•The CMA has opened a Phase 2 investigation into Nexfibre's £2 billion acquisition of Netomnia
•UK fibre consolidation enters regulatory phase as altnet competition shifts from build to buy
The fact
The UK's Competition and Markets Authority (CMA) has referred Nexfibre's proposed £2 billion acquisition of Substantial Group, the parent company of Netomnia, YouFibre and Brsk, to a Phase 2 investigation under the fast-track procedure. The regulator has set a statutory deadline of 15 December 2026.
The acquisition would combine Nexfibre's network with Netomnia's footprint, creating an operator serving more than 3.4 million premises and over 500,000 customers. Nexfibre, backed by Liberty Global, Telefónica and InfraVia Capital Partners, said the transaction would strengthen competition with BT Openreach and accelerate nationwide full-fibre deployment.
The fast-track review follows Nexfibre's request to bypass the standard Phase 1 investigation. Rival operator CityFibre supports the CMA's decision, arguing the merger would reduce infrastructure competition in areas where the two networks overlap. CityFibre said around 80% of Netomnia's network overlaps with its own footprint, while Nexfibre maintains the combined business would create a stronger long-term challenger to Openreach.
The assessment
The investigation reflects a structural change in Britain's fibre market. For much of the past decade, alternative network operators focused on building new infrastructure as quickly as possible. Today, that model is under pressure. Customer growth has slowed, network footprints increasingly overlap, and investors are demanding stronger returns. The industry is moving from network expansion to infrastructure consolidation.
Nexfibre's decision to request a fast-track Phase 2 review reflects that reality. Rather than pursuing a lengthy two-stage approval process, the company appears to have accepted that detailed regulatory scrutiny was inevitable. In return, it gains greater certainty over the review timetable, an important consideration for financing, integration planning and investor confidence. The strategy also highlights how regulatory planning is becoming part of competitive strategy, not simply a legal process.
For BTW readers, this case sets a template for European altnet consolidation. The CMA's decision will signal whether regulators accept market concentration as the natural next phase—or intervene to preserve infrastructure competition. Either way, the next round of fibre battles moves from construction sites to boardrooms and hearing rooms.
What to watch
Watch for the CMA's provisional findings and any proposed remedies before the final decision on 15 December. Requirements such as network divestments or behavioural commitments will indicate how regulators intend to balance investment, consolidation and long-term competition. The outcome is also likely to influence the pace of future mergers across the UK's alternative fibre sector.