NumberResearch Membership · Data 09/20/2026

Recent prefix assignments

0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/20/2026

Full prefixes (NXX) Thousands-blocks (1,000-number pools)

The Code holder is who opened each NPA-NXX prefix — not necessarily who holds the numbers. A prefix is 10,000 numbers, but under pooling its ten 1,000-number blocks are handed out individually, often to different carriers; the code holder may hold only one block, or none. The Thousands-blocks column shows how the ten blocks are really split — click which blocks → to see who holds each 1,000-number block and its last-4-digit range. Assignments are initial assignments; the current serving carrier may differ due to portability.

Most active assignees, all time — NPA 661
PACIFIC BELL 145
PACIFIC BELL (COMPETITIVE) 1
New assignments by month Sep 2026 Aug 2026 Jul 2026 Jun 2026 May 2026 Apr 2026 Mar 2026 Feb 2026 Jan 2026 Dec 2025 Nov 2025 Oct 2025
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Recent NPA-NXX prefix assignments
AssignedNPA-NXXThousands-blocks taken (last-4 opening)Code holderOCNRate centerState
— 661-299 7XXX8XXX · 2 holders which blocks → PACIFIC BELL 9740 SNCA SGCC CA
— 661-321 6XXX which blocks → PACIFIC BELL 9740 BKFD MAIN CA
— 661-322 not yet reported which blocks → PACIFIC BELL 9740 BKFD MAIN CA
— 661-323 not yet reported which blocks → PACIFIC BELL 9740 BKFD MAIN CA
— 661-324 not yet reported which blocks → PACIFIC BELL 9740 BKFD MAIN CA
— 661-325 not yet reported which blocks → PACIFIC BELL 9740 BKFD MAIN CA
— 661-326 not yet reported which blocks → PACIFIC BELL 9740 BKFD MAIN CA
— 661-327 not yet reported which blocks → PACIFIC BELL 9740 BKFD MAIN CA
— 661-328 not yet reported which blocks → PACIFIC BELL 9740 BKFD MAIN CA
— 661-334 0XXX which blocks → PACIFIC BELL 9740 BKFD MAIN CA
— 661-335 1XXX2XXX which blocks → PACIFIC BELL 9740 BKFD MAIN CA
— 661-336 1XXX2XXX4XXX8XXX9XXX · 4 holders which blocks → PACIFIC BELL 9740 BKFD MAIN CA
— 661-337 0XXX1XXX2XXX4XXX5XXX8XXX9XXX · 2 holders which blocks → PACIFIC BELL 9740 BKFD MAIN CA
— 661-363 3XXX9XXX · 2 holders which blocks → PACIFIC BELL 9740 BKFD MAIN CA
— 661-364 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX which blocks → PACIFIC BELL 9740 BKFD MAIN CA
— 661-366 not yet reported which blocks → PACIFIC BELL 9740 BKFD MAIN CA
— 661-387 2XXX3XXX4XXX5XXX8XXX · 4 holders which blocks → PACIFIC BELL 9740 BKFD NORTH CA
— 661-391 not yet reported which blocks → PACIFIC BELL 9740 BKFD NORTH CA
— 661-392 not yet reported which blocks → PACIFIC BELL 9740 BKFD NORTH CA
— 661-393 not yet reported which blocks → PACIFIC BELL 9740 BKFD NORTH CA
— 661-394 0XXX2XXX9XXX · 3 holders which blocks → PACIFIC BELL 9740 BKFD MAIN CA
— 661-395 not yet reported which blocks → PACIFIC BELL 9740 BKFD MAIN CA
— 661-396 5XXX which blocks → PACIFIC BELL 9740 BKFD SOUTH CA
— 661-397 not yet reported which blocks → PACIFIC BELL 9740 BKFD SOUTH CA
— 661-398 not yet reported which blocks → PACIFIC BELL 9740 BKFD SOUTH CA
— 661-399 not yet reported which blocks → PACIFIC BELL 9740 BKFD NORTH CA
— 661-424 2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → PACIFIC BELL 9740 SNCA SGCC CA
— 661-513 3XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → PACIFIC BELL 9740 SNCA SGCC CA
— 661-533 4XXX which blocks → PACIFIC BELL 9740 PLDL PLDL CA
— 661-537 3XXX4XXX5XXX · 2 holders which blocks → PACIFIC BELL 9740 PLDL PLDL CA
— 661-538 not yet reported which blocks → PACIFIC BELL 9740 PLDL PLDL CA
— 661-540 3XXX which blocks → PACIFIC BELL 9740 PLDL PLDL CA
— 661-572 not yet reported which blocks → PACIFIC BELL 9740 PLDL PLDL CA
— 661-574 5XXX which blocks → PACIFIC BELL 9740 PLDL PLDL CA
— 661-575 3XXX4XXX5XXX6XXX7XXX · 3 holders which blocks → PACIFIC BELL 9740 PLDL PLDL CA
— 661-587 not yet reported which blocks → PACIFIC BELL 9740 BKFD NORTH CA
— 661-588 not yet reported which blocks → PACIFIC BELL 9740 BKFD NORTH CA
— 661-589 not yet reported which blocks → PACIFIC BELL 9740 BKFD NORTH CA
— 661-607 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → PACIFIC BELL 9740 SNCA NHCS CA
— 661-631 not yet reported which blocks → PACIFIC BELL 9740 BKFD MAIN CA
— 661-632 6XXX which blocks → PACIFIC BELL 9740 BKFD MAIN CA
— 661-633 4XXX which blocks → PACIFIC BELL 9740 BKFD MAIN CA
— 661-634 5XXX8XXX · 2 holders which blocks → PACIFIC BELL 9740 BKFD MAIN CA
— 661-635 not yet reported which blocks → PACIFIC BELL 9740 BKFD MAIN CA
— 661-636 1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → PACIFIC BELL 9740 BKFD MAIN CA
— 661-637 3XXX5XXX6XXX9XXX · 3 holders which blocks → PACIFIC BELL 9740 BKFD MAIN CA
— 661-638 3XXX6XXX8XXX9XXX · 3 holders which blocks → PACIFIC BELL 9740 BKFD MAIN CA
— 661-654 1XXX9XXX · 2 holders which blocks → PACIFIC BELL 9740 BKFD SOUTH CA
— 661-663 not yet reported which blocks → PACIFIC BELL 9740 BKFD SOUTH CA
— 661-664 not yet reported which blocks → PACIFIC BELL 9740 BKFD SOUTH CA

Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/20/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.