Apple's expansion into services could test the hardware company in several ways — including the risk of making the company an even bigger antitrust target — because the company already tightly controls its ecosystems, especially the iPhone and iPad.

Why it matters: Companies have long-alleged that Apple and Google exploit their footing as owners of both the world's largest smartphone operating systems (iOS and Android) and some of the world's most popular apps (like Apple Music and Google Maps).

Driving the news: Dutch antitrust officials said Thursday that they would investigate whether Apple favors its own apps over those of its rivals.

In a statement, the Netherlands’ Authority for Consumers & Markets said it received indications from app providers that Apple abuses its position in the App Store, giving it a sufficient reason for launching a follow-up investigation.

The probe comes on the heels of a complaint filed by Apple Music rival Spotify last month. The Swedish music platform asked EU officials to look into whether Apple stifles competitive apps in its App Store, which it says harms consumer choice.

Between the lines: Apple's move into services is likely to create even more of these kinds of issues.

News publishers are also concerned about Apple's dominance in rolling out its new Apple News+.

Apple, for its part, said it is confident the Dutch agency's review "will confirm all developers have an equal opportunity to succeed in the App Store."

The big picture: It's never been clear whether having a monopoly over a particular platform presents an antitrust problem if the platform itself faces sufficient competition.

In this case, Apple dictates the terms and rules for the iPhone, but the iPhone itself has competition. Think Xbox or PlayStation as other examples of this.

For the most part, regulators have been hesitant to step in.

Yes, but: It’s not a settled issue. Europe has taken on Google over Android, and similar questions were also raised when Apple controlled both the iPod and iTunes and wouldn't let the device work with other services or the service work with non-iPod devices.

Go deeper: For tech, antitrust is a fatal distraction