Following its in-depth, ‘Phase 2’ investigation into the $4.05 billion (£3bn) merger of the two biggest secondary ticketing operators, Viagogo and StubHub, the Competition and Markets Authority (CMA) has reached a provisional decision that could lead to it requiring Viagogo to sell all or part of StubHub.

The CMA said Viagogo and StubHub, previously owned by eBay, are close competitors in an already very concentrated market with no significant additional competitors: “They are the only two companies of material size in the UK’s secondary ticketing market with a combined market share of more than 90%.”

Viagogo purchased StubHub in February and the CMA began its in-depth investigation in June after finding concerns during an initial probe.

The CMA said that among its concerns following the Phase 2 investigation are that the merger could result in a lower quality of service and reduced innovation in the sector. It also said the deal could lead to increases in fees for customers who resell or buy secondary tickets to live events.

CMA chair Stuart McIntosh said: “The evidence we’ve seen so far consistently points in the same direction – that Viagogo and StubHub have a market share of more than 90% combined and compete closely with each other. We are therefore concerned that their merger could lead to secondary ticketing customers facing higher fees and lower quality services. We’re now inviting comments on our provisional findings and possible remedies.”

Adam Webb campaign manager of anti-ticket touting campaigner FanFair Alliance welcomed the provisional findings: “Though poorly-timed and focussed predominantly on the US market, Viagogo’s $4.05bn acquisition of StubHub raises acute competition concerns in the UK. We are pleased the CMA has recognised this. Ultimately, the merger would bestow a hugely controversial business monopoly status in this country, and risk unpicking some significant progress made over recent years to clean up the secondary ticketing market.”