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 956
SOUTHWESTERN BELL 145
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
— 956-421 not yet reported which blocks → SOUTHWESTERN BELL 9533 HARLINGEN TX
— 956-423 not yet reported which blocks → SOUTHWESTERN BELL 9533 HARLINGEN TX
— 956-424 2XXX4XXX5XXX6XXX8XXX · 4 holders which blocks → SOUTHWESTERN BELL 9533 MISSION TX
— 956-425 not yet reported which blocks → SOUTHWESTERN BELL 9533 HARLINGEN TX
— 956-427 not yet reported which blocks → SOUTHWESTERN BELL 9533 HARLINGEN TX
— 956-428 not yet reported which blocks → SOUTHWESTERN BELL 9533 HARLINGEN TX
— 956-429 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → SOUTHWESTERN BELL 9533 MCALLEN TX
— 956-430 not yet reported which blocks → SOUTHWESTERN BELL 9533 HARLINGEN TX
— 956-440 5XXX which blocks → SOUTHWESTERN BELL 9533 HARLINGEN TX
— 956-444 2XXX4XXX6XXX8XXX9XXX · 4 holders which blocks → SOUTHWESTERN BELL 9533 HARLINGEN TX
— 956-461 0XXX1XXX7XXX8XXX9XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 DONNA TX
— 956-464 not yet reported which blocks → SOUTHWESTERN BELL 9533 DONNA TX
— 956-473 8XXX9XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 LAREDO TX
— 956-485 0XXX3XXX4XXX5XXX6XXX7XXX8XXX · 7 holders which blocks → SOUTHWESTERN BELL 9533 SULLIVANCY TX
— 956-504 not yet reported which blocks → SOUTHWESTERN BELL 9533 BROWNSVL TX
— 956-514 not yet reported which blocks → SOUTHWESTERN BELL 9533 MERCEDES TX
— 956-519 not yet reported which blocks → SOUTHWESTERN BELL 9533 MISSION TX
— 956-541 not yet reported which blocks → SOUTHWESTERN BELL 9533 BROWNSVL TX
— 956-542 not yet reported which blocks → SOUTHWESTERN BELL 9533 BROWNSVL TX
— 956-544 not yet reported which blocks → SOUTHWESTERN BELL 9533 BROWNSVL TX
— 956-546 not yet reported which blocks → SOUTHWESTERN BELL 9533 BROWNSVL TX
— 956-547 0XXX which blocks → SOUTHWESTERN BELL 9533 BROWNSVL TX
— 956-548 not yet reported which blocks → SOUTHWESTERN BELL 9533 BROWNSVL TX
— 956-550 5XXX which blocks → SOUTHWESTERN BELL 9533 BROWNSVL TX
— 956-554 1XXX8XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 BROWNSVL TX
— 956-565 not yet reported which blocks → SOUTHWESTERN BELL 9533 MERCEDES TX
— 956-574 1XXX2XXX4XXX which blocks → SOUTHWESTERN BELL 9533 BROWNSVL TX
— 956-580 not yet reported which blocks → SOUTHWESTERN BELL 9533 MISSION TX
— 956-581 not yet reported which blocks → SOUTHWESTERN BELL 9533 MISSION TX
— 956-583 8XXX which blocks → SOUTHWESTERN BELL 9533 MISSION TX
— 956-584 not yet reported which blocks → SOUTHWESTERN BELL 9533 MISSION TX
— 956-585 not yet reported which blocks → SOUTHWESTERN BELL 9533 MISSION TX
— 956-618 not yet reported which blocks → SOUTHWESTERN BELL 9533 MCALLEN TX
— 956-630 not yet reported which blocks → SOUTHWESTERN BELL 9533 MCALLEN TX
— 956-631 not yet reported which blocks → SOUTHWESTERN BELL 9533 MCALLEN TX
— 956-632 not yet reported which blocks → SOUTHWESTERN BELL 9533 MCALLEN TX
— 956-661 8XXX which blocks → SOUTHWESTERN BELL 9533 MCALLEN TX
— 956-664 not yet reported which blocks → SOUTHWESTERN BELL 9533 MCALLEN TX
— 956-668 not yet reported which blocks → SOUTHWESTERN BELL 9533 MCALLEN TX
— 956-682 not yet reported which blocks → SOUTHWESTERN BELL 9533 MCALLEN TX
— 956-683 5XXX6XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 MCALLEN TX
— 956-686 not yet reported which blocks → SOUTHWESTERN BELL 9533 MCALLEN TX
— 956-687 not yet reported which blocks → SOUTHWESTERN BELL 9533 MCALLEN TX
— 956-688 0XXX7XXX8XXX9XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 MCALLEN TX
— 956-702 not yet reported which blocks → SOUTHWESTERN BELL 9533 PHARR TX
— 956-712 not yet reported which blocks → SOUTHWESTERN BELL 9533 LAREDO TX
— 956-717 not yet reported which blocks → SOUTHWESTERN BELL 9533 LAREDO TX
— 956-718 not yet reported which blocks → SOUTHWESTERN BELL 9533 LAREDO TX
— 956-721 6XXX which blocks → SOUTHWESTERN BELL 9533 LAREDO TX
— 956-722 not yet reported which blocks → SOUTHWESTERN BELL 9533 LAREDO 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.