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 573
SOUTHWESTERN BELL 128
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
— 573-744 0XXX2XXX3XXX4XXX6XXX7XXX8XXX · 4 holders which blocks → SOUTHWESTERN BELL 9533 FREEBURG MO
— 573-747 4XXX5XXX9XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 FARMINGTON MO
— 573-748 3XXX4XXX6XXX8XXX9XXX · 5 holders which blocks → SOUTHWESTERN BELL 9533 NEW MADRID MO
— 573-754 7XXX9XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 LOUISIANA MO
— 573-756 not yet reported which blocks → SOUTHWESTERN BELL 9533 FARMINGTON MO
— 573-757 0XXX3XXX4XXX · 3 holders which blocks → SOUTHWESTERN BELL 9533 DEERING MO
— 573-760 none assigned yet which blocks → SOUTHWESTERN BELL 9533 FARMINGTON MO
— 573-776 none assigned yet which blocks → SOUTHWESTERN BELL 9533 POPLAR BLF MO
— 573-778 none assigned yet which blocks → SOUTHWESTERN BELL 9533 POPLAR BLF MO
— 573-784 0XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → SOUTHWESTERN BELL 9533 FRANKFORD MO
— 573-785 not yet reported which blocks → SOUTHWESTERN BELL 9533 POPLAR BLF MO
— 573-788 0XXX3XXX4XXX5XXX6XXX8XXX · 4 holders which blocks → SOUTHWESTERN BELL 9533 OLDAPPLETN MO
— 573-792 0XXX2XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 HOLCOMB MO
— 573-794 3XXX4XXX5XXX · 3 holders which blocks → SOUTHWESTERN BELL 9533 DELTA MO
— 573-824 0XXX2XXX3XXX4XXX7XXX8XXX9XXX · 6 holders which blocks → SOUTHWESTERN BELL 9533 ALTEBGFRHN MO
— 573-833 0XXX3XXX4XXX5XXX8XXX9XXX · 4 holders which blocks → SOUTHWESTERN BELL 9533 POCAHONTAS MO
— 573-840 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 7 holders which blocks → SOUTHWESTERN BELL 9533 POPLAR BLF MO
— 573-847 0XXX3XXX4XXX5XXX8XXX · 4 holders which blocks → SOUTHWESTERN BELL 9533 PAYNESVL MO
— 573-866 0XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → SOUTHWESTERN BELL 9533 PATTON MO
— 573-873 0XXX2XXX4XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → SOUTHWESTERN BELL 9533 CAMDENTON MO
— 573-883 none assigned yet which blocks → SOUTHWESTERN BELL 9533 STEGNVIEVE MO
— 573-887 0XXX2XXX5XXX7XXX8XXX · 4 holders which blocks → SOUTHWESTERN BELL 9533 CHAFFEE MO
— 573-888 none assigned yet which blocks → SOUTHWESTERN BELL 9533 KENNETT MO
— 573-897 none assigned yet which blocks → SOUTHWESTERN BELL 9533 LINN MO
— 573-898 0XXX4XXX6XXX7XXX8XXX · 4 holders which blocks → SOUTHWESTERN BELL 9533 ELSBERRY MO
— 573-964 0XXX1XXX4XXX7XXX9XXX · 5 holders which blocks → SOUTHWESTERN BELL 9533 LKOZKOSBCH MO
— 573-967 0XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → SOUTHWESTERN BELL 9533 FISK MO
— 573-986 0XXX which blocks → SOUTHWESTERN BELL 9533 CAPEGIRARD MO

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.