Apple found itself the target of EU antitrust investigations into its App Store and Apple Pay on Tuesday (June 16).
It comes as the bloc targets online gatekeepers over alleged anti-competitive business practices aimed at blocking rivals.
The European Commission said one investigation would look into the mandatory use of Apple's in-app purchase system, and rules that stop app developers from informing iPhone and iPad users of cheaper options elsewhere.
The case came after a complaint from Swedish music streaming service Spotify last year.
It said Apple was unfairly restricting rivals to its own streaming service, Apple Music.
Another point of frustration was a 30% levy imposed on app developers.
EU Competition Commissioner Margrethe Vestager said it appears Apple has taken up a so-called 'gatekeeper' role when it comes to the distribution of apps and content to users of Apple devices.
The second case focuses on terms and conditions for how mobile payment service Apple Pay should be used in merchants' apps and websites.
Brussels will look at the firm's refusal to allow rivals access to the payment system.
Regulators are also concerned that Apple Pay is the only mobile payment service allowed to use 'tap and go' functions on iPhones.
Apple has criticised the investigations.
The tech giant said the complaints were 'baseless', and made by a handful of companies who 'don't want to play by the same rules as everyone else'.