The European Union has levied a fine of 500 million euros (approximately $539 million USD) against Apple Inc. following a multi-year antitrust investigation. The investigation was sparked by complaints made in 2019 by music streaming service Spotify, which claimed that Apple’s control of the iOS App Store gave unfair advantage to its own Apple Music service.

Specifically, Spotify took issue with Apple policies that prohibit iPhone apps from directing users to cheaper payment options outside Apple’s payment system for in-app subscriptions. Apple requires apps to use its own payment system for subscriptions, allowing it to take a commission of up to 30%, which Spotify argued made Apple Music’s subscription cost lower than competitors.

While the fine of over half a billion dollars is substantial, it represents only a fraction of the potential penalties Apple faced. At one point during the ongoing investigation, the EU had threatened fines of up to 10% of Apple’s $40 billion in global annual turnover for violation of EU competition law.

Both Apple and the European Commission declined to comment directly on the reported fine when contacted. However, Apple spokesperson Hannah Smith had previously stated last February that Apple believed the EU investigation “has no merit.” Meanwhile, Spotify did not respond to a a request for comment on the EU’s antitrust ruling made partially in response to its complaints against the tech giant.

The fine closes one chapter in the ongoing battle between Apple and app developers over its control of iOS via the App Store. However, Apple still faces further lawsuits and regulatory scrutiny globally in places like the UK and USA around the fees and restrictions its has imposed in the name of security and user experience.