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 520
QWEST CORPORATION 201
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 104
T-MOBILE USA, INC. 84
NEW CINGULAR WIRELESS PCS, LLC 53
ONVOY, LLC - AZ 47
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
Clear Download CSV ↓
Recent NPA-NXX prefix assignments
AssignedNPA-NXXThousands-blocks taken (last-4 opening)Code holderOCNRate centerState
2020-09-24 520-755 1XXX5XXX7XXX · 3 holders which blocks → FRACTEL, LLC 965H LONE BUTTE AZ
2020-09-24 520-899 8XXX9XXX · 2 holders which blocks → FRACTEL, LLC 965H MARCOPAVLG AZ
2020-09-16 520-486 0–9 XXXwhole prefix which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 TUCSON AZ
2020-09-01 520-476 0–9 XXXall 10 · 6 holders which blocks → NUSO, LLC 478J TUCSON AZ
2020-06-05 520-475 0–9 XXXall 10 · 5 holders which blocks → CSC WIRELESS, LLC 425J TUCSON AZ
2020-06-02 520-502 0–9 XXXall 10 · 2 holders which blocks → ONVOY, LLC - AZ 630E SASABE AZ
2020-06-02 520-522 2XXX5XXX7XXX · 3 holders which blocks → FRACTEL, LLC 965H CASABLANCA AZ
2020-06-02 520-655 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → FRACTEL, LLC 965H SUPERIOR AZ
2020-05-11 520-479 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
2020-05-07 520-523 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLC - AZ 630E SIERRAVIST AZ
2020-05-07 520-525 0–9 XXXall 10 · 5 holders which blocks → ONVOY, LLC - AZ 630E BISBEE AZ
2020-04-20 520-453 0XXX1XXX2XXX3XXX4XXX5XXX7XXX8XXX9XXX · 5 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 TOMBSTONE AZ
2019-12-19 520-467 0–9 XXXall 10 · 2 holders which blocks → ONVOY, LLC - AZ 630E TUCSON AZ
2019-12-18 520-420 0–9 XXXall 10 · 5 holders which blocks → HD CARRIER LLC 321J TUCSON AZ
2019-12-11 520-386 0–9 XXXall 10 · 5 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 BENSON AZ
2019-10-03 520-436 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLC - AZ 630E HAYDEN AZ
2019-10-03 520-438 0–9 XXXall 10 · 5 holders which blocks → ONVOY, LLC - AZ 630E WHITLOW AZ
2019-09-16 520-416 0–9 XXXall 10 · 5 holders which blocks → EXIANT COMMUNICATIONS LLC 114J TUCSON AZ
2019-08-26 520-472 0–9 XXXall 10 · 5 holders which blocks → QWEST CORPORATION 9636 CASAGRANDE AZ
2019-08-23 520-380 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 CASAGRANDE AZ
2019-08-05 520-372 0–9 XXXall 10 · 4 holders which blocks → COMCAST IP PHONE, LLC 318J TUCSON AZ
2019-04-18 520-493 0–9 XXXwhole prefix which blocks → FIRSTDIGITAL TELECOM, LLC - UT 5727 TUCSON AZ
2019-02-19 520-376 0–9 XXXall 10 · 3 holders which blocks → METROPCS, INC. 5562 SIERRAVIST AZ
2019-02-05 520-783 0–9 XXXall 10 · 4 holders which blocks → METROPCS, INC. 5562 TUCSON AZ
2018-10-29 520-412 0–9 XXXall 10 · 4 holders which blocks → PEERLESS NETWORK OF ARIZONA, LLC - AZ 579F TOMBSTONE AZ
2018-09-21 520-346 0–9 XXXall 10 · 3 holders which blocks → PEERLESS NETWORK OF ARIZONA, LLC - AZ 579F BISBEE AZ
2018-09-10 520-759 0–9 XXXall 10 · 7 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 CASAGRANDE AZ
2018-09-10 520-779 0–9 XXXall 10 · 4 holders which blocks → BANDWIDTH.COM CLEC, LLC - AZ 587F WILLCOX AZ
2017-12-20 520-771 0–9 XXXall 10 · 4 holders which blocks → VONAGE AMERICA LLC 197D TUCSON AZ
2017-10-10 520-600 0–9 XXXall 10 · 5 holders which blocks → ONVOY, LLC - AZ 630E TUCSON AZ
2017-09-12 520-666 0–9 XXXall 10 · 2 holders which blocks → ONVOY, LLC - AZ 630E CASAGRANDE AZ
2017-08-17 520-462 0–9 XXXwhole prefix which blocks → ONVOY, LLC - AZ 630E TUCSON AZ
2017-07-13 520-367 0–9 XXXall 10 · 6 holders which blocks → ONVOY SPECTRUM, LLC 624H TUCSON AZ
2017-06-15 520-849 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 TUCSON AZ
2017-04-28 520-526 0–9 XXXall 10 · 6 holders which blocks → COMMIO, LLC 939H TUCSON AZ
2016-12-09 520-341 0–9 XXXall 10 · 6 holders which blocks → TELNYX LLC 073H NOGALES AZ
2016-10-27 520-354 0–9 XXXall 10 · 5 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 TUCSON AZ
2016-09-14 520-274 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
2016-09-14 520-402 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 BENSON AZ
2016-09-01 520-340 0–9 XXXall 10 · 6 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 CASAGRANDE AZ
2016-07-13 520-317 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLC - AZ 630E HAYDEN AZ
2016-07-06 520-330 0–9 XXXall 10 · 4 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 TUCSON AZ
2016-03-22 520-597 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLC - AZ 630E SUPERIOR AZ
2016-03-14 520-244 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
2016-03-09 520-585 0–9 XXXall 10 · 4 holders which blocks → METROPCS, INC. 5562 TUCSON AZ
2015-12-29 520-217 0–9 XXXall 10 · 4 holders which blocks → QWEST CORPORATION 9636 CASAGRANDE AZ
2015-11-19 520-214 0–9 XXXwhole prefix which blocks → ONVOY, LLC - AZ 630E TUCSON AZ
2015-09-30 520-636 0–9 XXXall 10 · 5 holders which blocks → PEERLESS NETWORK OF ARIZONA, LLC - AZ 579F SAN MANUEL AZ
2015-08-13 520-900 0–9 XXXall 10 · 3 holders which blocks → ONVOY, LLC - AZ 630E TUCSON AZ
2015-07-29 520-589 0–9 XXXall 10 · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON 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.