Social Security Administration ceases using numerical sequencing

The last day the Social Security Administration (SSA) assigned a Social Security Number (SSN) based on the numeric order within a state’s allocation of the first 5 digits was 6/24/11. All unassigned numbers within the numeric sequence have now been placed in a random pool. Effective 6/27/11, the assignment of a new SSN is much like a lottery; a random number is drawn from the unassigned pool of 420 million numbers available for assignment.

For example, the Series of 048-15-xxxx was assigned to CT and was used to issue new SSNs. Effective 6/27, all of the possible unassigned numbers within that Series have been assigned to the random pool. Therefore someone in any state or an immigrant coming into the country could be assigned an SSN in the 048-15 series this year or any year in the future. There are 755 Series groups that were in the process of being assigned as of June 2011. There are over 75,000 groups have had all possible numbers within the group previously assigned.

For years we have used software with the assigned SSN groups and corresponding state/date range to validate the state and year of issuance an SSN. The fact that the SSA will no longer provide the ability to validate newly issued numbers has upset quite a few businesses and employers. However, these validations will still be useful, although they will diminish in value over time. Most people entering the workforce were assigned an SSN well before June 27, 2011. The primary people entering the workforce with a new randomly assigned SSN will be immigrants.

The Social Security Administration will continue to provide opportunities for direct name based SSN verification. Internet based verification services include:
• The Social Security Number Verification Service (SSNVS) which is free to use for wage reporting purposes
• eVerify
• Consent-Based SSN Verification Service (SBSV)
There are stipulations. For example, the cost for SBSV is $5,000 to sign-up and $5.00 per verification.

For questions about the randomization process, email or visit


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