Chubu Electric Power
Hayakawa Electric was absorbed into , which was later nationalized and merged with other electrical producers into the . After the breakup of Nippon Hassoden at the end of World War II into various regional power utilities, the bulk of the dams on the Ōi River came under the control of Chubu Electric Power. However, only the Tashiro Dam was given to Tokyo Electric Power due to its previous owner, Tokyo Dento.