The takeover of the ticket resale website StubHub by its rival Viagogo has been provisionally blocked by the competition watchdog, throwing the future of the controversial $4bn (£3bn) tie-up into doubt. The Competition and Markets Authority (CMA) found the combined business would dominate the market for resold tickets, giving it the power to hike up fees in the absence of any meaningful competitor. It said Viagogo, which pressed ahead with the deal despite a warning from the watchdog, must now address its concerns, potentially by selling all or part of StubHub. Stuart McIntosh, the chair of the CMA inquiry group, 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.” The takeover has already been described as the “worst deal in history” after it was completed shortly before the pandemic shut down the vast majority of live events around the world. The CMA’s intervention could now see it unpicked entirely, unless Viagogo can come up with a remedy that will allay its concerns that the transaction would create a monopoly. The watchdog can order a full or partial sale of the business and even appoint a trustee to manage the sale. If that happens, the trustee has no obligation to reach a certain valuation, meaning Viagogo’s billionaire owner, Eric Baker, and his investors could be facing significant losses. The CMA is understood to have received submissions from music industry groups concerned about the power the combined company would wield, particularly in light of their past record on treatment of consumers. Both firms have drawn criticism from musicians such as Ed Sheeran, as well as from MPs, for repeatedly misleading consumers and exploiting alliances with powerful ticket touts to profit from fans’ devotion to their idols. The CMA has previously warned StubHub and Viagogo about their conduct. While its decision on the takeover relates to competition, it is allowed to consider the quality of service provided by the companies and how that might be affected by a combination. A Viagogo spokesperson said: “The CMA always considers a full range of remedy options for the UK market, and in the case of the Viagogo-StubHub merger, this is no different. “Our intention remains to provide event goers in the UK with the best possible service, and while we disagree with the provisional conclusion that the deal would reduce competition, we look forward to working with the CMA to deliver a comprehensive solution which addresses their concerns.” Adam Webb, the campaign manager at the music industry group FanFair Alliance, said: “Ultimately, this 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.” Viagogo has until 12 November to argue its case, with a final decision from the CMA due by 9 December.