The Supreme Court on Tuesday allowed a court order to take effect that could loosen Apple’s grip on its lucrative iPhone app store, and potentially affect billions of dollars in revenue a year.

The justices rejected Apple’s appeal of lower-court rulings that found some of Apple’s app store rules for apps purchased on more than 1 billion iPhones constitute unfair competition under California law.

The appeal stemmed from an antitrust lawsuit filed by Epic Games, maker of the popular Fortnite video game. Epic lost its broader claim that Cupertino, California-based Apple was violating federal antitrust law, and the justices also rejected Epic’s appeal Tuesday.

But in turning away Apple’s plea, the court lifted a hold on an order to allow app developers throughout the US to insert links to other payment options besides its own within iPhone apps. That change would make it easier for developers to avoid paying Apple’s commissions.

Epic, based in Cary, North Carolina, had claimed that Apple’s app store — which was launched in 2008, a year after the first iPhone went on sale — had turned into an illegal monopoly that stifles innovation and competition while generating billions of dollars in profit for Apple.

Epic tried to offer an alternative way to get its mobile app, attempting to evade the developer fees inside the app store, which collects a commission of 15-30 per cent on subscriptions and other digital transactions.

AP