The mainland has fined 10 Japanese companies a total of 1.24 billion yuan (HK$1.56 billion) for violating the antitrust law by fixing prices for car parts and bearings. Eight Japanese parts makers and four makers of bearings were found guilty of collusion, the National Development and Reform Commission (NDRC), the top economic planning agency, said in a statement on its website yesterday. The heaviest fine handed down - 290 million yuan - was imposed on parts maker Sumitomo Electric. The statement said the fine was equivalent to 6 per cent of Sumitomo Electric's revenue on the mainland last year. Bloomberg said it was the biggest antitrust penalty levied on a single company in the mainland. Under the antitrust law, a company found to have engaged in illegal pricing practices can face a fine equivalent to between 1 per cent and 10 per cent of its mainland revenue in the previous year. Parts maker Hitachi and bearings maker Nachi-Fujikoshi were exempted from penalties because the two took the initiative to report the monopoly agreement and provide proof to regulators, the statement said. NDRC secretary general Li Pumin said: "No matter whether they are domestic or foreign companies, they will be investigated and face penalties if they violate the antitrust law." Investigators found the Japanese parts makers had manipulated prices from January 2000 to February 2010, while the bearings makers had done so from 2000 to June 2011. The other companies fined were Mitsubishi, Mitsuba, Furukawa, NTN, Yazaki, Jtekt, Denso, Aisan Industry and NSK. The components involved in the price-fixing were used in more than 20 models made by Toyota, Honda, Nissan, Suzuki and Ford, the statement said.