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 773
ILLINOIS BELL TEL CO 257
T-MOBILE USA, INC. 169
NEW CINGULAR WIRELESS PCS, LLC - IL 84
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 59
MCIMETRO ACCESS TRANSMISSION SERVICES LLC 38
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
2007-05-22 773-946 0–9 XXXall 10 · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - IL 6115 CHICGOZN10 IL
2007-03-15 773-642 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
2007-03-15 773-803 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
2007-03-15 773-984 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
2007-03-05 773-657 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
2007-02-21 773-939 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 CHICGOZN08 IL
2007-02-20 773-571 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 CHICGOZN07 IL
2007-02-20 773-849 0–9 XXXall 10 · 2 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 CHICGOZN03 IL
2007-01-15 773-558 0–9 XXXall 10 · 2 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 CHICGOZN03 IL
2007-01-08 773-587 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
2007-01-08 773-930 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
2006-11-08 773-614 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 CHICGOZN10 IL
2006-11-08 773-629 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 CHICGOZN10 IL
2006-10-30 773-595 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 CHICGOZN07 IL
2006-10-24 773-754 0–9 XXXall 10 · 5 holders which blocks → COMCAST IP PHONE, LLC 318J CHICGOZN02 IL
2006-10-18 773-891 0–9 XXXall 10 · 2 holders which blocks → COMCAST IP PHONE, LLC 318J CHICGOZN07 IL
2006-10-16 773-951 0–9 XXXall 10 · 2 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 CHICGOZN03 IL
2006-10-03 773-853 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
2006-07-26 773-679 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 CHICGOZN10 IL
2006-07-21 773-877 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
2006-06-23 773-840 0–9 XXXall 10 · 4 holders which blocks → PAETEC ITEL, LLC 829J CHICGOZN10 IL
2006-06-08 773-979 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 CHICGOZN10 IL
2006-05-19 773-801 0–9 XXXall 10 · 4 holders which blocks → ILLINOIS BELL TEL CO 9329 CHICGOZN06 IL
2006-04-27 773-668 0–9 XXXall 10 · 2 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - IL 6115 CHICGOZN05 IL
2006-04-27 773-966 0–9 XXXall 10 · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - IL 6115 CHICGOZN07 IL
2006-04-05 773-605 0–9 XXXwhole prefix which blocks → FIRST COMMUNICATIONS, LLC 460K CHICGOZN02 IL
2006-03-21 773-574 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 CHICGOZN10 IL
2006-03-20 773-876 0–9 XXXall 10 · 2 holders which blocks → METROPCS, INC. 5562 CHICGOZN03 IL
2006-03-20 773-990 0–9 XXXall 10 · 2 holders which blocks → ILLINOIS BELL TEL CO 9329 CHICGOZN03 IL
2006-03-15 773-225 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
2006-03-15 773-899 0–9 XXXall 10 · 2 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 CHICGOZN03 IL
2005-10-19 773-563 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 CHICGOZN10 IL
2005-10-17 773-682 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 CHICGOZN03 IL
2005-10-17 773-724 0–9 XXXall 10 · 5 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 CHICGOZN03 IL
2005-10-10 773-621 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
2005-09-30 773-701 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 CHICGOZN10 IL
2005-09-30 773-954 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 CHICGOZN10 IL
2005-09-13 773-641 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
2005-07-18 773-706 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 CHICGOZN03 IL
2005-07-14 773-606 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
2005-06-30 773-603 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 CHICGOZN10 IL
2005-06-30 773-656 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 CHICGOZN10 IL
2005-04-22 773-567 0–9 XXXall 10 · 2 holders which blocks → METROPCS, INC. 5562 CHICGOZN03 IL
2005-04-19 773-699 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
2005-03-28 773-816 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 CHICGOZN10 IL
2005-03-28 773-987 0–9 XXXall 10 · 2 holders which blocks → FIRST COMMUNICATIONS, LLC 460K CHICGOZN10 IL
2005-03-08 773-885 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
2005-02-21 773-678 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL
2005-01-21 773-597 0–9 XXXall 10 · 7 holders which blocks → FIRST COMMUNICATIONS, LLC 460K CHICGOZN07 IL
2005-01-10 773-559 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 CHICGOZN03 IL

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.