The EU has launched an inquiry into the high cost of CDs in Europe.
Five big music companies, five unnamed online sales outlets and 13 traditional retail companies are being investigated over claims that an illegal price-fixing cartel is in operation.
The Commission's experts want to establish why CDs are often significantly more expensive than in the US and why they are more expensive than cassette of identical music.
The inquiry will focus on how music companies share information and the way such information may have been used to fix prices artificially, in contravention of EU rules.
The announcement follows years of controversy over CD prices, with consumer organisations regularly lobbying Brussels for action.
Prices can vary widely for the same CD in different EU countries but the most glaring contrast is between the EU and the US.
CDs of the music of top stars can range from less than £10 in America to more than £14 in the EU.
A survey conducted by the UK Consumers' Association compared prices of the Britney Spears album Oops, I Did It Again and found that it cost on average £10.77 in America, and £12.08 across the EU.
A crackdown on EU pricing, with big fines for any companies found guilty of rigging prices, would add to the woes of an industry already faced with free internet downloading of music.
A fierce battle is raging over music copyright and the freedom of internet companies to offer artists' work for nothing, a right which the major music companies say is costing millions in lost royalties.