The Fair Trade Commission ordered Sekisui Chemical Co. and Mitsubishi Plastics Inc. on Wednesday to pay ¥11.7 billion in fines for forming a sales cartel for vinyl chloride pipes between 2004 to 2006.
Osaka-based Sekisui Chemical was slapped with a fine of about ¥7.96 billion, the biggest ever imposed for breaking the Antimonopoly Law. Tokyo-based Mitsubishi Plastics was fined about ¥3.72 billion.
The two companies said they have not yet decided whether to comply with the order.
The FTC said four other companies were also involved but stopped short of penalizing them without explaining why.
The six companies formed a cartel to raise the price of vinyl chloride pipes and related equipment by 5 percent to 15 percent on four occasions, according to the FTC.