BRUSSELS (Kyodo) The European Union's executive body said Thursday it has opened a full-fledged investigation into a proposed merger between the music units of Sony Corp. and Germany's Bertelsmann AG.

Following a one-month review, the European Commission has decided to investigate whether the deal might "create or strengthen a collective dominant position" in the global recorded music market, the commission said in a statement.

In December, Sony Music Entertainment Inc., the world's No. 2 music group, and Bertelsmann's BMG reached a final agreement to set up a 50-50 joint venture, to be called Sony BMG.