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 501
SOUTHWESTERN BELL 165
NEW CINGULAR WIRELESS PCS, LLC - IL 86
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AR 54
LEVEL 3 COMMUNICATIONS, LLC - AR 48
T-MOBILE USA, INC. 42
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
2019-09-17 501-710 0–9 XXXall 10 · 3 holders which blocks → ONVOY SPECTRUM, LLC 624H LITTLEROCK AR
2019-08-05 501-369 0–9 XXXall 10 · 4 holders which blocks → EXIANT COMMUNICATIONS LLC 114J LITTLEROCK AR
2019-06-12 501-363 0–9 XXXall 10 · 2 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - AR 802C HOTSPRINGS AR
2019-06-11 501-361 0–9 XXXall 10 · 4 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - AR 802C BRYANTCGVL AR
2019-03-28 501-338 1XXX2XXX3XXX8XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - AR 5179 BISMARCK AR
2019-03-28 501-356 0–9 XXXall 10 · 6 holders which blocks → CSC WIRELESS, LLC 425J JESSIEVL AR
2019-03-28 501-357 2XXX which blocks → LEVEL 3 COMMUNICATIONS, LLC - AR 5179 DONALDSON AR
2019-02-12 501-298 0–9 XXXall 10 · 3 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 SPRINGLAKE AR
2019-01-22 501-900 0–9 XXXall 10 · 3 holders which blocks → TERRA NOVA TELECOM INC. 145J LITTLEROCK AR
2018-10-15 501-601 0–9 XXXall 10 · 6 holders which blocks → ONVOY, LLC - AR 348F MALVERN AR
2018-09-21 501-300 0–9 XXXall 10 · 2 holders which blocks → ONVOY, LLC - AR 348F BRADFORD AR
2018-09-21 501-506 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLC - AR 348F GRIFFITHVL AR
2018-09-21 501-600 0–9 XXXall 10 · 6 holders which blocks → ONVOY, LLC - AR 348F PLEASANTPL AR
2018-08-23 501-290 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 SEARCY AR
2018-07-24 501-274 0–9 XXXall 10 · 4 holders which blocks → TELNYX LLC 073H LITTLEROCK AR
2018-03-21 501-273 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 CONWAY AR
2018-01-15 501-271 0–9 XXXall 10 · 3 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 PALARM AR
2017-12-18 501-263 0–9 XXXall 10 · 6 holders which blocks → VONAGE AMERICA LLC 197D LITTLEROCK AR
2017-09-28 501-500 0–9 XXXall 10 · 3 holders which blocks → ONVOY, LLC - AR 348F LITTLEROCK AR
2017-08-11 501-236 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 SEARCY AR
2017-07-19 501-214 0–9 XXXall 10 · 4 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - AR 802C LITTLEROCK AR
2017-03-06 501-293 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 HOTSPRINGS AR
2016-08-18 501-435 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 LITTLEROCK AR
2016-08-18 501-443 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 BENTON AR
2016-03-28 501-424 0–9 XXXall 10 · 4 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 CABOT AR
2015-10-06 501-575 0–9 XXXall 10 · 5 holders which blocks → BANDWIDTH.COM CLEC, LLC - AR 196F BENTON AR
2015-10-01 501-585 0–9 XXXall 10 · 7 holders which blocks → WINDSTREAM COMMUNICATIONS, INC. - AR 7656 CONWAY AR
2015-09-17 501-406 0–9 XXXall 10 · 7 holders which blocks → AIRUS, INC. - AR 578H LITTLEROCK AR
2015-06-30 501-254 0–9 XXXall 10 · 6 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 SEARCY AR
2015-06-24 501-417 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 2 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - AR 5179 JUDSONIA AR
2015-06-19 501-808 0–9 XXXall 10 · 6 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 VILONIA AR
2015-03-25 501-800 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLC - AR 348F PALARM AR
2015-03-25 501-904 0–9 XXXall 10 · 5 holders which blocks → ONVOY, LLC - AR 348F LITTLEROCK AR
2015-02-26 501-478 0–9 XXXall 10 · 5 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 LITTLEROCK AR
2015-01-28 501-777 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLC - AR 348F LITTLEROCK AR
2015-01-21 501-419 0XXX1XXX2XXX3XXX4XXX7XXX9XXX · 5 holders which blocks → CENTURYLINK COMMUNICATIONS, LLC 508J ROSE BUD AR
2015-01-13 501-509 0–9 XXXall 10 · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - AR 5179 COY AR
2014-12-10 501-510 0–9 XXXall 10 · 7 holders which blocks → T-MOBILE USA, INC. 6529 LONOKE AR
2014-08-20 501-502 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 LITTLEROCK AR
2014-08-12 501-508 0–9 XXXall 10 · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - AR 5179 LITTLEROCK AR
2014-08-07 501-503 0–9 XXXall 10 · 4 holders which blocks → BANDWIDTH.COM CLEC, LLC - AR 196F LITTLEROCK AR
2014-03-28 501-415 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 LONOKE AR
2014-03-19 501-507 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 BENTON AR
2014-01-30 501-703 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 LONOKE AR
2012-11-01 501-404 0–9 XXXall 10 · 4 holders which blocks → NUSO, LLC 551G LITTLEROCK AR
2012-11-01 501-420 1XXX2XXX3XXX4XXX5XXX6XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 LITTLEROCK AR
2012-04-17 501-408 0–9 XXXall 10 · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - AR 5179 BENTON AR
2011-12-12 501-712 0–9 XXXall 10 · 3 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 LITTLEROCK AR
2011-11-14 501-331 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 7 holders which blocks → WINDSTREAM ARKANSAS, INC. 1691 PERRYVILLE AR
2011-11-14 501-402 0XXX1XXX2XXX3XXX4XXX8XXX9XXX · 6 holders which blocks → WINDSTREAM ARKANSAS, INC. 1691 GREENBRIER AR

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.