NumberResearch Membership · Data 09/19/2026

Recent prefix assignments

0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/19/2026

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 571
COMCAST IP PHONE, LLC 19
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
2012-11-19 571-395 0–9 XXXall 10 · 3 holders which blocks → COMCAST IP PHONE, LLC 318J WSNGTNZN17 VA
2011-04-12 571-492 0–9 XXXall 10 · 7 holders which blocks → COMCAST IP PHONE, LLC 318J OCCOQUAN VA
2011-04-12 571-542 0–9 XXXwhole prefix which blocks → COMCAST IP PHONE, LLC 318J DALE CITY VA
2010-09-23 571-358 0–9 XXXall 10 · 5 holders which blocks → COMCAST IP PHONE, LLC 318J MANASSAS VA
2010-06-10 571-659 0–9 XXXall 10 · 5 holders which blocks → COMCAST IP PHONE, LLC 318J DALE CITY VA
2010-06-07 571-319 0–9 XXXall 10 · 4 holders which blocks → COMCAST IP PHONE, LLC 318J WSNGTNZN08 VA
2008-02-01 571-308 0–9 XXXall 10 · 5 holders which blocks → COMCAST IP PHONE, LLC 318J WSNGTNZN19 VA
2007-07-03 571-257 0–9 XXXall 10 · 2 holders which blocks → COMCAST IP PHONE, LLC 318J WSNGTNZN08 VA
2007-04-17 571-208 0–9 XXXall 10 · 5 holders which blocks → COMCAST IP PHONE, LLC 318J MANASSAS VA
2006-10-23 571-312 0–9 XXXall 10 · 2 holders which blocks → COMCAST IP PHONE, LLC 318J WSNGTNZN08 VA
2006-10-23 571-830 0–9 XXXall 10 · 6 holders which blocks → COMCAST IP PHONE, LLC 318J WSNGTNZN17 VA
2006-10-20 571-918 0–9 XXXall 10 · 5 holders which blocks → COMCAST IP PHONE, LLC 318J LEESBURG VA
2006-09-18 571-313 0–9 XXXall 10 · 7 holders which blocks → COMCAST IP PHONE, LLC 318J HERNDON VA
2006-01-26 571-379 0–9 XXXall 10 · 2 holders which blocks → COMCAST IP PHONE, LLC 318J MANASSAS VA
2006-01-26 571-970 0–9 XXXall 10 · 3 holders which blocks → COMCAST IP PHONE, LLC 318J WSNGTNZN08 VA
2005-01-03 571-527 0–9 XXXall 10 · 3 holders which blocks → COMCAST IP PHONE, LLC 318J WSNGTNZN08 VA
— 571-206 0–9 XXXall 10 · 5 holders which blocks → COMCAST IP PHONE, LLC 318J LEESBURG VA
— 571-333 not yet reported which blocks → COMCAST IP PHONE, LLC 318J LEESBURG VA
— 571-407 0–9 XXXall 10 · 5 holders which blocks → COMCAST IP PHONE, LLC 318J WSNGTNZN19 VA

Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/19/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.