The UK Competition and Markets Authority’s review and clearance of the proposed acquisition by Roche of Spark Therapeutics on 10 February 2020 is the latest example of the CMA scrutinising a merger with no obvious jurisdictional link to the UK. The case exemplifies how the CMA has started using the “share of supply test” as an all-purpose tool to assert jurisdiction over mergers – even when the target has little or no UK market presence. The Roche/Spark case is a strong reminder of the CMA’s broad review powers under the share of supply test, its willingness to assert jurisdiction over mergers, even on the basis of reasoning that may appear fanciful, and its keen interest in so-called “nascent competitors” – especially in the pharmaceutical and technology sectors.