Singapore Telecommunications Limited (Singtel) seeks a potential stake sale in its Australian subsidiary Optus Mobile, on the same day Australia’s communications regulator commenced Federal Court proceedings against Optus Mobile, with a maximum penalty exposure of over A$250 million ($174 million).

In a statement on Thursday, Singtel said there is “no certainty or assurance” that any transaction will occur and that it will make an announcement if and when there are material developments that warrant disclosure.

Singtel seeks a like-minded Australian minority partner that aligns with its objective of ensuring Optus continues to operate as a strong alternative telecommunications provider in Australia, a position it first signaled in a statement on May 21, 2026.

Also on Thursday, in a statement, the Australian Communications and Media Authority (ACMA) alleges that during the September 18, 2025 outage, Optus Mobile breached two separate legal obligations on 1,005 occasions. The maximum penalty available to the court is A$250,000 per contravention.

Optus Mobile failed to give end-users access to the emergency call service and failed to ensure emergency calls were carried to the relevant termination point, the ACMA elaborated.

The proceedings follow earlier enforcement action arising from Optus’s November 2023 network outage. In this case, Singtel Optus subsidiaries including Optus Mobile paid more than A$12 million in infringement notice penalties imposed by the ACMA for breaches relating to emergency calls.

Nerida O’Loughlin, ACMA Chair, said the recurrence of a major network outage affecting emergency calls so soon after the November 2023 outage is a significant concern and one of the reasons the ACMA decided to take the matter to court.

Maybank sees Singtel as a long-term beneficiary of Physical AI in ASEAN