Tuas (ASX:TUA) shares closed 30.5% lower at A$1.27 on Monday 26 October 2026, after Singapore’s telecoms regulator issued a show cause notice to its mobile business, Simba Telecom. The shares fell as much as about 40% during the day, according to Reuters, and hit a 52-week low.
What the regulator alleges
According to Tuas’s ASX announcement, Singapore’s Infocomm Media Development Authority (IMDA) issued the notice on 23 October, asking Simba to explain why IMDA should not make findings against it. The six matters include:
- Spectrum sharing: using a 2100 MHz band for 4G as well as 5G at about 133 sites in 2022 and 2023, when it was only authorised for 5G
- Unauthorised spectrum: using the 2340 to 2360 MHz band at about 92 sites at times between 2023 and 2026 without authorisation
- Intent: IMDA alleges both were deliberate and approved by Simba’s senior management
- Early 5G Indoor rollout at two locations before approval
- A production order that IMDA says Simba did not fully comply with
- Concerns about Simba’s governance and compliance culture
IMDA has not reached any conclusion yet, and Simba must respond by 16 November 2026.
What penalties Simba could face
Possible actions include:
- Fines of up to the higher of 10% of annual turnover for the relevant business or S$1 million
- Suspension or cancellation of its spectrum rights or licence, in whole or part
- Compliance orders and new licence conditions
Tuas said it “does not intend to provide further comment” on the matters.
This is not the first warning
In May 2026, IMDA suspended its review of Simba’s planned acquisition of Singapore rival M1 after finding Simba may have used radio frequencies it had not been assigned, according to Must Share News. M1 owner Keppel let the deal lapse on 21 May.
Tuas shares are down about 73% over the past year, according to the Motley Fool.
The insider angle
Founder and chairman David Teoh is Tuas’s largest shareholder, with 172,986,163 shares or about 32.2%, according to his latest substantial holder notice. Monday’s fall cut the value of that stake by roughly A$96 million, to about A$220 million.
Washington H. Soul Pattinson holds about 14.6%.
Directors who bought last year are also deep in the red. Sarah Kenny bought at A$6.74 and Craig Levy at A$5.51 in October 2025, according to Market Index records, and both are now down about 77% to 81%. Our Megaport insider trading analysis explains how to read director trades.
What Tuas investors should watch
- Simba’s response to IMDA, due 16 November
- IMDA’s decision on fines or licence action
- Director trades in Appendix 3Y notices after the crash
- The AGM, where shareholders may question the board
Bottom line
Tuas now faces serious regulatory risk to Simba, its core business. Until IMDA rules, the shares are likely to stay volatile. As with Zip’s record crash, investors will be watching whether insiders step in.
