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
— 573-350 1XXX3XXX4XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → ONVOY, LLC - MO 093F DELTA MO
— 573-351 0XXX2XXX3XXX4XXX6XXX7XXX · 4 holders which blocks → WINDSTREAM MISSOURI, INC. 1885 DONIPHAN MO
— 573-353 none assigned yet which blocks → T-MOBILE USA, INC. 6529 JEFFERSNCY MO
— 573-354 0XXX1XXX4XXX5XXX6XXX8XXX9XXX · 4 holders which blocks → WINDSTREAM MISSOURI, INC. 1885 OXLY MO
— 573-356 0XXX1XXX2XXX which blocks → T-MOBILE USA, INC. 6529 COLUMBIA MO
— 573-357 0XXX6XXX7XXX8XXX · 2 holders which blocks → BPS TELEPHONE COMPANY 0463 PARMA MO
— 573-358 6XXX9XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 BONNETERRE MO
— 573-359 8XXX which blocks → SOUTHWESTERN BELL 9533 HAYTI MO
— 573-360 0–9 XXXall 10 · 7 holders which blocks → CHARTER IP ENABLED SERVICES, LLC 792K E PRAIRIE MO
— 573-361 0XXX1XXX2XXX4XXX5XXX6XXX7XXX9XXX · 6 holders which blocks → ONVOY, LLC - MO 093F ESSEX MO
— 573-362 0–9 XXXall 10 · 7 holders which blocks → ONVOY, LLC - MO 093F FISK MO
— 573-363 0XXX2XXX3XXX4XXX6XXX8XXX · 3 holders which blocks → SOUTHWESTERN BELL 9533 MACKSCREEK MO
— 573-364 not yet reported which blocks → EMBARQ MISSOURI, INC. DBA CENTURYLINK - MO 1811 ROLLA MO
— 573-365 not yet reported which blocks → SOUTHWESTERN BELL 9533 LKOZKOSBCH MO
— 573-366 0–9 XXXall 10 · 2 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 FARMINGTON MO
— 573-368 none assigned yet which blocks → EMBARQ MISSOURI, INC. DBA CENTURYLINK - MO 1811 ROLLA MO
— 573-369 0XXX3XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → SOUTHWESTERN BELL 9533 TUSCUMBIA MO
— 573-370 0–9 XXXall 10 · 8 holders which blocks → PEERLESS NETWORK OF MISSOURI, LLC - MO 225F GIDEON MO
— 573-371 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → PEERLESS NETWORK OF MISSOURI, LLC - MO 225F HOLCOMB MO
— 573-372 0XXX4XXX7XXX8XXX9XXX · 5 holders which blocks → SOUTHWESTERN BELL 9533 GRAVOIS ML MO
— 573-373 0XXX3XXX4XXX7XXX8XXX · 4 holders which blocks → BRIGHTSPEED OF EAST MISSOURI, LLC 1151 LADDONIA MO
— 573-374 not yet reported which blocks → SOUTHWESTERN BELL 9533 GRAVOIS ML MO
— 573-375 2XXX3XXX4XXX5XXX7XXX8XXX9XXX · 5 holders which blocks → UNITED STATES CELLULAR - MO 6275 ELDON MO
— 573-376 0XXX1XXX2XXX3XXX6XXX8XXX9XXX · 4 holders which blocks → ONVOY, LLC - MO 093F HORNERSVL MO
— 573-377 5XXX6XXX7XXX8XXX · 4 holders which blocks → WINDSTREAM MISSOURI, INC. 1885 STOVER MO
— 573-378 not yet reported which blocks → SOUTHWESTERN BELL 9533 VERSAILLES MO
— 573-379 6XXX which blocks → SOUTHWESTERN BELL 9533 PORTAGEVL MO
— 573-380 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 SIKESTON MO
— 573-381 0–9 XXXall 10 · 6 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MO 7218 CAPEGIRARD MO
— 573-382 8XXX which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 CAPEGIRARD MO
— 573-383 0XXX1XXX2XXX3XXX4XXX5XXX6XXX8XXX9XXX · 4 holders which blocks → ONVOY, LLC - MO 093F CANTON MO
— 573-384 2XXX3XXX4XXX7XXX · 2 holders which blocks → WINDSTREAM MISSOURI, INC. 1885 SILEX MO
— 573-385 0XXX1XXX2XXX3XXX4XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → ONVOY, LLC - MO 093F LILBOURN MO
— 573-386 9XXX which blocks → KINGDOM TEL. CO. 1901 AUXVASSE MO
— 573-387 none assigned yet which blocks → KINGDOM TEL. CO. 1901 HATTON MO
— 573-388 0–9 XXXall 10 · 4 holders which blocks → BANDWIDTH.COM CLEC, LLC - MO 993E CAPEGIRARD MO
— 573-389 0XXX1XXX4XXX6XXX7XXX8XXX9XXX · 7 holders which blocks → ONVOY, LLC - MO 093F OAK RIDGE MO
— 573-390 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 OLDAPPLETN MO
— 573-391 0–9 XXXall 10 · 7 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 PORTAGEVL MO
— 573-392 not yet reported which blocks → SOUTHWESTERN BELL 9533 ELDON MO
— 573-393 0XXX3XXX7XXX9XXX · 4 holders which blocks → BRIGHTSPEED OF EAST MISSOURI, LLC 1151 WESTQUINCY MO
— 573-394 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → PEERLESS NETWORK OF MISSOURI, LLC - MO 225F RISCO MO
— 573-395 1XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → EMBARQ MISSOURI, INC. DBA CENTURYLINK - MO 1811 TAOS MO
— 573-396 0XXX3XXX9XXX · 3 holders which blocks → SOUTHWESTERN BELL 9533 RISCO MO
— 573-398 0–9 XXXall 10 · 8 holders which blocks → ONVOY, LLC - MO 093F SCOTT CITY MO
— 573-399 1XXX3XXX4XXX8XXX · 3 holders which blocks → WINDSTREAM MISSOURI, INC. 1885 NAYLOR MO
— 573-400 0XXX2XXX3XXX4XXX5XXX6XXX7XXX · 2 holders which blocks → ONVOY, LLC - MO 093F WESTQUINCY MO
— 573-401 0–9 XXXall 10 · 7 holders which blocks → PEERLESS NETWORK OF MISSOURI, LLC - MO 225F ST MARYS MO
— 573-402 0XXX1XXX2XXX3XXX6XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MO 4932 WARDELL MO
— 573-403 0XXX1XXX2XXX3XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → PEERLESS NETWORK OF MISSOURI, LLC - MO 225F WYATT 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.