Best Practices for TIN Verifications

The following are requirments and best practices when performing a TIN Verification with Abound. This applies to the /tin-verification endpoint along with TIN Verifications triggered during W-9, W-8BEN, W-8BEN-E or 1099 activities.

Requirements for the name Field

Due to IRS limitations, Abound only accepts certain ASCII characters in the name field when performing a TIN Verification. These characters include:

  • Letters: A-Z
  • Letters: a-z
  • Numbers: 0-9
  • Ampersands: &
  • Hyphens: -
  • Spaces: 

If you include any other characters in the name field, you will receive a 400 Bad Request error.

Requirements for the tin Field

The tin field must contain exactly nine digits and only include numbers 0 through 9. If you include any other characters in the tin field, you will receive a 400 Bad Request error.

Pre-Processing Steps

Before submitting a TIN Verification request to the IRS, Abound will perform certain steps to ensure the name field is formatted correctly. These steps include:

  • Replacing accent characters with their ASCII equivalent (e.g. “é” becomes “e”)
  • Removing leading and trailing whitespace characters
  • If necessary, truncating the name field to 70 characters (an IRS requirement)

These pre-processing actions are not reflected in the TIN Verification name response and are subject to change.

Best Practices

  1. Verify Payload Accuracy: Ensure that Employer Identification Numbers (EINs) are associated with the correct business entity name. Include entity designations (e.g., “Inc.”, “LLC”) only if they are part of the legal business name. For Social Security Numbers (SSNs) and Individual Taxpayer Identification Numbers (ITINs), pair the identifier with the individual’s legal first and last name.
  2. Omit Middle Names or Initials: Although including a middle name or initial might seem to enhance specificity, it does not improve IRS lookup accuracy. Please exclude middle names or initials from the name field.
  3. Avoid Non-English Character Sets: The IRS supports only a limited set of ASCII characters in the name field. Non-English character sets should not be used.
  4. Do Not Including Honorifics: When submitting information for an INDIVIDUAL, please remove all leading and trailing honorifics (e.g. “Ms.”, “Dr.”, “Jr.”, “IV”).

Recently registered TINs

Newly registered TINs can sometimes be delayed in finding their way into the IRS’s system. In the case of such delay, you will receive a MISMATCH until the IRS system is updated. If you think this case applies to you, please reach out to us and we’d be happy to assist in a solution.

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