More than 10 major water-treatment plant makers, including Mitsui Engineering & Shipbuilding Co. and Mitsubishi Heavy Industries Ltd., were searched Tuesday by the Fair Trade Commission on suspicion of repeatedly rigging bids for contracts from local governments.
Also raided were Sumitomo Heavy Industries Ltd., JFE Engineering Corp., Kubota Corp., Ebara Corp., Hitachi Zosen Corp., Takuma Co. and Ataka Construction and Engineering Co.
Most of the companies confirmed they were being searched by the antimonopoly watchdog but declined comment on the reason.
The firms are suspected of conspiring to select bid winners and fix bid prices for contracts for building water-treatment plants, including sewer systems, from local governments in order to prevent real competition, keep bid prices high and share out the contract orders among them, sources said.
Orders worth more than 30 billion yen are believed to be involved, the sources said.
Mitsui Engineering, Mitsubishi Heavy, Sumitomo Heavy, JFE Engineering and Hitachi Zosen were indicted in June for rigging bids for bridge orders.