The tech giant may be forced to allow competing app stores within the United Kingdom.
The iPhone maker may have to permit competitors to operate separate application platforms on Apple devices in the UK, following a ruling from the competition regulator.
This represents a major shift to Apple's well-known "closed system" where applications can only be downloaded from its own App Store.
But the Competition and Markets Authority has classified both the tech giants as having "strategic market status" - indicating they have significant control over smartphone ecosystems.
Watchdog Findings
The CMA said the two companies "may be limiting progress and competition".
But the authority clarified it did not "determine or presume wrongdoing" from the firms.
"Mobile applications generates one and a half percent of the UK's GDP and supports around four hundred thousand positions, which is why it's essential these markets work well for enterprises," stated a senior official from the CMA.
Approximately ninety to one hundred percent of UK mobile devices run on the two tech companies' mobile platforms, creating what the authority calls an "virtual monopoly".
According to current data, nearly half of British smartphone users own an iPhone - which runs the iOS operating system - with the vast majority of the remaining users using Google's Android.
Apple's Reaction
The CMA's investigation examined how prominent Apple and Google's own apps are compared with competitors - as well as their web applications and platform software.
It is unclear what modifications the authority will seek to implement, but earlier it published roadmaps outlining possible actions it could take.
These comprise requiring it to be more straightforward for people to transition between iOS and Android devices, and for both companies to rank apps "fairly and openly" in their app stores.
Apple particularly may be compelled to allow alternative app stores on its products, and enable people to install apps straight from developer sites.
This would follow a similar ruling in the European Union, which previously imposed measures against the company for restrictive practices.
The technology firm warned the United Kingdom could face delays to receiving updates - as has happened in the EU - which the company blames on heavy regulation.
For instance, some AI capabilities which have been launched in other regions are not available in the European market.
"Apple faces intense rivalry in every sector where we operate, and we strive continuously to create the best products, solutions and user experience," the company said in a statement.
"The UK's adoption of EU-style rules would weaken that, leaving users with reduced data protection and security, delayed access to new features, and a divided, more complicated experience."
The Search Giant's Position
Google device owners can presently use alternative marketplaces - though commentators say they are not as user-friendly as the company's official Play Store.
The CMA's roadmap said the search company may have to "modify the interface" of installing applications straight from online sources, as well as "remove user frictions" when using third-party platforms.
"We simply do not see the rationale for today's designation decision," a Google policy executive stated.
The executive said "most" of Android users use alternative app stores or download apps directly from a creator's site, and claimed there is a far greater range of apps available for Google device owners versus those on iOS products.
"Currently available are twenty-four thousand Android phone models from thirteen hundred device makers worldwide, facing intense competition from Apple's platform in the UK," the representative added.
Android is an open-source operating system, which means creators can use and build on top of it for free.
Google contends this means it promotes competition.
But advocacy organizations said curbs on these companies' power in different nations "currently assist enterprises to develop and giving consumers more options".
"Their dominance is now causing real harm by limiting options for consumers and competition for companies," stated a policy expert.