The U.K.’s antitrust authority closed investigations into Google’s Play Store and Apple’s AAPL 0.27 %increase; green up pointing triangle App Store as it prepares for the rollout of new rules that give the watchdog greater powers to boost competition in digital markets. The Competition and Markets Authority said Wednesday that it expects to consider competition concerns regarding the U.S. tech giants’ app stores under a new regulatory regime after the U.K.’s Digital Markets, Competition and...