The European Commission has fined Sony, Fuji and Maxell 75 million euros, about £54 million, for price fixing videotapes.
"Between 1999 and 2002, Sony, Fuji and Maxell managed to raise or otherwise control prices through a series of regular meetings and other illicit contacts", the European Union executive said in a statement.
"This decision sends two warnings to companies engaging in cartel activities."
Sony has fined 30% more than the other two companies, a total of 47 million euros, for trying to cover up the investigation. Fuji and Maxell co-operated and have been fined 13.2 million and 14.4 million euros respectively.
The "cartel" controlled 85% of the market in the professional videotape formats of the day, Betacam SP and Digital Betacam.