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
— 520-209 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-211 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX AZ
— 520-212 not yet reported which blocks → MIDVALE TELEPHONE EXCHANGE, INC. 2226 CASCABEL AZ
— 520-215 not yet reported which blocks → GILA RIVER TELECOMM, INC. 2179 BLACKWATER AZ
— 520-216 2XXX3XXX4XXX5XXX6XXX7XXX9XXX · 3 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 NOGALES AZ
— 520-218 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-219 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-224 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 7 holders which blocks → ELECTRIC LIGHTWAVE LLC DBA ALLSTREAM 7175 SIERRAVIST AZ
— 520-225 0XXX7XXX8XXX9XXX · 2 holders which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-228 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-229 7XXX which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-230 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 TUCSON AZ
— 520-231 0–9 XXXall 10 · 5 holders which blocks → BANDWIDTH.COM CLEC, LLC - AZ 587F WHITLOW AZ
— 520-232 2XXX3XXX4XXX · 3 holders which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-233 0–9 XXXall 10 · 5 holders which blocks → ONVOY, LLC - AZ 630E CASAGRANDE AZ
— 520-235 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 TUCSON AZ
— 520-237 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 TUCSON AZ
— 520-238 none assigned yet which blocks → T-MOBILE USA, INC. 6529 YUMA AZ
— 520-239 6XXX9XXX · 2 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - AZ 7217 TUCSON AZ
— 520-240 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 TUCSON AZ
— 520-241 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 TUCSON AZ
— 520-243 0–9 XXXall 10 · 3 holders which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-245 not yet reported which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
— 520-248 6XXX7XXX which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
— 520-249 none assigned yet which blocks → T-MOBILE USA, INC. 6529 SIERRAVIST AZ
— 520-250 2XXX3XXX which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
— 520-251 4XXX5XXX7XXX8XXX9XXX · 4 holders which blocks → T-MOBILE USA, INC. 6529 CASAGRANDE AZ
— 520-252 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → T-MOBILE USA, INC. 6529 CASAGRANDE AZ
— 520-258 1XXX2XXX3XXX8XXX9XXX which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-259 not yet reported which blocks → NORTH COUNTY COMMUNICATIONS CORPORATION 8293 TUCSON AZ
— 520-260 5XXX7XXX8XXX9XXX which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 TUCSON AZ
— 520-263 0–9 XXXall 10 · 5 holders which blocks → COMCAST IP PHONE, LLC 318J SIERRAVIST AZ
— 520-264 0–9 XXXall 10 · 7 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 NOGALES AZ
— 520-267 not yet reported which blocks → NORTH COUNTY COMMUNICATIONS CORPORATION 8293 SIERRAVIST AZ
— 520-270 not yet reported which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
— 520-271 0XXX which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
— 520-272 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 TUCSON AZ
— 520-275 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 TUCSON AZ
— 520-280 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 CASAGRANDE AZ
— 520-281 not yet reported which blocks → QWEST CORPORATION 9636 NOGALES AZ
— 520-282 0–9 XXXall 10 · 6 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 TUCSON AZ
— 520-285 1XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → QWEST CORPORATION 9636 NOGALES AZ
— 520-287 not yet reported which blocks → QWEST CORPORATION 9636 NOGALES AZ
— 520-290 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-291 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-292 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-293 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-294 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-295 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-296 not yet reported which blocks → QWEST CORPORATION 9636 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.