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 563
QWEST CORPORATION 54
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
2004-04-29 563-272 0–9 XXXall 10 · 5 holders which blocks → QWEST CORPORATION 9631 MUSCATINE IA
— 563-241 2XXX3XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → QWEST CORPORATION 9631 CLINTON IA
— 563-242 not yet reported which blocks → QWEST CORPORATION 9631 CLINTON IA
— 563-243 not yet reported which blocks → QWEST CORPORATION 9631 CLINTON IA
— 563-244 not yet reported which blocks → QWEST CORPORATION 9631 CLINTON IA
— 563-259 5XXX6XXX7XXX · 3 holders which blocks → QWEST CORPORATION 9631 CLINTON IA
— 563-262 not yet reported which blocks → QWEST CORPORATION 9631 MUSCATINE IA
— 563-263 not yet reported which blocks → QWEST CORPORATION 9631 MUSCATINE IA
— 563-264 not yet reported which blocks → QWEST CORPORATION 9631 MUSCATINE IA
— 563-284 0XXX1XXX2XXX3XXX7XXX · 5 holders which blocks → QWEST CORPORATION 9631 WALCOTT IA
— 563-288 5XXX which blocks → QWEST CORPORATION 9631 MUSCATINE IA
— 563-322 not yet reported which blocks → QWEST CORPORATION 9631 DAVENPORT IA
— 563-323 not yet reported which blocks → QWEST CORPORATION 9631 DAVENPORT IA
— 563-324 not yet reported which blocks → QWEST CORPORATION 9631 DAVENPORT IA
— 563-326 not yet reported which blocks → QWEST CORPORATION 9631 DAVENPORT IA
— 563-327 not yet reported which blocks → QWEST CORPORATION 9631 DAVENPORT IA
— 563-328 not yet reported which blocks → QWEST CORPORATION 9631 DAVENPORT IA
— 563-332 not yet reported which blocks → QWEST CORPORATION 9631 DAVENPORT IA
— 563-333 not yet reported which blocks → QWEST CORPORATION 9631 DAVENPORT IA
— 563-336 not yet reported which blocks → QWEST CORPORATION 9631 DAVENPORT IA
— 563-344 not yet reported which blocks → QWEST CORPORATION 9631 DAVENPORT IA
— 563-355 not yet reported which blocks → QWEST CORPORATION 9631 DAVENPORT IA
— 563-359 not yet reported which blocks → QWEST CORPORATION 9631 DAVENPORT IA
— 563-381 0XXX7XXX · 2 holders which blocks → QWEST CORPORATION 9631 DAVENPORT IA
— 563-382 not yet reported which blocks → QWEST CORPORATION 9631 DECORAH IA
— 563-383 not yet reported which blocks → QWEST CORPORATION 9631 DAVENPORT IA
— 563-386 not yet reported which blocks → QWEST CORPORATION 9631 DAVENPORT IA
— 563-387 6XXX7XXX8XXX9XXX · 4 holders which blocks → QWEST CORPORATION 9631 DECORAH IA
— 563-388 not yet reported which blocks → QWEST CORPORATION 9631 DAVENPORT IA
— 563-391 not yet reported which blocks → QWEST CORPORATION 9631 DAVENPORT IA
— 563-421 none assigned yet which blocks → QWEST CORPORATION 9631 DAVENPORT IA
— 563-422 0XXX1XXX2XXX4XXX7XXX8XXX · 2 holders which blocks → QWEST CORPORATION 9631 WEST UNION IA
— 563-441 not yet reported which blocks → QWEST CORPORATION 9631 DAVENPORT IA
— 563-445 not yet reported which blocks → QWEST CORPORATION 9631 DAVENPORT IA
— 563-449 2XXX4XXX5XXX6XXX · 2 holders which blocks → QWEST CORPORATION 9631 DAVENPORT IA
— 563-459 7XXX8XXX9XXX · 2 holders which blocks → QWEST CORPORATION 9631 DAVENPORT IA
— 563-468 0XXX1XXX3XXX7XXX8XXX9XXX which blocks → QWEST CORPORATION 9631 DAVENPORT IA
— 563-538 0XXX1XXX2XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → QWEST CORPORATION 9631 LANSING IA
— 563-552 0XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → QWEST CORPORATION 9631 DUBUQUE IA
— 563-556 not yet reported which blocks → QWEST CORPORATION 9631 DUBUQUE IA
— 563-557 not yet reported which blocks → QWEST CORPORATION 9631 DUBUQUE IA
— 563-562 0XXX1XXX2XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → QWEST CORPORATION 9631 CALMAR IA
— 563-568 1XXX7XXX8XXX9XXX · 2 holders which blocks → QWEST CORPORATION 9631 WAUKON IA
— 563-582 not yet reported which blocks → QWEST CORPORATION 9631 DUBUQUE IA
— 563-583 not yet reported which blocks → QWEST CORPORATION 9631 DUBUQUE IA
— 563-584 not yet reported which blocks → QWEST CORPORATION 9631 DUBUQUE IA
— 563-585 not yet reported which blocks → QWEST CORPORATION 9631 DUBUQUE IA
— 563-587 8XXX9XXX · 2 holders which blocks → QWEST CORPORATION 9631 DUBUQUE IA
— 563-588 not yet reported which blocks → QWEST CORPORATION 9631 DUBUQUE IA
— 563-589 not yet reported which blocks → QWEST CORPORATION 9631 DUBUQUE IA

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.