The European Commission has fined a group of zip and other fastener manufacturers €328.6 million euros ($458 million) for running an illegal cartel.

Six companies and a German trade group have been punished for fixing price hikes, setting price floors, sharing customers, carving up markets and exchanging sensitive information.

The companies – YKK, Prym, Coats, Scovill, A. Raymond, Berning und Soehne and German trade association Fachverband Verbindungs und Befestigungtechnik – also make fasteners such as rivets and snap buttons for footwear and clothing as well as machines for attaching them.

Japanese company YKK received the largest fine (€150 million), followed by Coats (€122 million) and Prym (€40.5 million).

"It is unacceptable that the major fastening technology producers colluded for such a long time [21 years in one case] to maintain artificial price levels and to share customers and markets," said competition commissioner, Neelie Kroes.

Ms Kroes has launched a "no-tolerance" crackdown on such cartels, imposing record fines against those caught in wrongdoing.