What Is a Customer File Number for Taxes?
Learn about the customer file number on tax documents. Understand its function, where it appears, and its practical use in tax preparation.
A customer file number is an identifier found on certain tax documents. It helps streamline the handling of documents between the taxpayer and the third-party issuer, such as an employer or financial institution. While it appears on official tax forms, its primary role is not for direct identification by the Internal Revenue Service (IRS) for tax filing purposes.
Understanding the Customer File Number
A customer file number, sometimes called a control number or unique identifier, is an internal tracking code assigned by organizations that issue tax forms. Its purpose is to uniquely identify a specific tax document or account within the issuer’s records. This number is not a taxpayer identification number (TIN) like a Social Security Number (SSN), Individual Taxpayer Identification Number (ITIN), or Employer Identification Number (EIN), which are used by the IRS to identify taxpayers. The format of a customer file number can vary significantly between different issuers, often comprising a combination of letters, numbers, or special characters.
Where Customer File Numbers Appear
Customer file numbers commonly appear on various tax forms. On Form W-2, Wage and Tax Statement, this identifier is typically found in Box D, often labeled as “Control Number”. On forms within the 1099 series, such as Form 1099-B, a customer file number may be present and labeled as “Account Number” or a similar term. Its inclusion on these forms is at the discretion of the issuer, meaning not all W-2s or 1099s will necessarily have one. If multiple accounts exist for a recipient, the account number is required on 1099 forms to distinguish them.
Significance for Taxpayers
The primary significance of a customer file number for taxpayers lies in its utility for tax preparation software. This number allows tax software programs to electronically import wage and tax data directly from employers or financial institutions, simplifying the tax filing process. By entering the customer file number, the software can match the taxpayer’s specific document with the issuer’s records, facilitating automated data entry and reducing the chance of manual errors.
If a customer file number is missing or incorrect, it typically does not prevent a taxpayer from successfully filing their return. The IRS does not require this number for filing, so returns are generally not rejected due to its absence. However, without a correct customer file number, the automatic data import feature in tax preparation software may not function, requiring the taxpayer to manually enter all information from their tax forms. In such cases, taxpayers can leave the field blank in the software.