issued as part of either a regular audit or a criminal investigation. However, less serious inquiries are frequently made by Information Document Request, Form 4564. The issuance of a summons typically means the IRS is investigating the tax matter with some seriousness or that the taxpayer has failed to comply with previous voluntary requests for information.
Without an order from a District Court, an IRS summons is not self-enforcing, meaning that taxpayers and third parties who receive a summons are not compelled to respond without a court order. However, the IRS will almost definitely seek a court order to enforce their summons if a taxpayer decides not to comply. A District Court is also more likely to issue an order enforcing the summons if the taxpayer had previously ignored the summons. Before issuing an order, the District Court will require the taxpayer to appear in order to respond to the summons.
In order to enforce the Summons, the IRS must go to the District Court and demonstrate a good faith purpose to the summons, showing that it was issued for a legitimate purpose, seeks information relevant to that purpose, seeks information that the IRS does not already have and complies with the administrative steps required by the United States Code. Unlike a warrant for an arrest or search, probable cause is not required for the issuance of a summons.
A taxpayer who believes the summons has been improperly issued can move to quash the summons, removing any need to comply. To quash the summons, the taxpayer must move within twenty days to quash the summons. A summons can be challenged on a variety of grounds, including a failure to follow IRS administrative procedures, substantive grounds, Constitutional protections or attorney client privilege. While the IRS reportedly wins the vast majority of cases where a taxpayer attempts to challenge the summons, every year some taxpayers are able to quash an IRS summons. Regardless of the circumstances, the issuance of an IRS summons almost invariably means that the taxpayer is facing a serious tax matter that requires the services of a qualified attorney.