AICPA, Tax Insider
During the course of an IRS investigation, the IRS has the authority to issue an administrative summons seeking records and testimony (Sec. 7602). The IRS may summons records, whether they are in the taxpayer’s or a third party’s possession, including in the possession of the taxpayer’s business associates, acquaintances, prior employers, and even financial institutions (Internal Revenue Manual (IRM) §18.104.22.168). One exception to this sweeping rule is that the IRS may not issue a summons or commence an enforcement proceeding if the IRS has referred a criminal tax case to the Department of Justice (Sec. 7602(d)).