Bain Capital is closing in on an $8bn deal to acquire Hitachi Metals after a consortium led by the US private equity group was granted exclusive negotiating rights for the Tokyo-listed materials group, according to people with direct knowledge of the discussions.

The expected deal, which has been under discussion since last August, will involve Hitachi selling its approximately 53 per cent stake in Hitachi Metals, which has historically been one of the Japanese conglomerate’s most important subsidiaries.

The sale of its majority shareholding in Hitachi Metals would take the parent company one step closer to clearing its books of stakes in its listed subsidiaries. Investors have identified that goal as a metric of corporate governance progress.