NumberResearch Membership · Data 09/19/2026

Recent prefix assignments

0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/19/2026

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
PAETEC ITEL, LLC 153
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 121
OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 94
NEW CINGULAR WIRELESS PCS, LLC - DC 71
LEVEL 3 COMMUNICATIONS, LLC - MD 69
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
— 443-524 not yet reported which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BALTIMORE MD
— 443-526 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → PAETEC ITEL, LLC 829J HAVREGRACE MD
— 443-528 none assigned yet which blocks → OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 6855 BEL AIR MD
— 443-530 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 6 holders which blocks → PAETEC ITEL, LLC 829J DUNDALK MD
— 443-532 2XXX3XXX9XXX · 3 holders which blocks → METROPCS, INC. 5562 PRINCEFRCK MD
— 443-533 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 6 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 JARRETTSVL MD
— 443-535 1XXX2XXX3XXX4XXX5XXX6XXX7XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 COLUMBIA MD
— 443-536 0XXX2XXX4XXX7XXX8XXX · 2 holders which blocks → METROPCS, INC. 5562 WESTMINSTR MD
— 443-537 0–9 XXXall 10 · 5 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 COLUMBIA MD
— 443-539 4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → PAETEC ITEL, LLC 829J COLUMBIA MD
— 443-540 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 BALTIMORE MD
— 443-541 4XXX5XXX6XXX7XXX · 3 holders which blocks → PAETEC ITEL, LLC 829J COCKEYSVL MD
— 443-542 1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → COMCAST IP PHONE, LLC 318J 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
— 443-548 3XXX which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 PIKESVILLE MD
— 443-549 4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → PAETEC ITEL, LLC 829J DUNDALK MD
— 443-550 0–9 XXXall 10 · 8 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 NORTHBEACH MD
— 443-551 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 WOODLAWN MD
— 443-552 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → VERIZON MARYLAND, INC. 9212 BALTIMORE MD
— 443-553 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 ELKTON MD
— 443-555 not yet reported which blocks → MULTIPLE OCN LISTING MULT DIR ASST MD
— 443-556 not yet reported which blocks → VERIZON MARYLAND, INC. 9212 COCKEYSVL MD
— 443-557 3XXX8XXX · 2 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 GLENBURNIE MD
— 443-559 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → COMCAST IP PHONE, LLC 318J ESSEX MD
— 443-561 4XXX5XXX6XXX7XXX8XXX · 2 holders which blocks → PAETEC ITEL, LLC 829J ELKRIDGE MD
— 443-562 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 BALTIMORE MD
— 443-564 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 TOWSON MD
— 443-567 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 BEL AIR MD
— 443-568 3XXX6XXX7XXX8XXX · 4 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 ARBUTUS MD
— 443-569 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 ANNAPOLIS MD
— 443-570 not yet reported which blocks → OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 6855 BALTIMORE MD
— 443-572 1XXX2XXX3XXX4XXX6XXX7XXX9XXX · 4 holders which blocks → VERIZON MARYLAND, INC. 9212 GLENBURNIE MD
— 443-573 5XXX7XXX · 2 holders which blocks → PAETEC ITEL, LLC 829J BALTIMORE MD
— 443-574 4XXX5XXX6XXX7XXX8XXX · 2 holders which blocks → PAETEC ITEL, LLC 829J ELLICOTTCY MD
— 443-577 4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → PAETEC ITEL, LLC 829J GLENBURNIE MD
— 443-578 1XXX2XXX3XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → XO MARYLAND, LLC 4773 COCKEYSVL MD
— 443-579 4XXX5XXX6XXX7XXX8XXX · 2 holders which blocks → PAETEC ITEL, LLC 829J ESSEX MD
— 443-581 0–9 XXXall 10 · 5 holders which blocks → ONVOY, LLC - MD 876D CHASE MD
— 443-582 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → PAETEC ITEL, LLC 829J CHURCHVL MD
— 443-583 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → PAETEC ITEL, LLC 829J COLUMBIA MD
— 443-584 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → PAETEC ITEL, LLC 829J CROFTON MD
— 443-585 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → PAETEC ITEL, LLC 829J DARLINGTON MD
— 443-586 0–9 XXXall 10 · 3 holders which blocks → CORE COMMUNICATIONS, INC.- MD 2593 DUNDALK MD
— 443-587 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → PAETEC ITEL, LLC 829J EDGEWOOD MD
— 443-588 3XXX6XXX8XXX · 3 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 PARKVILLE MD
— 443-589 4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → PAETEC ITEL, LLC 829J COCKEYSVL MD
— 443-590 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MD 6119 REISTERSTN MD
— 443-592 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → CORE COMMUNICATIONS, INC.- MD 2593 ELKRIDGE MD
— 443-593 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → PAETEC ITEL, LLC 829J ELKTON MD

Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/19/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.