The Fair Trade Commission said it slapped around ¥740 million in fines on 36 companies, including one in the Tokyo Electric Power Co. group, for fixing bids related to power line construction.

Tepco group firm Transmission Line Construction Co. took a leading role in bid-rigging projects to build overhead power lines, while Tokyo-based Kandenko Co., a Tepco subcontractor, did the same for projects involving underground power lines, the antimonopoly watchdog said Friday.

TLC was fined around ¥110 million, Kandenko about ¥100 million and Osaka-based Sumitomo Electric Industries Ltd. roughly ¥30 million. The commission said Tepco officials encouraged or facilitated the bid-rigging.

The 36 firms, based in 13 prefectures, rigged bids for overhead and underground power line work as far back as January 2012 by deciding who the successful bidders would be beforehand.