The United Kingdom’s Competition and Markets Authority (CMA) announced on Wednesday that Google and Apple will face heightened scrutiny due to their “strategic” influence over mobile platforms, a move that could lead to regulatory changes aimed at boosting competition.

The CMA formally designated both U.S. tech giants with “strategic market status,” expanding oversight under new digital market regulations meant to curb unfair practices by major technology firms. The decision follows earlier investigations launched this year into Google’s Android and Apple’s iOS systems.

This classification was widely anticipated. The CMA first proposed it in July and sought public feedback before finalizing its decision. Google criticized the move as “disappointing, disproportionate and unwarranted,” arguing that Android has actually lowered costs for app developers by offering a unified operating system. “Following the CMA’s decision today, our mobile business in the UK faces a new and uncertain set of rules,” said Oliver Bethell, Google’s senior competition director. “The CMA’s next steps will be key to ensuring that the UK’s digital markets regime supports growth and innovation.”

The regulator has issued separate “road maps” for each company that outline possible measures to strengthen competition, such as ensuring fair and transparent app reviews and store rankings. It also suggested allowing developers to direct users to external payment methods outside app stores—an approach similar to that adopted by the European Union.

Apple expressed concern that the CMA’s plans could compromise user security and harm the U.K.’s “developer economy.”

Earlier this month, Google had already been assigned “strategic market status” in a separate probe into the company’s dominance in online search advertising, marking the first time the CMA invoked its expanded authority.

While the new designation does not imply any wrongdoing, it gives the regulator the ability to implement targeted interventions to promote fair competition and consumer protection.

The CMA noted that Apple and Google maintain an “effective duopoly,” with 90% to 100% of mobile devices in the U.K. operating on their platforms. The investigation identified several concerns, including inconsistent app reviews, unpredictable search rankings within app stores, and in-app purchase commissions reaching up to 30%.