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
— 573-404 0XXX1XXX2XXX3XXX4XXX5XXX8XXX · 5 holders which blocks → ONVOY, LLC - MO 093F QULIN MO
— 573-406 none assigned yet which blocks → SOUTHWESTERN BELL 9533 HANNIBAL MO
— 573-411 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX MO
— 573-413 0–9 XXXall 10 · 5 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 POPLAR BLF MO
— 573-414 0–9 XXXall 10 · 7 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 DEXTER MO
— 573-415 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MO 4932 JEFFERSNCY MO
— 573-419 0–9 XXXall 10 · 7 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 CHAFFEE MO
— 573-421 3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 DEXTER MO
— 573-422 4XXX5XXX8XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 VIENNA MO
— 573-423 0–9 XXXall 10 · 6 holders which blocks → ONVOY, LLC - MO 093F BELLEVIEW MO
— 573-424 none assigned yet which blocks → T-MOBILE USA, INC. 6529 COLUMBIA MO
— 573-425 0XXX2XXX3XXX4XXX5XXX6XXX7XXX · 5 holders which blocks → ONVOY, LLC - MO 093F HUNNEWELL MO
— 573-426 0XXX4XXX7XXX · 2 holders which blocks → FIDELITY CABLEVISION, LLC 3275 ROLLA MO
— 573-427 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 CHARLESTON MO
— 573-429 9XXX which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 POPLAR BLF MO
— 573-431 not yet reported which blocks → SOUTHWESTERN BELL 9533 FLAT RIVER MO
— 573-432 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → ONVOY, LLC - MO 093F IRONTON MO
— 573-434 3XXX7XXX8XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 LKOZKOSBCH MO
— 573-435 2XXX3XXX4XXX5XXX8XXX · 3 holders which blocks → BRIGHTSPEED OF EAST MISSOURI, LLC 1151 EDGAR SPG MO
— 573-436 3XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → BRIGHTSPEED OF EAST MISSOURI, LLC 1151 POTOSI MO
— 573-437 0XXX which blocks → FIDELITY TELEPHONE, LLC 1882 OWENSVILLE MO
— 573-438 not yet reported which blocks → BRIGHTSPEED OF EAST MISSOURI, LLC 1151 POTOSI MO
— 573-439 not yet reported which blocks → MARK TWAIN RURAL TEL. CO. 1914 PHILA MO
— 573-440 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 7 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MO 5814 FREDERCKTN MO
— 573-441 not yet reported which blocks → BRIGHTSPEED OF MISSOURI, LLC 9784 COLUMBIA MO
— 573-442 not yet reported which blocks → BRIGHTSPEED OF MISSOURI, LLC 9784 COLUMBIA MO
— 573-443 not yet reported which blocks → BRIGHTSPEED OF MISSOURI, LLC 9784 COLUMBIA MO
— 573-444 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MO 5814 FREDERCKTN MO
— 573-445 not yet reported which blocks → BRIGHTSPEED OF MISSOURI, LLC 9784 COLUMBIA MO
— 573-446 not yet reported which blocks → BRIGHTSPEED OF MISSOURI, LLC 9784 COLUMBIA MO
— 573-447 6XXX7XXX8XXX9XXX · 3 holders which blocks → BRIGHTSPEED OF MISSOURI, LLC 9784 COLUMBIA MO
— 573-448 0XXX4XXX6XXX7XXX · 4 holders which blocks → SOUTHWESTERN BELL 9533 GIDEON MO
— 573-449 not yet reported which blocks → BRIGHTSPEED OF MISSOURI, LLC 9784 COLUMBIA MO
— 573-450 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 CAPEGIRARD MO
— 573-454 0–9 XXXall 10 · 8 holders which blocks → BANDWIDTH.COM CLEC, LLC - MO 993E FLAT RIVER MO
— 573-455 0XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → SOUTHWESTERN BELL 9533 WESTPHALIA MO
— 573-457 7XXX which blocks → FIDELITY TELEPHONE, LLC 1882 SPRING BLF MO
— 573-458 1XXX3XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → EMBARQ MISSOURI, INC. DBA CENTURYLINK - MO 1811 ROLLA MO
— 573-459 5XXX9XXX which blocks → FIDELITY TELEPHONE, LLC 1882 LYON MO
— 573-461 not yet reported which blocks → ELLINGTON TEL. CO. 1874 CLEARWATER MO
— 573-462 1XXX2XXX3XXX7XXX8XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 JEFFERSNCY MO
— 573-463 0XXX1XXX2XXX3XXX4XXX5XXX6XXX8XXX · 4 holders which blocks → ONVOY, LLC - MO 093F BUNKER MO
— 573-465 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MO 5814 ROLLA MO
— 573-466 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MO 5814 ROLLA MO
— 573-467 4XXX which blocks → T-MOBILE USA, INC. 6529 ROLLA MO
— 573-468 0XXX which blocks → FIDELITY TELEPHONE, LLC 1882 SULLIVAN MO
— 573-470 none assigned yet which blocks → UNITED STATES CELLULAR - MO 6275 BOWLNGGREN MO
— 573-471 not yet reported which blocks → SOUTHWESTERN BELL 9533 SIKESTON MO
— 573-472 not yet reported which blocks → SOUTHWESTERN BELL 9533 SIKESTON MO
— 573-473 none assigned yet which blocks → SOUTHWESTERN BELL 9533 MEXICO 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.