Four Japanese labels have filed lawsuits seeking nullification of a July 24 ruling by the government's Fair Trade Commission that they violated the Antimonopoly Law by allegedly preventing other companies from entering the master-ringtone business.

In separate lawsuits filed at the Tokyo High Court on Aug. 25, Sony Music Entertainment (Japan), Avex Network, Victor Entertainment and Universal Music Japan denied they have conspired to monopolize the master-ringtone business by supplying content exclusively to Tokyo-based content aggregator/distributor Label Mobile, which they jointly own.

In a statement, Sony said that since 1999 it has been distributing its content digitally on its own, rather than consigning such distribution to other firms through licensing deals.

"We have not been in conspiracy with the three other labels to block chaku-uta [master ringtone] service firms' entry [into the market]," Sony said in a statement, "but have made our own decisions to reject the chaku-uta service firms' requests. We hope that our assertion that there was no such conspiracy will be proved through the court procedures."