What is a Taxpayer Identification Number (TIN)?

A TIN is defined as the identifying number assigned to a person or entity under Internal Revenue Code, Section 6109. A TIN may be a SSN, EIN, ITIN or ATIN. A TIN can have only nine (9) numbers. It cannot have more or less than nine numbers nor can it have letters.

  • An SSN is a Social Security Number issued by the Social Security     Administration.
  • An EIN is an Employer Identification Number (EIN) issued by the IRS.
  • An ITIN is an Individual Taxpayer Identification Number issued by the IRS. Resident aliens and nonresident aliens, who are not eligible for SSNs, use ITINS. An ITIN is an individual Taxpayer Identification Number (ITIN) issued by the IRS and may be used as a TIN to meet federal tax obligations only. An ITIN has nine numbers in the same format as an SSN and always begins with the number 9. The fourth and fifth digits are always within the range of 70 through 88.
  • An ATIN is an Adoptive Taxpayer Identification Number issued by the IRS. An ATIN is only a temporary taxpayer identification number issued for a child born, and adopted, in the United States. An ATIN should be requested when an SSN cannot be obtained in time to file your tax return. Once the adoptive parent obtains an SSN for the adoptive child, the ATIN becomes obsolete. An ATIN contains nine numbers in the same format as an SSN.

For additional information see Publication 1281, Online TIN Matching Program.

What files do the IRS use in the matching process?

  • The DM-1 File — A file containing all SSNs ever issued by the SSA
  • The EIN-Name Control File — A file containing all the IRS-assigned EINs
  • The ITIN File — A file containing all the IRS-assigned ITINs (On DM-1)
  • The ATIN File — A file containing all the IRS-assigned ATINs (On DM-1)

How is a Name/TIN mismatch identified?

A Name/TIN combination is incorrect if it does not match, or cannot be found, on IRS or SSA files. For example, a Name/TIN mismatch occurs when an individual name is submitted with a TIN not associated with the individual name provided. A TIN is not interchangeable with different names. A business EIN must be used for a partnership, corporation, or non-disregarded Limited Liability Company (LLC). An SSN must be used with an individual name (In first name line). A Sole Proprietor must always provide his/her individual name. A Sole Proprietor may provide his/her Doing Business As (DBA) name (in second name line) in addition to the required individual name together with the matching SSN.

For additional information see Publication 1281, Backup Withholding.

Who will be able to use the TIN Matching Program and how will it help me to reduce errors on my payee TINs?

Payers or their authorized agents, who submit Forms 1099-INT, DIV, PATR, OID, MISC and/or B* to IRS may be eligible to enroll in the e-Services TIN Matching program. TIN Matching assists the payer in determining if the payee TIN/name combination contained on their Form W-9, matches the TIN/name combination contained in IRS tax filing records. NOTE: The TIN Matching program currently cannot enroll payers who do not submit at least one of these six forms, nor employers submitting Forms W-2, to use the TIN Matching system. Payers may only perform TIN Matching for the TIN/Name combinations for income subject to backup withholding and reported on Forms 1099-B, DIV, INT, MISC, OID and/or PATR.

For additional information see Publication 2108a, Online TIN Matching Program.