Original Assignee

NANP · also called initial assignee, assignee of record

The service provider a prefix or block was first assigned to — not necessarily the carrier serving a number today.

The original (or initial) assignee is the service provider to whom a central-office code or thousands-block was first allocated in the numbering administrator's records. Public assignment data identifies this initial assignee.

Because of number portability, the original assignee is frequently not the carrier that serves a given number today: subscribers can port their number to another provider while keeping it. This distinction is one of the most common errors in reading numbering data.

Carrier names are illustrative. The lesson is real: the assignment record (who a prefix was handed to) is not the current carrier (who serves a number now). After a port they differ — which is why an area code, or an old assignment table, cannot tell you who a number belongs to today.

Common misconception.

Assignment records are not a current-carrier lookup. The company listed against a prefix is who it was assigned to, which — after portability — may differ from who serves any individual number now.