NumberResearch Membership · Data 09/21/2026

Recent prefix assignments

0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/21/2026

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
SOUTHWESTERN BELL TELEPHONE COMPANY - TX 3
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
— 817-801 not yet reported which blocks → SOUTHWESTERN BELL 9533 ARLINGTON TX
— 817-804 not yet reported which blocks → SOUTHWESTERN BELL 9533 ARLINGTON TX
— 817-810 6XXX8XXX which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-816 not yet reported which blocks → SOUTHWESTERN BELL 9533 ARLINGTON TX
— 817-820 9XXX which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-831 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-834 9XXX which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-835 1XXX3XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 EULESS TX
— 817-837 0XXX5XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 ROANOKE TX
— 817-838 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-841 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-847 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-849 0XXX2XXX4XXX5XXX6XXX7XXX9XXX · 4 holders which blocks → SOUTHWESTERN BELL 9533 NRICHLDHLS TX
— 817-850 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-852 5XXX6XXX9XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-854 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → SOUTHWESTERN BELL 9533 ROANOKE TX
— 817-856 0XXX2XXX7XXX8XXX9XXX · 4 holders which blocks → SOUTHWESTERN BELL 9533 ARLINGTON TX
— 817-858 not yet reported which blocks → SOUTHWESTERN BELL 9533 EULESS TX
— 817-860 8XXX which blocks → SOUTHWESTERN BELL 9533 ARLINGTON TX
— 817-861 not yet reported which blocks → SOUTHWESTERN BELL 9533 ARLINGTON TX
— 817-862 0XXX1XXX3XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-867 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-868 not yet reported which blocks → SOUTHWESTERN BELL 9533 EULESS TX
— 817-870 6XXX which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-871 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-877 6XXX7XXX which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-878 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-882 6XXX which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-884 6XXX7XXX which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-885 0XXX4XXX5XXX9XXX · 3 holders which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-890 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 ROANOKE TX
— 817-892 not yet reported which blocks → SOUTHWESTERN BELL 9533 ARLINGTON TX
— 817-912 1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → SOUTHWESTERN BELL TELEPHONE COMPANY - TX 7726 GRAPEVINE TX
— 817-920 2XXX3XXX4XXX8XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-921 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-922 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-923 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-924 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-926 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-927 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-930 not yet reported which blocks → SOUTHWESTERN BELL 9533 GLENDALE TX
— 817-931 not yet reported which blocks → SOUTHWESTERN BELL 9533 EULESS TX
— 817-935 0XXX8XXX9XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-950 not yet reported which blocks → SOUTHWESTERN BELL 9533 XXXXXXXXXX TX
— 817-952 1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → SOUTHWESTERN BELL 9533 EULESS TX
— 817-955 not yet reported which blocks → SOUTHWESTERN BELL 9533 XXXXXXXXXX TX
— 817-956 not yet reported which blocks → SOUTHWESTERN BELL 9533 EULESS TX
— 817-961 1XXX2XXX3XXX4XXX8XXX9XXX · 3 holders which blocks → SOUTHWESTERN BELL 9533 ROANOKE TX
— 817-962 0XXX2XXX3XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → SOUTHWESTERN BELL 9533 ARLINGTON TX
— 817-963 not yet reported which blocks → SOUTHWESTERN BELL 9533 EULESS TX

Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/21/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.