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 443
VERIZON MARYLAND, INC. 56
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
2011-11-09 443-634 0–9 XXXwhole prefix which blocks → VERIZON MARYLAND, INC. 9212 WATERLO236 MD
2009-08-13 443-395 0–9 XXXwhole prefix which blocks → VERIZON MARYLAND, INC. 9212 ABERDEEN MD
2009-08-13 443-861 0–9 XXXwhole prefix which blocks → VERIZON MARYLAND, INC. 9212 ABERDEEN MD
2008-12-16 443-518 0–9 XXXall 10 · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 COLUMBIA MD
2008-08-28 443-654 0–9 XXXwhole prefix which blocks → VERIZON MARYLAND, INC. 9212 WATERLO236 MD
2007-10-18 443-792 0–9 XXXall 10 · 7 holders which blocks → VERIZON MARYLAND, INC. 9212 BRYNPKLNCM MD
2006-03-09 443-455 0–9 XXXall 10 · 5 holders which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
2004-03-19 443-353 0–9 XXXall 10 · 6 holders which blocks → VERIZON MARYLAND, INC. 9212 COCKEYSVL MD
2001-05-18 443-849 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 TOWSON MD
2001-04-20 443-967 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → VERIZON MARYLAND, INC. 9212 NORTH EAST MD
2001-03-19 443-998 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 PARKVILLE MD
— 443-203 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → VERIZON MARYLAND, INC. 9212 WEST RIVER MD
— 443-213 0–9 XXXall 10 · 7 holders which blocks → VERIZON MARYLAND, INC. 9212 PIKESVILLE MD
— 443-220 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 443-249 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → VERIZON MARYLAND, INC. 9212 STEVENSVL MD
— 443-259 5XXX9XXX which blocks → VERIZON MARYLAND, INC. 9212 COLUMBIA MD
— 443-260 9XXX which blocks → VERIZON MARYLAND, INC. 9212 SALISBURY MD
— 443-262 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 7 holders which blocks → VERIZON MARYLAND, INC. 9212 CENTREVL MD
— 443-263 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 443-274 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 7 holders which blocks → VERIZON MARYLAND, INC. 9212 SEVERN MD
— 443-285 1XXX2XXX3XXX9XXX which blocks → VERIZON MARYLAND, INC. 9212 COLUMBIA MD
— 443-287 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 443-357 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX which blocks → VERIZON MARYLAND, INC. 9212 PIKESVILLE MD
— 443-367 1XXX4XXX6XXX8XXX9XXX · 5 holders which blocks → VERIZON MARYLAND, INC. 9212 COLUMBIA MD
— 443-394 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 PIKESVILLE MD
— 443-436 2XXX which blocks → VERIZON MARYLAND, INC. 9212 WOODLAWN MD
— 443-444 0–9 XXXwhole prefix which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 443-445 0XXX1XXX2XXX3XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → VERIZON MARYLAND, INC. 9212 ELKRIDGE MD
— 443-476 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 ANNAPOLIS MD
— 443-479 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 WATERLO236 MD
— 443-482 5XXX6XXX which blocks → VERIZON MARYLAND, INC. 9212 ANNAPOLIS MD
— 443-512 1XXX2XXX3XXX4XXX5XXX6XXX7XXX9XXX · 4 holders which blocks → VERIZON MARYLAND, INC. 9212 EDGEWOOD MD
— 443-523 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 SALISBURY MD
— 443-535 1XXX2XXX3XXX4XXX5XXX6XXX7XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 COLUMBIA MD
— 443-543 4XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → VERIZON MARYLAND, INC. 9212 ARBUTUS MD
— 443-546 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → VERIZON MARYLAND, INC. 9212 COLUMBIA MD
— 443-552 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 443-556 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 COCKEYSVL MD
— 443-572 1XXX2XXX3XXX4XXX6XXX7XXX9XXX · 4 holders which blocks → VERIZON MARYLAND, INC. 9212 GLENBURNIE MD
— 443-612 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 CATONSVL MD
— 443-643 0XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → VERIZON MARYLAND, INC. 9212 BEL AIR MD
— 443-663 0XXX1XXX2XXX3XXX4XXX5XXX7XXX9XXX · 6 holders which blocks → VERIZON MARYLAND, INC. 9212 WOODLAWN MD
— 443-678 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → VERIZON MARYLAND, INC. 9212 PARKVILLE MD
— 443-734 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → VERIZON MARYLAND, INC. 9212 SEVERN MD
— 443-755 2XXX3XXX4XXX5XXX6XXX7XXX · 2 holders which blocks → VERIZON MARYLAND, INC. 9212 WATERLO238 MD
— 443-770 1XXX2XXX3XXX4XXX5XXX6XXX7XXX · 6 holders which blocks → VERIZON MARYLAND, INC. 9212 ARGRGBSNIS MD
— 443-777 0XXX9XXX · 2 holders which blocks → VERIZON MARYLAND, INC. 9212 ESSEX MD
— 443-778 1XXX2XXX9XXX which blocks → VERIZON MARYLAND, INC. 9212 WATERLO236 MD
— 443-841 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → VERIZON MARYLAND, INC. 9212 TOWSON MD
— 443-843 0XXX1XXX2XXX3XXX4XXX9XXX · 4 holders which blocks → VERIZON MARYLAND, INC. 9212 HAVREGRACE MD

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.