The tech giant could be compelled to allow rival application marketplaces in UK.
Apple may have to allow rivals to operate their own app stores on iPhones in the UK, after a decision from the competition regulator.
This represents a major shift to Apple's well-known "walled garden" where apps can only be downloaded from its own official marketplace.
But the UK competition watchdog has designated both the tech giants as having "strategic market status" - indicating they have a lot of power over smartphone ecosystems.
Watchdog Assessment
The regulator said the tech firms "may be limiting innovation and market rivalry".
But the authority emphasized it did not "find or assume misconduct" 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 crucial these sectors function properly for business," commented a senior official from the CMA.
Around ninety to one hundred percent of UK mobile devices run on Apple or Google's mobile platforms, creating what the authority calls an "virtual monopoly".
Based on current data, 48.5% of UK mobile owners own an Apple device - which runs the iOS operating system - with the vast majority of the rest using the Android OS.
Apple's Reaction
The regulatory probe examined how dominant 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 regulator will look to request, but earlier it published roadmaps detailing possible actions it could take.
These comprise requiring it to be more straightforward for people to transition between Apple and Android devices, and for both companies to rank apps "in a fair, objective and transparent manner" in their app stores.
The Cupertino company particularly may be required to allow third-party marketplaces on its devices, and let people to install apps straight from companies' websites.
This would follow comparable regulations in the European Union, which previously imposed measures against Apple for anti-competitive behaviour.
The technology firm cautioned the United Kingdom could face delays to receiving updates - as has occurred in the European Union - which the company attributes to strict rules.
For example, some AI capabilities which have been rolled out in other parts of the world are not accessible in the EU.
"Apple encounters 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 release.
"The UK's adoption of European regulations would weaken that, leaving users with weaker privacy and safety, delayed access to new features, and a fragmented, less seamless user journey."
Google's Position
Google device owners can currently use alternative marketplaces - though critics say they are not as smooth as Google's own Play Store.
The regulator's plan said Google may have to "change the user experience" of downloading apps straight from websites, as well as "eliminate barriers" when using third-party platforms.
"There appears to be no the justification for the current classification," a Google competition lead stated.
The executive said "the majority" of Android users use third-party platforms or install applications straight from a developer's website, and claimed there is a much wider selection of applications available for Android users versus those on iOS products.
"Currently available are twenty-four thousand Google-compatible devices from thirteen hundred device makers globally, facing intense competition from iOS in the UK," the representative continued.
Google's platform is an freely available software, which means developers can utilize and develop on top of it for no cost.
The company argues this means it promotes competition.
But consumer groups said restrictions on these companies' power in different nations "currently assist businesses to develop and giving consumers more choice".
"Their dominance is now creating genuine problems by limiting options for users and competition for companies," stated a consumer advocate.