StarHub and M1 are in merger talks that would shrink Singapore's mobile market from four operators to three, matching the minimum structure most regulators consider viable for competition.

The negotiations are part of a broader Asia-Pacific shift toward consolidation and network sharing. In the last four years, both Indonesia and Taiwan have moved from five mobile network operators to three, while Malaysia has gone from four to three.

How large would a combined StarHub-M1 be?

The merged entity would rival Singapore Telecommunications (Singtel) in mobile and broadband subscribers. Singtel held 43% of Singapore's mobile market in June, with M1 at 22%, StarHub at 21% and Simba at 14%.

StarHub cautioned that negotiations are still continuing. The two operators already share 5G spectrum and RAN infrastructure through Antina, a jointly-owned company established under the terms of their 5G licences.

What is the New Zealand proposal?

Across the Tasman, 2degrees and One New Zealand (OneNZ) have proposed combining their radio networks into a single jointly-owned entity, announced a month ago. The new company would manage the shared infrastructure commercially, mirroring Antina's role in Singapore.

"The merged RANs would allow for more efficient investment in expanding coverage and increasing capacity," 2degrees said. Commerce Commission clearance is expected next year.

2degrees is owned by Australia's Macquarie Asset Management and Aware Super. OneNZ is owned by New Zealand infrastructure investor Infratil.

Are network-sharing deals becoming the norm?

Network sharing has defined Asia-Pacific telecoms this decade. In Australia, Optus and TPG Telecom last year struck a spectrum and infrastructure partnership covering rural areas. TPG paid 1.6 billion Australian dollars (US$1.1 billion) for access to Optus mobile towers, while letting Optus use some of its 700MHz and 1800MHz spectrum.

The largest arrangement is the China Telecom-China Unicom 5G joint build, with 1.5 million shared basestations and claimed capex savings of $56 billion.

What regulatory questions remain?

The Singapore deal would leave three mobile operators, which industry convention holds is the minimum required for sustainable competition. The New Zealand arrangement is structurally different, a network-sharing deal inside a market that already has only three operators rather than a corporate merger.

For both transactions, the central question is whether shared infrastructure delivers lower prices and broader coverage, or entrenches incumbent positions at the expense of smaller rivals. The Commerce Commission's review of the 2degrees-OneNZ proposal will be the first formal test in New Zealand.

Both deals remain subject to negotiation and regulatory approval, with the New Zealand Commerce Commission's decision expected in 2025.