A dissenting opinion written by Justice Neil Gorsuch and joined by other conservatives on the court agreed with Apple's argument that developers, not the company, sell to consumers and that the lawsuit is based on "pass-on" liability.
The lawsuit was filed by iPhone users who must purchase software for their smartphones exclusively through Apple's App Store.
Financially, the injunction is expected to force Apple to reduce the commission rate that it charges on apps, which now sits at 30%.
The decision also could let consumers sue Amazon by arguing that the fees it charges third-party sellers inflate the prices of products, said Hal Singer, an economist at Econ One Research Inc. and a senior fellow at the George Washington Institute of Public Policy.
Apple, also backed by the U.S. Chamber of Commerce business group, had sought to dismiss the case, arguing the plaintiffs lacked the required legal standing to sue.
If you're an Apple iPhone user in the USA, the update to version 3.1 of the Apple Support app adds a useful new feature.
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With Gayle missing, Shan will look to Jay Rodriguez to spearhead the frontline. I'd expect them to be a little more open", Smith told BBC WM 95.6.
Justice Brett Kavanaugh wrote in the Court's opinion, "Apple's line-drawing does not make a lot of sense, other than as a way to gerrymander Apple out of this and similar lawsuits".
It's worth noting that the Supreme Court did not rule Apple a monopoly, but rather allowed the suit to proceed. According to the company, the App Store is the "safest, most secure and trusted platform for customers".
Illinois Brick was a ruling in a 1977 case, which saw the government of Illinois filing a suit against eleven concrete brick manufacturers, alleging that they had conspired around price fixing while selling materials to the state.
And Apple faces charges in Europe of abusing its platform by discriminating against rival apps, including one complaint from streaming music service Spotify. The vast majority of apps on the App Store are free and Apple gets nothing from them.
Well now, the bigger question is: what does Apple - and Google - actually do if the plaintiffs win the case? You can read the entire decision related to the case here. Tens of thousands of developers create the software and set the price, Apple says.
Regardless, this means that, since it's no longer considered an intermediary, consumers can pursue the case against Apple. Instead of the 30 percent commission it gets now, it could be that a lower amount would be deemed more "competitive".
But the mess of figuring out who can claim what, and how much, for what app in what timeframe when you are talking about tens of thousands of companies and millions of customers is not something that anyone really wants to contemplate right now.