Ofcom fines Tismi £437,500 over 366,000 sub-allocated numbers

Ofcom fined Tismi BV £437,500 on October 21 for failing to stop scammers misusing its phone numbers. Tismi, part of Link Mobility, sub-allocates numbers to its own customers. Ofcom found it breached General Conditions B1.6, B1.8 and B1.9(c) between at least November 15, 2022 and January 1, 2025. It sub-allocated numbers without adequate due diligence, did not monitor for misuse, and had no documented process for handling misuse reports. About 366,000 sub-allocated numbers were exposed. The penalty is £625,000 less 30% for admitting liability and settling. Tismi must also show Ofcom evidence of its new due diligence, monitoring and incident response. The non-confidential decision will be published later.

The case opened on October 18, 2024. In June 2025 Ofcom directed Tismi under section 49 of the Communications Act to block calls and messages to and from specific mobile numbers linked to fraud, and Tismi complied. B1.6, B1.8 and B1.9(c) are the same three conditions Ofcom cited when it opened own-initiative cases against Voxbone and Vonage Business on September 24. On October 21 it also opened an investigation into Xtra Phones UK. “Any company that puts customers at the mercy of scammers will face the consequences,” said George Lusty, Ofcom’s Director of Enforcement.

The conduct ended in January 2025. The fine came 21 months later.