Eight companies are under formal investigation by the UK's Competition and Markets Authority (CMA) over concerns about online pricing tactics, marking the regulator's first major enforcement action under its strengthened consumer protection powers. The firms - StubHub, Viagogo, AA Driving School, BSM Driving School, Gold's Gym, Wayfair, Appliances Direct and Marks Electrical - are being examined as part of a wide-ranging review into how businesses display and structure online prices.