Apple is expected to be hit by a ban on its App Store rules that govern some music-streaming services and a potential hefty fine from European Union regulators, Bloomberg News reported Wednesday.

EU authorities are putting the finishing touches to a decision that would prohibit Apple’s practice of blocking music services from pushing their users away from the App Store to alternative subscription options, the report said, citing people familiar with the investigation.

The decision is slated for early next year and Apple could face a fine of as much as 10% of its annual sales, Bloomberg reported.

The probe was sparked by a complaint nearly four years ago from Sweden’s Spotify Technology, which claimed it was forced to ramp up the price of its monthly subscriptions to cover costs associated with Apple’s App Store rules.

The European Commission filed a chargesheet against Apple earlier this year, saying the conditions are unnecessary and mean customers may end up paying more.

Apple did not immediately respond to a Reuters request for comment. A spokesperson from the European Commission declined to comment.

Apple shares were marginally up in afternoon trading.