Apple‘s acquisition of Shazam has hit a major hurdle after the European Commission announced it would investigate the US$400 million deal.

The Commission, the European Union’s regulatory authority, will test whether the arrangement will give Apple a dominant position in the markets for music streaming and audio recognition.

“Our investigation aims to ensure that music fans will continue to enjoy attractive music streaming offers and won’t face less choice as a result of this proposed merger,” comments EU competition commissioner Margrethe Vestager.

Also, the commissioner’s office will want to learn whether the tech giant could gain access to sensitive customer data and lure consumers from its competitors.

After several months of negotiations, Apple confirmed last December it had reached a deal to buy the London-based Shazam, which execs described as “a natural fit” for Apple’s own music activities.

The Commission, however, decided to examine the purchase following requests from seven territories: Austria, France, Iceland, Italy, Norway, Spain and Sweden – the home of Apple Music’s rival, Spotify. Based on preliminary data provided by those seven markets, the Apple-Shazam union may have a significant adverse effect on competition.

The Shazam app, which lets users identify a recording by pointing a smart phone at the song, has been downloaded more than a billion times since its commercial rollout in August 2002.