Competition authorities in four jurisdictions have reviewed eight transactions since late 2023 tying leading AI labs to large technology companies, and nearly all were found to fall outside merger law. The UK's Competition and Markets Authority (CMA) cleared Microsoft's deals with OpenAI and Mistral, Amazon's partnership with Anthropic, and Microsoft’s deal with Inflection on the merits. Germany's Federal Cartel Office concluded Microsoft-OpenAI’s cooperation was not subject to merger control. Brazil's Administrative Council for Economic Defense (CADE) cleared Nvidia-Run:ai, Microsoft-Mistral and Google-Character.AI mergers on the same grounds in 2026. EU member states’ referral procedure concerning Microsoft’s acquisition of certain assets of Inflection was closed. The one exception: Brazil separately ordered a merger review of the Microsoft-Inflection deal, invoking a discretionary provision under Article 88(7) of the Competition Law. Merger review is organized around a threshold inquiry: does the deal give one company enough power over another’s strategic decisions to count as control? Frontier AI's ownership structure presents a different case, characterized by influence accumulated through minority stakes, exclusive supply arrangements and board-adjacent access that regulators have repeatedly found significant, yet insufficient to establish control. The reasoning the UK's CMA published on Microsoft-OpenAI shows the mechanism at work, finding Microsoft held a high degree of material influence over OpenAI's commercial decisions.