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 623
QWEST CORPORATION 97
T-MOBILE USA, INC. 39
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 31
ONVOY, LLC - AZ 29
NEW CINGULAR WIRELESS PCS, LLC 22
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
2020-03-05 623-254 0–9 XXXall 10 · 5 holders which blocks → METROPCS, INC. 5562 PHOENIX AZ
2020-03-05 623-663 0–9 XXXwhole prefix which blocks → ONVOY, LLC - AZ 630E PHOENIX AZ
2020-02-20 623-323 0–9 XXXwhole prefix which blocks → ONVOY, LLC - AZ 630E PHOENIX AZ
2020-02-13 623-250 0–9 XXXall 10 · 3 holders which blocks → BANDWIDTH.COM CLEC, LLC - AZ 587F PHOENIX AZ
2020-01-07 623-253 0–9 XXXall 10 · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 PHOENIX AZ
2019-12-19 623-263 0–9 XXXwhole prefix which blocks → ONVOY, LLC - AZ 630E PHOENIX AZ
2019-09-13 623-600 0–9 XXXall 10 · 3 holders which blocks → FRACTEL, LLC 965H PHOENIX AZ
2019-08-26 623-471 0–9 XXXall 10 · 3 holders which blocks → QWEST CORPORATION 9636 PHOENIX AZ
2019-06-14 623-259 0–9 XXXall 10 · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 PHOENIX AZ
2019-03-21 623-526 0–9 XXXwhole prefix which blocks → ONVOY, LLC - AZ 630E PHOENIX AZ
2019-02-14 623-248 0–9 XXXall 10 · 2 holders which blocks → QWEST CORPORATION 9636 PHOENIX AZ
2019-01-14 623-246 0–9 XXXall 10 · 6 holders which blocks → METROPCS, INC. 5562 PHOENIX AZ
2018-11-01 623-401 0–9 XXXwhole prefix which blocks → ONVOY, LLC - AZ 630E PHOENIX AZ
2018-10-02 623-473 0–9 XXXall 10 · 2 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 PHOENIX AZ
2018-08-24 623-244 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLC - AZ 630E PHOENIX AZ
2018-05-25 623-440 0–9 XXXall 10 · 2 holders which blocks → COMCAST IP PHONE, LLC 318J PHOENIX AZ
2018-03-29 623-231 0–9 XXXall 10 · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 PHOENIX AZ
2018-01-17 623-289 0–9 XXXall 10 · 5 holders which blocks → BANDWIDTH.COM CLEC, LLC - AZ 587F PHOENIX AZ
2017-07-13 623-439 0–9 XXXall 10 · 4 holders which blocks → ONVOY SPECTRUM, LLC 624H PHOENIX AZ
2017-04-28 623-404 0–9 XXXall 10 · 3 holders which blocks → CENTURYLINK COMMUNICATIONS, LLC 508J PHOENIX AZ
2017-04-27 623-469 0–9 XXXall 10 · 2 holders which blocks → BANDWIDTH.COM CLEC, LLC - AZ 587F PHOENIX AZ
2016-10-21 623-233 0–9 XXXall 10 · 7 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 PHOENIX AZ
2016-10-19 623-232 0–9 XXXall 10 · 4 holders which blocks → QWEST CORPORATION 9636 PHOENIX AZ
2016-05-10 623-235 0–9 XXXall 10 · 5 holders which blocks → QWEST CORPORATION 9636 PHOENIX AZ
2016-04-21 623-230 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 PHOENIX AZ
2016-03-22 623-213 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 PHOENIX AZ
2016-03-09 623-226 0–9 XXXall 10 · 2 holders which blocks → METROPCS, INC. 5562 PHOENIX AZ
2015-10-27 623-200 0–9 XXXall 10 · 2 holders which blocks → ONVOY, LLC - AZ 630E PHOENIX AZ
2015-09-28 623-745 0–9 XXXall 10 · 4 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 PHOENIX AZ
2015-08-12 623-300 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLC - AZ 630E PHOENIX AZ
2015-06-26 623-228 0–9 XXXwhole prefix which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - AZ 7217 PHOENIX AZ
2015-06-15 623-499 0–9 XXXall 10 · 4 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 PHOENIX AZ
2015-05-29 623-522 0–9 XXXall 10 · 4 holders which blocks → METROPCS, INC. 5562 PHOENIX AZ
2015-05-21 623-285 0–9 XXXall 10 · 3 holders which blocks → QWEST CORPORATION 9636 PHOENIX AZ
2015-03-27 623-296 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 PHOENIX AZ
2015-02-17 623-900 0–9 XXXall 10 · 3 holders which blocks → ONVOY, LLC - AZ 630E PHOENIX AZ
2015-02-11 623-759 0–9 XXXall 10 · 2 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 PHOENIX AZ
2015-01-19 623-219 0–9 XXXall 10 · 3 holders which blocks → METROPCS, INC. 5562 PHOENIX AZ
2015-01-15 623-633 0–9 XXXall 10 · 4 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 PHOENIX AZ
2014-11-13 623-227 0–9 XXXall 10 · 2 holders which blocks → BANDWIDTH.COM CLEC, LLC - AZ 587F PHOENIX AZ
2014-09-19 623-216 0–9 XXXall 10 · 2 holders which blocks → METROPCS, INC. 5562 PHOENIX AZ
2013-10-24 623-800 0–9 XXXall 10 · 2 holders which blocks → ONVOY, LLC - AZ 630E PHOENIX AZ
2013-09-26 623-999 0–9 XXXall 10 · 2 holders which blocks → ONVOY, LLC - AZ 630E PHOENIX AZ
2013-02-05 623-500 0–9 XXXall 10 · 3 holders which blocks → ONVOY, LLC - AZ 630E PHOENIX AZ
2012-11-19 623-666 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLC - AZ 630E PHOENIX AZ
2012-05-23 623-888 0–9 XXXall 10 · 5 holders which blocks → PEERLESS NETWORK OF ARIZONA, LLC - AZ 579F PHOENIX AZ
2012-05-03 623-299 0–9 XXXall 10 · 5 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 PHOENIX AZ
2012-03-05 623-777 0–9 XXXall 10 · 5 holders which blocks → PEERLESS NETWORK OF ARIZONA, LLC - AZ 579F PHOENIX AZ
2012-01-30 623-419 0–9 XXXall 10 · 3 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 PHOENIX AZ
2011-10-04 623-282 0–9 XXXall 10 · 4 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 PHOENIX AZ

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.