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 650
PACIFIC BELL 273
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
— 650-524 5XXX which blocks → PACIFIC BELL 9740 SAN MATEO CA
— 650-525 2XXX4XXX6XXX · 2 holders which blocks → PACIFIC BELL 9740 SAN MATEO CA
— 650-526 1XXX2XXX4XXX8XXX · 4 holders which blocks → PACIFIC BELL 9740 MT VIEW CA
— 650-527 not yet reported which blocks → PACIFIC BELL 9740 MT VIEW CA
— 650-528 2XXX which blocks → PACIFIC BELL 9740 MT VIEW CA
— 650-529 4XXX5XXX6XXX7XXX · 4 holders which blocks → PACIFIC BELL 9740 WOODSIDE CA
— 650-542 0XXX1XXX2XXX3XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → PACIFIC BELL 9740 REDWOOD CY CA
— 650-548 not yet reported which blocks → PACIFIC BELL 9740 SAN MATEO CA
— 650-550 0XXX1XXX2XXX3XXX4XXX5XXX8XXX9XXX · 5 holders which blocks → PACIFIC BELL 9740 SNFC JUNPR CA
— 650-551 9XXX which blocks → PACIFIC BELL 9740 SNCRL-BLMT CA
— 650-552 3XXX4XXX6XXX7XXX8XXX · 5 holders which blocks → PACIFIC BELL 9740 MILLBRAE CA
— 650-553 not yet reported which blocks → PACIFIC BELL 9740 SSNFRNCSCO CA
— 650-554 0XXX1XXX8XXX9XXX which blocks → PACIFIC BELL 9740 SAN MATEO CA
— 650-556 3XXX4XXX5XXX6XXX which blocks → PACIFIC BELL 9740 REDWOOD CY CA
— 650-557 2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → PACIFIC BELL 9740 PACIFICA CA
— 650-558 not yet reported which blocks → PACIFIC BELL 9740 SAN MATEO CA
— 650-559 4XXX6XXX which blocks → PACIFIC BELL 9740 LOS ALTOS CA
— 650-560 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → PACIFIC BELL 9740 HALFMOONBY CA
— 650-561 2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → PACIFIC BELL 9740 PALO ALTO CA
— 650-562 5XXX6XXX7XXX8XXX · 3 holders which blocks → PACIFIC BELL 9740 REDWOOD CY CA
— 650-563 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → PACIFIC BELL 9740 MOSS BEACH CA
— 650-564 2XXX3XXX4XXX5XXX7XXX · 3 holders which blocks → PACIFIC BELL 9740 MT VIEW CA
— 650-565 not yet reported which blocks → PACIFIC BELL 9740 PALO ALTO CA
— 650-566 not yet reported which blocks → PACIFIC BELL 9740 PALO ALTO CA
— 650-567 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → PACIFIC BELL 9740 MT VIEW CA
— 650-568 not yet reported which blocks → PACIFIC BELL 9740 REDWOOD CY CA
— 650-569 0XXX1XXX which blocks → PACIFIC BELL 9740 REDWOOD CY CA
— 650-570 none assigned yet which blocks → PACIFIC BELL 9740 SAN MATEO CA
— 650-571 none assigned yet which blocks → PACIFIC BELL 9740 SAN MATEO CA
— 650-572 not yet reported which blocks → PACIFIC BELL 9740 SAN MATEO CA
— 650-573 not yet reported which blocks → PACIFIC BELL 9740 SAN MATEO CA
— 650-574 9XXX which blocks → PACIFIC BELL 9740 SAN MATEO CA
— 650-577 3XXX which blocks → PACIFIC BELL 9740 SAN MATEO CA
— 650-578 not yet reported which blocks → PACIFIC BELL 9740 SAN MATEO CA
— 650-579 not yet reported which blocks → PACIFIC BELL 9740 SAN MATEO CA
— 650-583 not yet reported which blocks → PACIFIC BELL 9740 SSNFRNCSCO CA
— 650-584 0XXX3XXX · 2 holders which blocks → PACIFIC BELL 9740 MT VIEW CA
— 650-588 not yet reported which blocks → PACIFIC BELL 9740 SSNFRNCSCO CA
— 650-589 not yet reported which blocks → PACIFIC BELL 9740 SSNFRNCSCO CA
— 650-591 not yet reported which blocks → PACIFIC BELL 9740 SNCRL-BLMT CA
— 650-592 not yet reported which blocks → PACIFIC BELL 9740 SNCRL-BLMT CA
— 650-593 not yet reported which blocks → PACIFIC BELL 9740 SNCRL-BLMT CA
— 650-594 6XXX7XXX · 2 holders which blocks → PACIFIC BELL 9740 SNCRL-BLMT CA
— 650-595 6XXX which blocks → PACIFIC BELL 9740 SNCRL-BLMT CA
— 650-596 not yet reported which blocks → PACIFIC BELL 9740 SNCRL-BLMT CA
— 650-598 not yet reported which blocks → PACIFIC BELL 9740 SNCRL-BLMT CA
— 650-599 not yet reported which blocks → PACIFIC BELL 9740 REDWOOD CY CA
— 650-603 0XXX1XXX5XXX6XXX · 4 holders which blocks → PACIFIC BELL 9740 MT VIEW CA
— 650-604 not yet reported which blocks → PACIFIC BELL 9740 MT VIEW CA
— 650-607 not yet reported which blocks → PACIFIC BELL 9740 SNCRL-BLMT 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.