The European Commission has launched an investigation into Spotify's claim that Apple is abusing its position as gatekeeper of the App Store to push people towards its own Apple Music service.
Spotify filed an antitrust complaint with the European Union's competition commission in March, accusing Apple of "tilting the playing field to disadvantage competitors".
The complaint centres on the so-called "app tax", which requires Spotify and other digital services to pay a 30% levy on purchases made through the Apple App Store.
The policy applies to Spotify and other music subscription services such as Deezer and YouTube Music, but not other apps like Uber and Deliveroo.
"If we pay this tax, it would force us to artificially inflate the price of our Premium membership well above the price of Apple Music," said Daniel Ek , chief executive of Spotify.
"To keep our price competitive for our customers, that isn't something we can do.
"As an alternative, if we choose not to use Apple's payment system, forgoing the charge, Apple then applies a series of technical and experience-limiting restrictions on Spotify."
After considering the complaint, the EC has decided to launch a formal antitrust investigation into Apple's conduct, according to a report in the Financial Times .
If Apple is found to be in breach of EU competition rules, it could be faced to change its business practices and pay a big fine - up to 10% of its global turnover.
However, these investigations often take years to resolve, and many companies end up avoiding fines by offering to settle the probes with binding promises of behavioural change.
Spotify announced last week it has now has 100 million paying subscribers around the world - double the number of Apple Music.
Unlike Spotify, which offers a free plan that includes advertising, Apple Music is available only by paid subscription.
