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 510
T-MOBILE USA, INC. 65
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
2024-05-31 510-810 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 OKLD ALMD CA
2021-03-04 510-916 0XXX1XXX2XXX3XXX4XXX5XXX6XXX8XXX9XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 OKLD TRNID CA
2021-02-25 510-973 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 OKLD BKLY CA
2019-11-08 510-767 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 FRNK MAIN CA
2019-10-16 510-630 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 ELSBR-PINL CA
2019-09-27 510-216 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 OKLD FRTVL CA
2019-05-28 510-807 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 HAYWARD CA
2019-03-21 510-988 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 OKLD FRTVL CA
2018-04-11 510-609 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 RICHMOND CA
2016-10-21 510-822 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 OKLD TRNID CA
2016-09-26 510-570 0–9 XXXall 10 · 7 holders which blocks → T-MOBILE USA, INC. 6529 OKLD BKLY CA
2016-08-30 510-513 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 FRNK MAIN CA
2016-07-29 510-424 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 OKLD FRTVL CA
2016-06-14 510-890 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 RICHMOND CA
2016-06-10 510-993 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 OKLD BKLY CA
2016-04-01 510-707 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 OKLD TRNID CA
2016-01-15 510-345 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 OKLD BKLY CA
2015-09-25 510-422 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 OKLD FRTVL CA
2015-09-22 510-203 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 FRNK MAIN CA
2015-09-22 510-241 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 ELSBR-PINL CA
2015-09-09 510-756 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 OKLD TRNID CA
2015-07-10 510-820 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 OKLD TRNID CA
2015-06-22 510-696 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 OKLD FRTVL CA
2015-05-01 510-640 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 ELSBR-PINL CA
2015-04-13 510-850 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 OKLD TRNID CA
2015-03-11 510-934 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 OKLD FRTVL CA
2014-11-25 510-753 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 OKLD TRNID CA
2014-10-24 510-309 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 ELSBR-PINL CA
2014-10-03 510-944 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 OKLD BKLY CA
2013-12-09 510-736 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 HAYWARD CA
2013-09-26 510-365 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 OKLD BKLY CA
2013-09-26 510-480 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 ELSBR-PINL CA
2013-05-16 510-362 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 HAYWARD CA
2013-01-31 510-328 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 OKLD FRTVL CA
2013-01-18 510-598 0–9 XXXall 10 · 7 holders which blocks → T-MOBILE USA, INC. 6529 FRNK MAIN CA
2007-07-02 510-314 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 HAYWARD CA
2007-02-15 510-230 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 RICHMOND CA
2002-09-19 510-213 4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → T-MOBILE USA, INC. 6529 OKLD FRTVL CA
2002-09-19 510-417 1XXX2XXX3XXX4XXX6XXX7XXX8XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 ELSBR-PINL CA
2002-09-19 510-717 7XXX which blocks → T-MOBILE USA, INC. 6529 OKLD BKLY CA
2001-12-26 510-282 not yet reported which blocks → T-MOBILE USA, INC. 6529 OKLD MN-PD CA
2001-12-26 510-375 6XXX which blocks → T-MOBILE USA, INC. 6529 RICHMOND CA
2001-12-26 510-396 not yet reported which blocks → T-MOBILE USA, INC. 6529 FRNK MAIN CA
2001-10-18 510-224 2XXX3XXX4XXX5XXX9XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 HRCUL-RODE CA
2001-09-19 510-415 not yet reported which blocks → T-MOBILE USA, INC. 6529 HAYWARD CA
2001-09-19 510-691 0XXX2XXX4XXX5XXX6XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 HRCUL-RODE CA
2001-05-17 510-557 2XXX3XXX4XXX5XXX8XXX9XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 FRNK MAIN CA
2001-04-20 510-455 2XXX3XXX4XXX5XXX7XXX8XXX9XXX · 4 holders which blocks → T-MOBILE USA, INC. 6529 CROCKETT CA
2001-03-22 510-932 none assigned yet which blocks → T-MOBILE USA, INC. 6529 RICHMOND CA
— 510-290 none assigned yet which blocks → T-MOBILE USA, INC. 6529 OKLD MN-PD CA

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.