The Internal Revenue Service (IRS) assigns an employer identification number to every business or non-personal entity (like a club) that requests one. The EIN is to an organization what a Social Security Number is to a person--an official tax identifier used for filing returns and opening banking accounts.

EIN Structure

EINs are nine-digit numbers. Unlike Social Security Numbers, which are in the format 123-45-6789, EINs are in the format 12-3456789. The first two digits had a positional logic, and the remaining six were simply the next numbers in the sequence with no intrinsic meaning.

Prefix Code History

Before 2001, the first two characters of the EIN (called a "prefix code") represented the general geographic area in which a business was expected to operate. After 2001, the code no longer applied in the same way; instead of referring to the business's geographic area, it reflected the location of the IRS office that processed the EIN request.

Prefix Codes

Prefix codes, by assigning city, are as follow: Andover (10, 12), Atlanta (60, 67), Austin (50, 53), Brookhaven (01, 02, 03, 04, 05, 06, 11, 13, 14, 16, 21, 22, 23, 25, 34, 51, 52, 54, 55, 56, 57, 58, 59, 65), Cincinnati (30, 32, 35, 36, 37, 38, 61), Fresno (15, 24), Kansas City (40, 44), Memphis (94, 95), Ogden (80, 90), Philadelphia (33, 39, 41, 42, 43, 45, 46, 47, 48, 62, 63, 64, 66, 68, 71, 72, 73, 74, 75, 76, 77, 81, 82, 83, 84, 85, 86, 87, 88, 91, 92, 93, 98, 99), Internet (20, 26, 27), Small Business Administration (31).

Remaining Digits

The final six digits of an EIN have no significance whatsoever--they are assigned in sequence with no special positional logic. However, two new EINs may not be issued with consecutive numbers.

Recycling EINs

When a company or organization dissolves, the EIN is deactivated. It is possible that an EIN may be re-used at a future date, although the statistical incidence of this happening is fairly small.