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 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
2021-09-08 573-935 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 DEXTER MO
2021-08-27 573-601 0XXX1XXX2XXX5XXX7XXX8XXX9XXX · 5 holders which blocks → T-MOBILE USA, INC. 6529 KENNETT MO
2021-07-26 573-740 0XXX1XXX2XXX3XXX4XXX5XXX6XXX · 3 holders which blocks → BANDWIDTH.COM CLEC, LLC - MO 993E BENTON MO
2021-06-25 573-704 0XXX4XXX5XXX · 2 holders which blocks → ONVOY, LLC - MO 093F IRONTON MO
2021-06-25 573-706 0XXX1XXX6XXX7XXX8XXX · 3 holders which blocks → ONVOY, LLC - MO 093F WELLSVILLE MO
2021-06-17 573-602 0–9 XXXall 10 · 5 holders which blocks → ONVOY, LLC - MO 093F ELDON MO
2021-06-04 573-580 0–9 XXXall 10 · 3 holders which blocks → ONVOY SPECTRUM, LLC 624H BELLE MO
2021-05-10 573-804 0XXX1XXX2XXX3XXX8XXX9XXX · 4 holders which blocks → TELNYX LLC 073H SENATH MO
2021-03-16 573-801 0–9 XXXall 10 · 3 holders which blocks → STRATUS NETWORKS 495J COLUMBIA MO
2021-03-12 573-781 0XXX1XXX3XXX4XXX7XXX8XXX9XXX · 4 holders which blocks → ONVOY, LLC - MO 093F CLIMAX SPG MO
2021-03-12 573-831 0XXX3XXX · 2 holders which blocks → ONVOY, LLC - MO 093F CALEDONIA MO
2021-03-12 573-867 0XXX1XXX2XXX3XXX5XXX7XXX8XXX9XXX · 5 holders which blocks → ONVOY, LLC - MO 093F ELSBERRY MO
2021-03-12 573-913 0XXX1XXX5XXX7XXX8XXX · 4 holders which blocks → ONVOY, LLC - MO 093F BLOOMSDALE MO
2021-03-12 573-936 0XXX1XXX3XXX4XXX5XXX6XXX7XXX9XXX · 4 holders which blocks → ONVOY, LLC - MO 093F MEXICO MO
2021-03-12 573-956 0XXX1XXX5XXX8XXX · 3 holders which blocks → ONVOY, LLC - MO 093F MONTGORYCY MO
2021-02-23 573-871 2XXX7XXX which blocks → ONVOY, LLC - MO 093F HERMANN MO
2021-02-18 573-907 0XXX1XXX2XXX5XXX · 4 holders which blocks → ONVOY, LLC - MO 093F ST THOMAS MO
2021-02-18 573-972 0XXX2XXX3XXX7XXX8XXX · 4 holders which blocks → ONVOY, LLC - MO 093F META MO
2021-02-05 573-952 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 FLAT RIVER MO
2021-02-01 573-810 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLC - MO 093F COLUMBIA MO
2021-02-01 573-812 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → ONVOY, LLC - MO 093F CUBA MO
2021-02-01 573-909 0XXX1XXX2XXX3XXX9XXX · 4 holders which blocks → ONVOY, LLC - MO 093F NEWBLOMFLD MO
2021-01-20 573-650 0–9 XXXall 10 · 7 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MO 5814 POTOSI MO
2020-12-02 573-852 0XXX1XXX2XXX3XXX · 3 holders which blocks → IP HORIZON LLC 515J LINN MO
2020-11-24 573-613 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 FULTON MO
2020-11-12 573-617 0XXX4XXX7XXX8XXX9XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 SULLIVAN MO
2020-11-12 573-661 0XXX1XXX2XXX4XXX6XXX7XXX9XXX · 5 holders which blocks → T-MOBILE USA, INC. 6529 BOWLNGGREN MO
2020-10-20 573-993 0XXX3XXX4XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → ONVOY, LLC - MO 093F CLARKSVL MO
2020-10-19 573-572 0XXX2XXX3XXX · 2 holders which blocks → ONVOY, LLC - MO 093F LEASBURG MO
2020-10-19 573-877 7XXX8XXX which blocks → ONVOY, LLC - MO 093F VICHY MO
2020-10-01 573-973 1XXX2XXX3XXX6XXX7XXX8XXX · 3 holders which blocks → ONVOY, LLC - MO 093F EOLIA MO
2020-09-08 573-630 0–9 XXXall 10 · 4 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MO 6123 BONNETERRE MO
2020-05-21 573-540 0–9 XXXall 10 · 6 holders which blocks → CSC WIRELESS, LLC 425J COLUMBIA MO
2020-04-03 573-932 0XXX1XXX2XXX3XXX4XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → UNITED STATES CELLULAR - MO 6275 CAMDENTON MO
2020-03-09 573-536 0–9 XXXall 10 · 4 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 TAOS MO
2019-12-18 573-530 0–9 XXXall 10 · 5 holders which blocks → TELNYX LLC 073H COLUMBIA MO
2019-10-25 573-946 0XXX1XXX3XXX6XXX · 4 holders which blocks → FRACTEL, LLC 965H POCAHONTAS MO
2019-08-01 573-666 0XXX1XXX2XXX6XXX9XXX · 5 holders which blocks → FRACTEL, LLC 965H BOWLNGGREN MO
2019-08-01 573-800 0XXX1XXX2XXX3XXX4XXX5XXX7XXX8XXX9XXX · 4 holders which blocks → FRACTEL, LLC 965H CENTER MO
2019-08-01 573-900 0–9 XXXall 10 · 7 holders which blocks → FRACTEL, LLC 965H PERRYVILLE MO
2019-06-26 573-813 0XXX1XXX3XXX4XXX6XXX8XXX9XXX · 7 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MO 6123 E PRAIRIE MO
2019-03-04 573-843 0XXX1XXX2XXX3XXX4XXX5XXX6XXX8XXX · 5 holders which blocks → T-MOBILE USA, INC. 6529 CARUTHRSVL MO
2018-12-20 573-753 0XXX which blocks → CHARTER IP ENABLED SERVICES, LLC 792K STEELVILLE MO
2018-12-20 573-849 0XXX which blocks → CHARTER IP ENABLED SERVICES, LLC 792K FARBER MO
2018-12-03 573-516 0–9 XXXall 10 · 4 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MO 5814 FLAT RIVER MO
2018-11-13 573-527 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLC - MO 093F BIRCH TREE MO
2018-10-31 573-507 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 COLUMBIA MO
2018-09-27 573-510 0–9 XXXall 10 · 4 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 JACKSON MO
2018-05-08 573-910 0–9 XXXall 10 · 4 holders which blocks → AIRESPRING, INC. 996H FARMINGTON MO
2017-11-02 573-506 0XXX2XXX · 2 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MO 4932 TEBBETTS MO

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.