NumberResearch Membership · Data 09/20/2026

Recent prefix assignments

0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/20/2026

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 512
SOUTHWESTERN BELL 274
NEW CINGULAR WIRELESS PCS, LLC - IL 98
T-MOBILE USA, INC. 70
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - TX 49
LEVEL 3 OF TELECOM OF TEXAS, LLC - TX 45
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
— 512-531 9XXX which blocks → LEVEL 3 OF TELECOM OF TEXAS, LLC - TX 7516 AUSTIN TX
— 512-532 not yet reported which blocks → LEVEL 3 OF TELECOM OF TEXAS, LLC - TX 7516 AUSTIN TX
— 512-533 2XXX3XXX4XXX5XXX7XXX8XXX9XXX which blocks → LEVEL 3 OF TELECOM OF TEXAS, LLC - TX 7516 AUSTIN TX
— 512-536 0XXX which blocks → SOUTHWESTERN BELL 9533 AUSTIN TX
— 512-538 3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → GRANDE COMMUNICATIONS NETWORKS, INC. - TX 7670 AUSTIN TX
— 512-540 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 LAMPASAS TX
— 512-542 1XXX4XXX which blocks → SOUTHWESTERN BELL 9533 AUSTIN TX
— 512-543 0–9 XXXall 10 · 5 holders which blocks → ONVOY, LLC - TX 903C ROCKDALE TX
— 512-545 0–9 XXXall 10 · 2 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 BASTROP TX
— 512-546 3XXX6XXX7XXX9XXX · 3 holders which blocks → GRANDE COMMUNICATIONS NETWORKS, INC. - TX 7670 DALE/LTNSP TX
— 512-548 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → TWC IP ENABLED SERVICES, LLC 793K LIBERTY HL TX
— 512-554 not yet reported which blocks → T-MOBILE USA, INC. 6529 AUSTIN TX
— 512-555 not yet reported which blocks → MULTIPLE OCN LISTING MULT DIR ASST TX
— 512-556 not yet reported which blocks → SOUTHWESTERN BELL 9533 LAMPASAS TX
— 512-557 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - TX 6506 SAN MARCOS TX
— 512-558 none assigned yet which blocks → BRIGHTSPEED OF SOUTHERN TEXAS, INC. 2140 SAN MARCOS TX
— 512-559 1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → FRONTIER SOUTHWEST INC DBA FRONTIER COMM OF TEXAS 2154 DALE/LTNSP TX
— 512-560 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 AUSTIN TX
— 512-567 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - TX 6506 AUSTIN TX
— 512-569 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - TX 6506 AUSTIN TX
— 512-573 none assigned yet which blocks → T-MOBILE USA, INC. 6529 AUSTIN TX
— 512-576 not yet reported which blocks → T-MOBILE USA, INC. 6529 AUSTIN TX
— 512-581 1XXX5XXX6XXX8XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 BASTROP TX
— 512-582 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLC - TX 903C AUSTIN TX
— 512-583 not yet reported which blocks → LEVEL 3 OF TELECOM OF TEXAS, LLC - TX 7516 AUSTIN TX
— 512-585 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - TX 6506 AUSTIN TX
— 512-589 none assigned yet which blocks → METROPCS, INC. 5562 AUSTIN TX
— 512-591 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - TX 7138 GEORGETOWN TX
— 512-597 2XXX3XXX4XXX7XXX8XXX9XXX which blocks → LEVEL 3 OF TELECOM OF TEXAS, LLC - TX 7516 AUSTIN TX
— 512-599 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLC - TX 903C AUSTIN TX
— 512-600 not yet reported which blocks → GRANDE COMMUNICATIONS NETWORKS, INC. - TX 7670 AUSTIN TX
— 512-601 0XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → FRONTIER SOUTHWEST INC DBA FRONTIER COMM OF TEXAS 2154 DALE/LTNSP TX
— 512-602 not yet reported which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - TX 7138 AUSTIN TX
— 512-603 not yet reported which blocks → SPOK, INC. 6630 AUSTIN TX
— 512-604 not yet reported which blocks → SPOK, INC. 6630 AUSTIN TX
— 512-606 not yet reported which blocks → SPOK, INC. 6630 AUSTIN TX
— 512-607 3XXX4XXX5XXX6XXX7XXX9XXX · 4 holders which blocks → GRANDE COMMUNICATIONS NETWORKS, INC. - TX 7670 DRIPPNGSPG TX
— 512-608 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → SOUTHWESTERN BELL 9533 AUSTIN TX
— 512-609 0XXX1XXX7XXX8XXX9XXX · 4 holders which blocks → SOUTHWESTERN BELL 9533 AUSTIN TX
— 512-610 not yet reported which blocks → ONVOY, LLC - TX 903C AUSTIN TX
— 512-611 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX TX
— 512-613 not yet reported which blocks → SPOK, INC. 6630 AUSTIN TX
— 512-615 not yet reported which blocks → ONVOY, LLC - TX 903C AUSTIN TX
— 512-616 not yet reported which blocks → ONVOY, LLC - TX 903C LEANDER TX
— 512-617 not yet reported which blocks → ONVOY, LLC - TX 903C AUSTIN TX
— 512-618 0XXX1XXX2XXX3XXX4XXX5XXX6XXX which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 SAN MARCOS TX
— 512-620 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → SOUTHWESTERN BELL 9533 LOCKHART TX
— 512-622 not yet reported which blocks → SPOK, INC. 6630 AUSTIN TX
— 512-623 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → SOUTHWESTERN BELL 9533 AUSTIN TX
— 512-624 not yet reported which blocks → SPOK, INC. 6630 AUSTIN TX

Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/20/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.