The tech giant could be compelled to allow competing app stores within the United Kingdom.
The iPhone maker could be required to permit rivals to operate their own application platforms on iPhones across Britain, following a decision from the market watchdog.
This would be a significant change to Apple's well-known "closed system" where apps can only be installed from its own official marketplace.
But the Competition and Markets Authority has classified both Apple and Google as having "dominant market position" - effectively saying they have a lot of power over mobile platforms.
Watchdog Assessment
The CMA said the tech firms "could be restricting progress and competition".
But the authority emphasized it did not "determine or presume misconduct" from the firms.
"The app economy contributes one and a half percent of the UK's GDP and supports around 400,000 jobs, which is why it's essential these sectors function properly for enterprises," stated a senior official from the competition authority.
Approximately ninety to one hundred percent of British smartphones run on the two tech companies' operating systems, creating what the authority calls an "virtual monopoly".
According to recent analysis, nearly half of British smartphone users own an Apple device - which runs Apple's iOS - with the vast majority of the rest using the Android OS.
The Company's Response
The regulatory probe examined how prominent Apple and Google's own apps are compared with competitors - as well as their web applications and operating systems.
It is unclear what changes the authority will look to request, but earlier it published roadmaps detailing possible actions it could take.
These include mandating it to be easier for people to transition between Apple and Android devices, and for both companies to rank apps "fairly and openly" in their app stores.
Apple particularly may be required to permit third-party marketplaces on its devices, and let people to download programs directly from developer sites.
This would mirror a similar ruling in the European Union, which previously imposed measures against Apple for anti-competitive behaviour.
Apple warned the UK could lose access to receiving updates - as has happened in the European Union - which the organization blames on strict rules.
For example, some Apple Intelligence features which have been launched in other regions are not available in the European market.
"Apple faces intense rivalry in every sector where we do business, and we work tirelessly to create the finest offerings, solutions and user experience," the company said in a release.
"Britain's implementation of European regulations would undermine that, resulting in consumers with reduced data protection and safety, slower availability to latest functions, and a fragmented, less seamless experience."
Google's Standpoint
Android users can currently use third-party app stores - though critics say they are not as smooth as the company's official application marketplace.
The CMA's roadmap said Google may have to "change the user experience" of downloading apps directly 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 company policy executive stated.
The representative said "the majority" of Android users use alternative app stores or download apps directly from a developer's website, and asserted there is a much wider selection of apps offered for Android users compared to those on Apple devices.
"Currently available are 24,000 Google-compatible devices from thirteen hundred device makers globally, facing strong rivalry from Apple's platform in the UK," the representative added.
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 opens up competition.
But advocacy organizations said curbs on these companies' power in other countries "currently assist enterprises to develop and giving customers more choice".
"Their dominance is now causing real harm by limiting options for users and market rivalry for businesses," stated a policy expert.