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 817
SOUTHWESTERN BELL 302
NEW CINGULAR WIRELESS PCS, LLC - IL 88
T-MOBILE USA, INC. 54
LEVEL 3 COMMUNICATIONS, LLC - TX 45
ONVOY, LLC - TX 43
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
— 817-563 not yet reported which blocks → SOUTHWESTERN BELL 9533 KENNEDALE TX
— 817-564 1XXX2XXX3XXX4XXX5XXX6XXX8XXX which blocks → PAETEC ITEL, LLC 829J GLENDALE TX
— 817-565 0–9 XXXall 10 · 2 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 WEATHERFD TX
— 817-566 2XXX3XXX4XXX5XXX6XXX8XXX · 3 holders which blocks → PAETEC ITEL, LLC 829J FORT WORTH TX
— 817-568 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-569 0XXX6XXX9XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-570 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-571 not yet reported which blocks → SOUTHWESTERN BELL 9533 EULESS TX
— 817-572 8XXX which blocks → SOUTHWESTERN BELL 9533 KENNEDALE TX
— 817-573 not yet reported which blocks → SOUTHWESTERN BELL 9533 GRANBURY TX
— 817-574 3XXX which blocks → LEVEL 3 OF TELECOM OF TEXAS, LLC - TX 7516 EULESS TX
— 817-575 7XXX9XXX which blocks → LEVEL 3 OF TELECOM OF TEXAS, LLC - TX 7516 ARLINGTON TX
— 817-577 not yet reported which blocks → SOUTHWESTERN BELL 9533 NRICHLDHLS TX
— 817-578 6XXX which blocks → SOUTHWESTERN BELL 9533 GRANBURY TX
— 817-579 not yet reported which blocks → SOUTHWESTERN BELL 9533 GRANBURY TX
— 817-580 1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → SOUTHWESTERN BELL 9533 ATLAS TX
— 817-581 not yet reported which blocks → SOUTHWESTERN BELL 9533 NRICHLDHLS TX
— 817-585 0XXX1XXX2XXX3XXX4XXX5XXX6XXX8XXX9XXX · 3 holders which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-587 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLC - TX 903C ALVARADO TX
— 817-588 not yet reported which blocks → SOUTHWESTERN BELL 9533 ARLINGTON TX
— 817-589 not yet reported which blocks → SOUTHWESTERN BELL 9533 ATLAS TX
— 817-590 7XXX which blocks → SOUTHWESTERN BELL 9533 ATLAS TX
— 817-592 0–9 XXXall 10 · 4 holders which blocks → AT&T ENTERPRISES, LLC 516C MANSFIELD TX
— 817-593 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-594 not yet reported which blocks → SOUTHWESTERN BELL 9533 WEATHERFD TX
— 817-595 not yet reported which blocks → SOUTHWESTERN BELL 9533 ATLAS TX
— 817-596 not yet reported which blocks → SOUTHWESTERN BELL 9533 WEATHERFD TX
— 817-597 not yet reported which blocks → SOUTHWESTERN BELL 9533 WEATHERFD TX
— 817-598 not yet reported which blocks → SOUTHWESTERN BELL 9533 WEATHERFD TX
— 817-599 not yet reported which blocks → SOUTHWESTERN BELL 9533 WEATHERFD TX
— 817-601 1XXX2XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 GRAPEVINE TX
— 817-602 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - TX 6506 ARLINGTON TX
— 817-604 not yet reported which blocks → SPOK, INC. 6630 GRAPEVINE TX
— 817-605 not yet reported which blocks → SOUTHWESTERN BELL 9533 NRICHLDHLS TX
— 817-606 7XXX8XXX9XXX · 3 holders which blocks → SOUTHWESTERN BELL 9533 ARLINGTON TX
— 817-607 3XXX8XXX which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-608 1XXX6XXX7XXX · 3 holders which blocks → SOUTHWESTERN BELL 9533 ARLINGTON TX
— 817-609 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 WEATHERFD TX
— 817-610 not yet reported which blocks → SOUTHWESTERN BELL 9533 XXXXXXXXXX TX
— 817-611 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX TX
— 817-612 0XXX1XXX2XXX3XXX4XXX5XXX7XXX8XXX9XXX · 3 holders which blocks → ONVOY, LLC - TX 903C AZLE TX
— 817-613 not yet reported which blocks → SOUTHWESTERN BELL 9533 WEATHERFD TX
— 817-614 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 GLENDALE TX
— 817-615 0XXX1XXX6XXX7XXX9XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-616 3XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → ONVOY, LLC - TX 903C ATLAS TX
— 817-618 0–9 XXXall 10 · 2 holders which blocks → BANDWIDTH.COM CLEC, LLC - TX 004F KENNEDALE TX
— 817-619 not yet reported which blocks → SOUTHWESTERN BELL 9533 ARLINGTON TX
— 817-621 not yet reported which blocks → SPOK, INC. 6630 ARLINGTON TX
— 817-623 4XXX5XXX7XXX9XXX · 3 holders which blocks → ONVOY, LLC - TX 903C KELLER TX
— 817-624 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH 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.