Apple hasn’t been shy about offering third-party developers ways to boost their visibility in the iOS App Store — paid advertising placements and Apple-generated “feature” articles — but it insists that it isn’t manipulating its app search results to favor its own apps. Already facing international scrutiny for allegedly monopolistic practices with software developers, Apple said today that it uses a complex 42-factor system to surface apps during user searches, and deliberately obscures itsĀ mechanics to prevent third-party manipulation.

The revelation came in response to a Wall Street Journal report that Apple’s own apps are shown first in 60% of the App Store’s categories and in 95% of Apple subscription- or sales-generating categories, even when competing apps from Amazon and Google are higher-ranked or more popular. For instance, Apple Books ranks 168th in its category by downloads and has no user rating, but it displays above Amazon’s Kindle app, which has a 4.8-star rating from over 1.2 million users. Google’s top-ranked Maps app sits below Apple Maps in the App Store’s listings, despite Apple’s version not even ranking in the Navigation category’s top 100 apps.

Interest in Apple’s behind-the-scenes App Store dealings has peaked in recent months, as the company has faced renewed complaints from rivals such as Spotify and Netflix over its 30% take of app revenues. In March, Spotify filed a complaint against Apple with the EU over the fees, and Netflix refused to join the Apple TV Channels service, only months after brazenly pulling out of Apple’s iTunes billing system while continuing to offer subscription services directly to users. Apple has previously faced investigations by the FTC and other bodies over its revenue-sharing practices.

According to Apple, search results in the App Store are determined using 42 factors, including an apparently heavy but unspecified reliance on customer interest data. “Apple customers have a very strong connection to our products and many of them use search as a way to find and open their apps,” the company told the Journal. “This customer usage is the reason Apple has strong rankings in search, and it’s the same reason Uber, Microsoft and so many others often have high rankings as well.”

While Apple wouldn’t disclose the way its multi-factor algorithm actually works, it suggested that name matches and “customer behavior data” were among the elements, for whatever they’re worth. As frequent App Store users know, however, straight name searches for various apps often result in matches to different and competitive apps, calling into question the weight that Apple assigns to a direct name match.

Listing its own apps higher than competitors gives Apple an “upper hand” in a $50 billion market, the Journal claims, at a time when the company is pivoting to subscription revenues for growth. Apple held an event called “It’s Show Time” in March, focusing solely on a collection of self-branded news, game, credit card, and video services that it planned to roll out throughout 2019, in some cases challenging existing alternatives.