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A credit union account can be levied just like a bank account. No extra steps are required. A notice of levy is simply sent to the credit union either via the US Mail or electronically, or by hand. The IRS will search for accounts showing interest income (or any other reportable activity like mortgage interest) first by using the taqxpayers returns. In the day of electronic filing where ID numbers are required it has become even simpler. If these types of accounts are not found then all banks within a range of the taxpayers domicile are polled electronically for a Social Security number match (or employer ID number match) and when one or more are found the notice of levy follows right behind this.