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
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Recent NPA-NXX prefix assignments
AssignedNPA-NXXThousands-blocks taken (last-4 opening)Code holderOCNRate centerState
2021-10-25 520-605 0–9 XXXall 10 · 2 holders which blocks → BANDWIDTH.COM CLEC, LLC - AZ 587F TUCSON AZ
2021-10-15 520-699 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → FRACTEL, LLC 965H SIERRAVIST AZ
2021-10-11 520-598 0–9 XXXall 10 · 6 holders which blocks → METROPCS, INC. 5562 CASAGRANDE AZ
2021-10-04 520-592 0–9 XXXall 10 · 4 holders which blocks → TELNYX LLC 073H NOGALES AZ
2021-09-24 520-587 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 PORTAL AZ
2021-09-15 520-688 0–9 XXXall 10 · 4 holders which blocks → FRACTEL, LLC 965H CASAGRANDE AZ
2021-09-03 520-563 0XXX1XXX2XXX3XXX4XXX5XXX6XXX8XXX9XXX · 4 holders which blocks → IP HORIZON LLC 515J BENSON AZ
2021-09-03 520-564 0–9 XXXall 10 · 4 holders which blocks → IP HORIZON LLC 515J DOUGLAS AZ
2021-09-03 520-567 0–9 XXXall 10 · 4 holders which blocks → IP HORIZON LLC 515J HAYDEN AZ
2021-09-03 520-569 0–9 XXXall 10 · 4 holders which blocks → IP HORIZON LLC 515J SAN MANUEL AZ
2021-09-03 520-581 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → IP HORIZON LLC 515J TOMBSTONE AZ
2021-09-03 520-583 0–9 XXXall 10 · 6 holders which blocks → IP HORIZON LLC 515J WHITLOW AZ
2021-08-24 520-556 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 SIERRAVIST AZ
2021-08-09 520-554 0–9 XXXwhole prefix which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 TUCSON AZ
2021-08-09 520-565 0–9 XXXwhole prefix which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 TUCSON AZ
2021-08-04 520-542 0–9 XXXall 10 · 2 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2021-07-19 520-553 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 CASAGRANDE AZ
2021-07-07 520-541 0–9 XXXall 10 · 4 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 WILLCOX AZ
2021-07-01 520-482 0–9 XXXall 10 · 3 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 TUCSON AZ
2021-06-28 520-580 0–9 XXXall 10 · 3 holders which blocks → ONVOY SPECTRUM, LLC 624H SUPERIOR AZ
2021-05-14 520-543 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
2021-04-12 520-517 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 SACATON AZ
2021-04-06 520-934 0–9 XXXall 10 · 2 holders which blocks → TON80 COMMUNICATIONS, LLC 516J TUCSON AZ
2021-04-02 520-504 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 SIERRAVIST AZ
2021-03-04 520-537 0–9 XXXall 10 · 4 holders which blocks → IP HORIZON LLC 515J TUCSON AZ
2021-02-01 520-910 0–9 XXXall 10 · 2 holders which blocks → ONVOY, LLC - AZ 630E TUCSON AZ
2021-01-11 520-534 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
2020-12-24 520-593 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → ONVOY, LLC - AZ 630E HAYDEN AZ
2020-12-23 520-506 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLC - AZ 630E TOMBSTONE AZ
2020-12-23 520-532 0–9 XXXall 10 · 2 holders which blocks → ONVOY, LLC - AZ 630E CASAGRANDE AZ
2020-12-23 520-637 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 CASAGRANDE AZ
2020-12-22 520-503 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLC - AZ 630E WILLCOX AZ
2020-12-22 520-527 0–9 XXXall 10 · 3 holders which blocks → ONVOY, LLC - AZ 630E BENSON AZ
2020-12-22 520-536 0–9 XXXall 10 · 5 holders which blocks → ONVOY, LLC - AZ 630E DOUGLAS AZ
2020-12-21 520-524 0–9 XXXall 10 · 2 holders which blocks → ONVOY, LLC - AZ 630E TUCSON AZ
2020-12-08 520-535 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
2020-11-23 520-473 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 SIERRAVIST AZ
2020-10-30 520-246 0–9 XXXall 10 · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 TUCSON AZ
2020-10-29 520-650 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLC - AZ 630E WHITLOW AZ
2020-10-27 520-478 0XXX1XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - AZ 7217 AJO AZ
2020-10-26 520-521 0–9 XXXall 10 · 6 holders which blocks → HD CARRIER LLC 321J SAN MANUEL AZ
2020-10-22 520-501 0–9 XXXall 10 · 2 holders which blocks → TWILIO INTERNATIONAL, INC. 506J TUCSON AZ
2020-10-19 520-758 6XXX which blocks → FRACTEL, LLC 965H BLACKWATER AZ
2020-10-19 520-966 3XXX6XXX9XXX · 3 holders which blocks → FRACTEL, LLC 965H SILVERBELL AZ
2020-10-07 520-496 0–9 XXXall 10 · 2 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 TUCSON AZ
2020-10-07 520-497 0–9 XXXall 10 · 2 holders which blocks → BANDWIDTH.COM CLEC, LLC - AZ 587F TUCSON AZ
2020-10-06 520-492 0–9 XXXall 10 · 2 holders which blocks → COMCAST IP PHONE, LLC 318J TUCSON AZ
2020-10-02 520-530 0–9 XXXall 10 · 2 holders which blocks → ONVOY, LLC - AZ 630E TUCSON AZ
2020-09-24 520-588 5XXX8XXX · 2 holders which blocks → FRACTEL, LLC 965H CASCABEL AZ
2020-09-24 520-644 4XXX6XXX · 2 holders which blocks → FRACTEL, LLC 965H KOMATKE 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.