T-MOBILE US, INC.
ent_019e4688de483c51ff92253a7e944671
Disclosures
7
State AG · SEC 8-K · 3 jurisdictions
Multi-filing incidents
1
incidents joining 2+ filings here
Max affected reported
37,000,000
nationwide · SEC 8-K FEDERAL
Leak-site claims
0
none in sample
Identity resolution
- Canonical name
- T-MOBILE US, INC.
- Normalized
- t mobile us— dedupe via name-norm; Microsoft / MSFT collapse to one row
- GLEIF LEI
- 549300QHIJYOHPACPG31
- SEC EDGAR CIK
- 0001283699
- Domain
- None on record
- Corporate parent
- DEUTSCHE TELEKOM AG— per GLEIF relationship records
Disclosure history (7)newest first
- Indiana State AGas victim2025-08-29
T-Mobile reported a data breach to the Indiana Attorney General. The breach occurred on 2025-06-10 and was reported on 2025-08-29. 1 Indiana residents were affected. 2 individuals affected in total.
- New Hampshire State AGas victim2023-04-28
T-Mobile US, Inc. notified the New Hampshire Attorney General that a bad actor gained unauthorized access to limited information from a small number of T-Mobile accounts between late February and March 2023. One New Hampshire resident was affected. The compromised data included account PINs. T-Mobile reset the PINs, shut down access, and provided two years of free credit monitoring.
- FEDERALSEC 8-Kas victim2023-01-19
T-Mobile US, Inc. disclosed that a bad actor obtained data through an unauthorized API access starting around November 25, 2022. The company identified the activity on January 5, 2023, and contained it within a day. Approximately 37 million customer accounts were affected, exposing basic identity information such as name, address, email, phone number, and date of birth. Sensitive data like SSNs and payment card information was not accessed.
- New Hampshire State AGas victim2020-12-08
T-Mobile US, Inc. reported a security breach affecting seven New Hampshire residents. Between August 27 and September 6, 2020, an unknown actor accessed customer account information, including names, phone numbers, account numbers, PINs, and line counts. T-Mobile detected and terminated the unauthorized access, which appeared to involve porting lines to another carrier. Affected individuals received notification on November 25, 2020, and were offered two years of credit monitoring.
- New Hampshire State AGas victim2020-10-13
T-Mobile US, Inc. notified the NH AG of a breach affecting 1 NH resident. Unauthorized access occurred Aug 31-Sep 1, 2020. Actor accessed account info (name, address, phone, account #, driver's license, PIN) and attempted unauthorized line porting. T-Mobile terminated access and offered 2 years credit monitoring.
- Indiana State AGas victim2020-10-09
T‐Mobile reported a data breach to the Indiana Attorney General. The breach occurred on 2020-08-31 and was reported on 2020-10-09. 2 Indiana residents were affected.
- Indiana State AGas victim2020-03-10
T‐Mobile USA Inc reported a data breach to the Indiana Attorney General. The breach occurred on 2019-11-26 and was reported on 2020-03-10. 7 Indiana residents were affected. 1,027 individuals affected in total.
Subsidiary disclosures (newest 10)filed by group companies
◈ These filings were made by or about subsidiaries of T-MOBILE US, INC. — not by T-MOBILE US, INC. itself. Corporate relationships are mapped from GLEIF relationship records and SEC Exhibit 21 filings.
- Maine State AGvia T-MOBILE USA, INC.2026-03-31
T-Mobile, USA reported an insider wrongdoing incident to the Maine Attorney General. An unauthorized individual accessed limited information on one Maine resident's account on January 12, 2026. The breach was discovered on March 5, 2026. Affected data included name, address, email, account number, phone numbers, PIN, driver's license, DOB, and SSN. T-Mobile reset the account PIN and offered 24 months of credit monitoring. Notification was sent on March 31, 2026.
- Maine State AGvia USCC Services, LLC2024-02-13
USCC Services, LLC, operating as UScellular, reported a data breach that occurred on January 28, 2024, and was discovered the following day. An external system breach (hacking) affected 100 individuals, including 8 Maine residents. The compromised information included names in combination with financial account or credit/debit card numbers and their associated security codes or PINs. Written notifications were sent to the affected individuals on February 16, 2024.
- Massachusetts State AGvia T-MOBILE USA, INC.2023-04-28
T-Mobile USA reported a data breach to the Massachusetts Office of Consumer Affairs and Business Regulation. The breach was reported on 2023-04-28. 17 Massachusetts residents were affected. The report records the breach type as electronic.
- Maine State AGvia T-MOBILE USA, INC.2023-04-28
T-Mobile, USA experienced a security breach between February 24, 2023, and March 30, 2023, which was discovered on March 27, 2023. The breach, described as an external system hack, affected 836 individuals. The compromised information included names in combination with driver's license or non-driver identification card numbers. T-Mobile notified the affected individuals on April 28, 2023, and offered 24 months of complimentary credit monitoring and identity theft protection services through Transunion.
- Indiana State AGvia T-MOBILE USA, INC.2023-04-28
T‐Mobile reported a data breach to the Indiana Attorney General. The breach occurred on 2023-02-24 and was reported on 2023-04-28. 7 Indiana residents were affected. 836 individuals affected in total.
- Washington State AGvia T-MOBILE USA, INC.2023-01-19
T-Mobile USA reported unauthorized access to customer account information in Washington. The breach, discovered on Jan 5, 2023, affected names, contact details, and DOBs. Passwords and SSNs were not compromised. 772,593 Washington residents were notified.
- GLOBALLeak Sitevia T-MOBILE USA, INC.2022-04-21
- Massachusetts State AGvia T-MOBILE USA, INC.2022-03-08
T-Mobile reported a data breach to the Massachusetts Office of Consumer Affairs and Business Regulation. The breach was reported on 2022-03-08. 1 Massachusetts residents were affected. The report records the breach type as paper.
- New Hampshire State AGvia USCC Services, LLC2021-12-29
USCC Services, LLC (d/b/a UScellular) detected unauthorized access to its billing system on December 13, 2021, occurring between December 13-19, 2021. Unauthorized individuals accessed wireless customer accounts containing names, addresses, PINs, and phone numbers to fraudulently port numbers. Approximately 405 customers were affected nationwide, including 5 New Hampshire residents. UScellular disconnected affected systems, reset employee credentials, changed customer PINs, and reported the incident to law enforcement and the FCC.
- Maine State AGvia USCC Services, LLC2021-12-23
USCC Services, LLC d/b/a UScellular reported a phishing-based breach occurring between December 13 and 19, 2021. The incident affected 405 individuals, including 40 Maine residents. UScellular notified affected consumers in writing on December 27, 2021. No identity theft protection services were offered.