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 573
SOUTHWESTERN BELL 128
NEW CINGULAR WIRELESS PCS, LLC - IL 113
ONVOY, LLC - MO 86
LEVEL 3 COMMUNICATIONS, LLC - MO 63
T-MOBILE USA, INC. 44
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
2005-04-20 573-915 0–9 XXXall 10 · 2 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 FARMINGTON MO
2005-04-19 573-855 0–9 XXXwhole prefix which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 WAYNESVL MO
2005-03-03 573-838 0–9 XXXall 10 · 4 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 SIKESTON MO
2005-02-11 573-750 7XXX which blocks → LEVEL 3 COMMUNICATIONS, LLC - MO 4932 EUGENE MO
2004-12-30 573-464 3XXX6XXX7XXX · 2 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MO 4932 CALIFORNIA MO
2004-12-30 573-622 0XXX which blocks → LEVEL 3 COMMUNICATIONS, LLC - MO 4932 CLARKSBURG MO
2004-12-17 573-870 1XXX7XXX8XXX · 2 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 VAN BUREN MO
2004-11-09 573-823 0–9 XXXwhole prefix which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 COLUMBIA MO
2004-11-04 573-604 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 WINONA MO
2004-11-04 573-953 2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 BIRCH TREE MO
2004-09-21 573-846 0–9 XXXall 10 · 7 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 PERRYVILLE MO
2004-06-23 573-416 0–9 XXXall 10 · 8 holders which blocks → UNITED STATES CELLULAR - MO 6275 FULTON MO
2004-06-23 573-418 0–9 XXXall 10 · 2 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MO 5814 JEFFERSNCY MO
2004-04-22 573-532 1XXX2XXX5XXX8XXX · 4 holders which blocks → UNITED STATES CELLULAR - MO 6275 DONIPHAN MO
2004-04-06 573-417 1XXX2XXX3XXX6XXX8XXX9XXX · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MO 4932 LINN MO
2004-03-10 573-405 1XXX2XXX3XXX4XXX5XXX6XXX8XXX9XXX · 5 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MO 5814 VIENNA MO
2004-03-10 573-407 none assigned yet which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MO 5814 CROCKER MO
2004-03-10 573-408 none assigned yet which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MO 5814 DIXON MO
2003-11-04 573-285 1XXX2XXX8XXX · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MO 4932 CLARKSBURG MO
2003-06-20 573-330 0–9 XXXwhole prefix which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 FARMINGTON MO
2003-06-03 573-777 0–9 XXXall 10 · 3 holders which blocks → SOCKET TELECOM, LLC - MO 554A COLUMBIA MO
2003-06-03 573-982 0XXX1XXX2XXX3XXX4XXX6XXX7XXX9XXX · 5 holders which blocks → ONVOY, LLC - MO 093F CENTRALIA MO
2003-04-21 573-301 0–9 XXXwhole prefix which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 JEFFERSNCY MO
2003-04-09 573-205 0–9 XXXwhole prefix which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 CUBA MO
2003-04-09 573-300 0–9 XXXall 10 · 2 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 POPLAR BLF MO
2003-02-04 573-326 0–9 XXXall 10 · 6 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MO 5814 MARSTON MO
2003-01-10 573-312 0XXX1XXX2XXX3XXX4XXX5XXX6XXX8XXX9XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MO 4932 ELSBERRY MO
2003-01-10 573-314 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MO 4932 FRANKFORD MO
2003-01-10 573-319 0–9 XXXall 10 · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MO 4932 MACKSCREEK MO
2003-01-10 573-321 0XXX1XXX2XXX3XXX4XXX5XXX7XXX8XXX9XXX · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MO 4932 ADVANCE MO
2003-01-10 573-340 0XXX1XXX2XXX3XXX4XXX5XXX6XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MO 4932 WELLSVILLE MO
2003-01-10 573-342 0–9 XXXall 10 · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MO 4932 RICHWOODS MO
2003-01-10 573-343 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → SOUTHWESTERN BELL 9533 PUXICO MO
2003-01-10 573-349 0XXX1XXX2XXX3XXX4XXX5XXX6XXX8XXX9XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MO 4932 PATTON MO
2003-01-10 573-352 0–9 XXXall 10 · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MO 4932 POCAHONTAS MO
2003-01-09 573-206 0XXX1XXX2XXX3XXX4XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MO 4932 BEAUFORT MO
2003-01-09 573-207 0–9 XXXall 10 · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MO 4932 GRAVOIS ML MO
2003-01-09 573-208 0–9 XXXall 10 · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MO 4932 MARBLEHILL MO
2003-01-09 573-213 0–9 XXXall 10 · 9 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MO 4932 BOWLNGGREN MO
2003-01-09 573-217 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MO 4932 CAMPBELL MO
2003-01-09 573-240 0–9 XXXall 10 · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MO 4932 CENTER MO
2003-01-09 573-250 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MO 4932 CLARKSVL MO
2003-01-09 573-260 0XXX1XXX2XXX3XXX4XXX5XXX6XXX8XXX9XXX · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MO 4932 CLIMAX SPG MO
2003-01-06 573-203 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MO 4932 SENATH MO
2003-01-02 573-202 0XXX1XXX2XXX3XXX4XXX5XXX6XXX8XXX9XXX · 5 holders which blocks → T-MOBILE USA, INC. 6529 ROLLA MO
2002-12-16 573-201 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 ROLLA MO
2002-09-30 573-200 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 CAPEGIRARD MO
2002-08-09 573-595 2XXX5XXX7XXX8XXX · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MO 4932 EUGENE MO
2002-07-23 573-275 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 CAPEGIRARD MO
2002-06-06 573-451 1XXX2XXX3XXX4XXX · 2 holders which blocks → FIDELITY CABLEVISION, LLC 3275 ST ROBERT MO

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.