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 501
SOUTHWESTERN BELL 165
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
2007-03-08 501-251 0–9 XXXall 10 · 5 holders which blocks → SOUTHWESTERN BELL 9533 LITTLEROCK AR
2001-05-08 501-365 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 7 holders which blocks → SOUTHWESTERN BELL 9533 HEBER SPG AR
2001-05-08 501-566 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 7 holders which blocks → SOUTHWESTERN BELL 9533 JONESMILLS AR
2001-01-18 501-548 1XXX2XXX4XXX5XXX7XXX8XXX9XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 CONWAY AR
— 501-202 not yet reported which blocks → SOUTHWESTERN BELL 9533 LITTLEROCK AR
— 501-206 1XXX2XXX4XXX which blocks → SOUTHWESTERN BELL 9533 HEBER SPG AR
— 501-207 0XXX8XXX9XXX · 3 holders which blocks → SOUTHWESTERN BELL 9533 SEARCY AR
— 501-208 0XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → SOUTHWESTERN BELL 9533 MORRILTON AR
— 501-210 5XXX8XXX which blocks → SOUTHWESTERN BELL 9533 LITTLEROCK AR
— 501-212 not yet reported which blocks → SOUTHWESTERN BELL 9533 LITTLEROCK AR
— 501-217 not yet reported which blocks → SOUTHWESTERN BELL 9533 LITTLEROCK AR
— 501-218 3XXX4XXX5XXX6XXX8XXX9XXX · 3 holders which blocks → SOUTHWESTERN BELL 9533 LITTLEROCK AR
— 501-219 not yet reported which blocks → SOUTHWESTERN BELL 9533 LITTLEROCK AR
— 501-221 not yet reported which blocks → SOUTHWESTERN BELL 9533 LITTLEROCK AR
— 501-223 7XXX which blocks → SOUTHWESTERN BELL 9533 LITTLEROCK AR
— 501-224 not yet reported which blocks → SOUTHWESTERN BELL 9533 LITTLEROCK AR
— 501-225 not yet reported which blocks → SOUTHWESTERN BELL 9533 LITTLEROCK AR
— 501-227 2XXX which blocks → SOUTHWESTERN BELL 9533 LITTLEROCK AR
— 501-228 not yet reported which blocks → SOUTHWESTERN BELL 9533 LITTLEROCK AR
— 501-244 3XXX8XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 LITTLEROCK AR
— 501-250 1XXX2XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 HEBER SPG AR
— 501-257 0XXX7XXX which blocks → SOUTHWESTERN BELL 9533 LITTLEROCK AR
— 501-261 0XXX2XXX3XXX4XXX5XXX6XXX8XXX9XXX · 6 holders which blocks → SOUTHWESTERN BELL 9533 SPRINGLAKE AR
— 501-262 7XXX8XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 HOTSPRINGS AR
— 501-265 9XXX which blocks → SOUTHWESTERN BELL 9533 LITTLEROCK AR
— 501-268 not yet reported which blocks → SOUTHWESTERN BELL 9533 SEARCY AR
— 501-278 4XXX which blocks → SOUTHWESTERN BELL 9533 SEARCY AR
— 501-279 not yet reported which blocks → SOUTHWESTERN BELL 9533 SEARCY AR
— 501-280 not yet reported which blocks → SOUTHWESTERN BELL 9533 LITTLEROCK AR
— 501-281 not yet reported which blocks → SOUTHWESTERN BELL 9533 SEARCY AR
— 501-296 not yet reported which blocks → SOUTHWESTERN BELL 9533 LITTLEROCK AR
— 501-301 0XXX4XXX which blocks → SOUTHWESTERN BELL 9533 LITTLEROCK AR
— 501-303 0XXX4XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → SOUTHWESTERN BELL 9533 BENTON AR
— 501-305 0XXX1XXX2XXX9XXX · 3 holders which blocks → SOUTHWESTERN BELL 9533 SEARCY AR
— 501-312 not yet reported which blocks → SOUTHWESTERN BELL 9533 LITTLEROCK AR
— 501-315 6XXX8XXX which blocks → SOUTHWESTERN BELL 9533 BENTON AR
— 501-316 3XXX4XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → SOUTHWESTERN BELL 9533 BENTON AR
— 501-317 0XXX1XXX which blocks → SOUTHWESTERN BELL 9533 BENTON AR
— 501-318 3XXX4XXX which blocks → SOUTHWESTERN BELL 9533 HOTSPRINGS AR
— 501-319 2XXX3XXX4XXX5XXX6XXX7XXX · 3 holders which blocks → SOUTHWESTERN BELL 9533 LITTLEROCK AR
— 501-321 not yet reported which blocks → SOUTHWESTERN BELL 9533 HOTSPRINGS AR
— 501-324 not yet reported which blocks → SOUTHWESTERN BELL 9533 LITTLEROCK AR
— 501-327 not yet reported which blocks → SOUTHWESTERN BELL 9533 CONWAY AR
— 501-328 0XXX which blocks → SOUTHWESTERN BELL 9533 CONWAY AR
— 501-329 not yet reported which blocks → SOUTHWESTERN BELL 9533 CONWAY AR
— 501-332 not yet reported which blocks → SOUTHWESTERN BELL 9533 MALVERN AR
— 501-336 not yet reported which blocks → SOUTHWESTERN BELL 9533 CONWAY AR
— 501-337 none assigned yet which blocks → SOUTHWESTERN BELL 9533 MALVERN AR
— 501-340 0XXX which blocks → SOUTHWESTERN BELL 9533 LITTLEROCK AR
— 501-342 not yet reported which blocks → SOUTHWESTERN BELL 9533 CONWAY AR

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.