The UK Competition and Markets Authority (CMA) has provisionally concluded that the proposed acquisition of Substantial Topco Limited by nexfibre—a joint venture between Liberty Global, Telefónica, and InfraVia Capital Partners—could result in a substantial lessening of competition in the wholesale fixed broadband market.
In an interim report released on October 2, 2026, the CMA’s Inquiry Group outlined concerns that combining nexfibre’s infrastructure with Substantial’s network footprint would significantly diminish wholesale options for internet service providers (ISPs). Substantial, which operates through subsidiaries Netomnia, Brsk, and retail provider YouFibre, possesses a network concentrated heavily across the Midlands and the North of England.
A central element of the regulator’s findings involved establishing the likely market scenario had the transaction not taken place. Following an analysis of bidding data and internal financial modelling, the CMA determined that alternative operator CityFibre would have likely acquired Substantial while divesting its retail arms to a third party. Under that counterfactual, CityFibre—a vigorous independent wholesale challenger—would have competed directly alongside Openreach and Virgin Media O2 (VMO2)/nexfibre across a broader geographical footprint.
The provisional findings indicate that the acquisition would reduce the proportion of overlapping network areas where three distinct wholesale competitors operate from roughly 32% down to 18%. The regulator highlighted that reduced wholesale competition ultimately leads to higher prices, reduced service quality, and fewer choices for end-consumers and local businesses.
While nexfibre and its parent entities argued that the transaction would deliver vital operational efficiencies, accelerate VMO2’s transition from cable to full-fibre (FTTP) infrastructure, and create a stronger counterweight to Openreach, the Inquiry Group rejected these claims. The panel concluded that any additional scale gained through the merger would be relatively small and insufficient to counter the negative impact on wholesale market dynamics.
The CMA emphasized that its provisional decision is specific to the network overlaps in this transaction and does not signal a general stance against wider consolidation within the UK alternative network (“altnet”) sector.
Interested parties have been invited to submit responses to the interim findings by October 23, 2026. Meanwhile, the merging entities must indicate within three working days whether they intend to submit a formal Phase 2 remedies proposal by October 16, 2026. The Inquiry Group is scheduled to deliver its final statutory report by December 15, 2026.