Simba admits unauthorised 2.3 GHz use as IMDA probe continues

Singapore's Simba Telecom has confirmed on its FY26 earnings call that it used spectrum outside the limits of its authorisations, an admission that sits at the centre of an ongoing investigation by regulator IMDA and has frozen the regulatory review of its acquisition of rival M1.

"Simba has been co-operating fully with the IMDA investigation. It appears that there has been intermittent use of some spectrum that Simba had previously been authorised to use, but only for specific purposes," the operator stated during the call.

IMDA suspended its review of the Simba-M1 deal in May, after learning that Simba "could have been using radio frequency bands that had not been assigned to them to provide mobile services." The regulator has since stated its position in plainer terms. "IMDA has indicated that it has evidence Simba used spectrum that it was not licensed to use," Simba itself acknowledges in its annual report, published alongside the FY26 results.

Such use would breach Singapore's Telecommunications Act 1999 and the conditions of Simba's facilities-based operations licence. The investigation remains open.

Which spectrum is in question?

Simba did not name the band on the call, but a report in The Straits Times identified the frequencies as 2.3 GHz — a 4G band. The specifics of Simba's licence portfolio explain why that band matters.

Simba holds 40 MHz of unpaired spectrum in the 2.3 GHz band, permitted only for 4G, plus 10 MHz unpaired in the 2.5 GHz band under the same 4G-only restriction. Its 5G licences cover 900 MHz and 2100 MHz — 2 x 10 MHz in each — along with 26 GHz and 28 GHz millimetre-wave holdings. The 900 MHz block is dual-purpose, cleared for both 4G and 5G.

Singapore does not apply technology neutrality when assigning frequencies. Operators may only use a band for the mobile technology generation explicitly assigned to it. In markets that do apply technology neutrality, operators can choose freely between 4G, 5G or both within their licensed spectrum — a flexibility Simba does not enjoy in Singapore.

That constraint is central to the operator's dilemma. Simba is wholly dependent on its 900 MHz and 2100 MHz holdings for its 5G Standalone strategy, and on the same earnings call it confirmed that the transition to a 5G SA network is progressing, with mobile core upgrades completed.

What did the company say about the cause?

Asked by an analyst whether the issue was "a software or hardware issue," company secretary Tony Moffatt gave a guarded reply.

"The situation was that there was some use of spectrum that was permitted by the IMDA and we then used it outside those limitations that were in that purpose," Moffatt said. "In terms of whether it was a software or a hardware type of issue, it's just a function of the way in which the system works. It's kind of a combination of both of those things. And that's really all we can say about that at this stage."

What are the possible consequences?

In the "principal business risk" section of its annual report, Simba laid out the range of outcomes IMDA's investigation could produce. The regulator has not advised what the consequences of a guilty finding would be.

"However, such consequences may include financial penalties, modification to, or termination of Simba's licences to operate in Singapore, and personal consequences for individuals found to have been involved," the company stated.

The stakes extend beyond penalties. Until IMDA reaches its findings, the suspended review of Simba's acquisition of M1 stays on hold, leaving the shape of Singapore's mobile market in limbo while one of its four operators awaits judgment.