The European Commission has decided to open a phase II investigation into the merger between Sony and BMG. Recall that the earlier decision approving the merger in July 2004 was annulled by the CFI last summer. The CFI went quite far in that case, allowing the Commission to indirectly prove the existence (prior to a merger) of collective dominance in a given industry. A few months ago, I questioned whether the annulment was really a blow for the Commission, as was argued by certain observers. In fact, today's decision may confirm my early analysis :). The CFI's ruling relaxes the constraints which in the past prevented the Commission from threatening the music majors' oligopoly (sthing which the Commission had unsuccesfully tried to do in previous merger decisions). Today's decision raises further the risk that the Sony/BMG merger be jeopardized long after its implementation, paving the way to heavy ex post deconcentration measures (which would either come from a prohibition decision or from modifications submitted by the parties during the procedure).