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
— 520-297 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-298 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-299 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-304 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 TUCSON AZ
— 520-307 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 TUCSON AZ
— 520-311 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX AZ
— 520-312 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 TUCSON AZ
— 520-315 not yet reported which blocks → GILA RIVER TELECOMM, INC. 2179 CASABLANCA AZ
— 520-316 not yet reported which blocks → QWEST CORPORATION 9636 CASAGRANDE AZ
— 520-318 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-319 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-320 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-321 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-322 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-323 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-324 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-325 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-326 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-327 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-331 not yet reported which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
— 520-335 0–9 XXXall 10 · 3 holders which blocks → COMCAST IP PHONE, LLC 318J SIERRAVIST AZ
— 520-347 0–9 XXXall 10 · 3 holders which blocks → TELNYX LLC 073H TUCSON AZ
— 520-349 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 TUCSON AZ
— 520-352 7XXX9XXX which blocks → ELECTRIC LIGHTWAVE LLC DBA ALLSTREAM 7175 TUCSON AZ
— 520-356 0XXX4XXX5XXX8XXX9XXX · 2 holders which blocks → QWEST CORPORATION 9636 HAYDEN AZ
— 520-357 0XXX1XXX4XXX8XXX9XXX · 3 holders which blocks → QWEST CORPORATION 9636 HAYDEN AZ
— 520-360 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 TUCSON AZ
— 520-361 not yet reported which blocks → TOHONO O'ODHAM UTILITY AUTHORITY 2173 SANTA ROSA AZ
— 520-362 not yet reported which blocks → TOHONO O'ODHAM UTILITY AUTHORITY 2173 W SANSIMON AZ
— 520-363 1XXX2XXX3XXX4XXX6XXX8XXX · 3 holders which blocks → QWEST CORPORATION 9636 HAYDEN AZ
— 520-364 not yet reported which blocks → QWEST CORPORATION 9636 DOUGLAS AZ
— 520-366 1XXX2XXX3XXX4XXX6XXX7XXX8XXX · 4 holders which blocks → QWEST CORPORATION 9636 BISBEE AZ
— 520-370 0XXX which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
— 520-371 3XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → METROPCS, INC. 5562 CASAGRANDE AZ
— 520-374 not yet reported which blocks → QWEST CORPORATION 9636 CASAGRANDE AZ
— 520-375 1XXX2XXX3XXX4XXX9XXX · 4 holders which blocks → QWEST CORPORATION 9636 NOGALES AZ
— 520-377 not yet reported which blocks → QWEST CORPORATION 9636 NOGALES AZ
— 520-378 not yet reported which blocks → QWEST CORPORATION 9636 SIERRAVIST AZ
— 520-379 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLC - AZ 630E DOUGLAS AZ
— 520-381 1XXX4XXX5XXX7XXX9XXX · 2 holders which blocks → ELECTRIC LIGHTWAVE LLC DBA ALLSTREAM 7175 CASAGRANDE AZ
— 520-382 7XXX which blocks → LEVEL 3 TELECOM OF ARIZONA, LLC - AZ 7552 TUCSON AZ
— 520-383 not yet reported which blocks → TOHONO O'ODHAM UTILITY AUTHORITY 2173 SELLS AZ
— 520-384 not yet reported which blocks → QWEST CORPORATION 9636 WILLCOX AZ
— 520-385 5XXX6XXX7XXX · 2 holders which blocks → QWEST CORPORATION 9636 SAN MANUEL AZ
— 520-387 not yet reported which blocks → TABLE TOP TELEPHONE COMPANY 3334 AJO AZ
— 520-388 0XXX which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-390 none assigned yet which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
— 520-391 0–9 XXXall 10 · 5 holders which blocks → ELECTRIC LIGHTWAVE LLC DBA ALLSTREAM 7175 SUPERIOR AZ
— 520-393 3XXX8XXX9XXX · 2 holders which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-394 1XXX3XXX4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → QWEST CORPORATION 9636 NOGALES 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.