Toshiba Corp.’s Chief Executive Officer Nobuaki Kurumatani will be replaced by Chairman Satoshi Tsunakawa, an abrupt leadership reshuffle that casts doubt over buyout offers that could value the Japanese icon at around ¥2.3 trillion.

Toshiba said the changes are effective immediately in an announcement Wednesday. The company will soon begin considering successors for Tsunakawa, who returns to the CEO job he held previously, said Osamu Nagayama, chairperson of the board, during a news conference in Tokyo.

The decision came as factions within the conglomerate mounted resistance to a preliminary buyout offer from CVC Capital Partners — where Kurumatani previously worked as Asia chief. Some executives felt the offer undervalued a storied Japanese corporation that still held valuable energy and semiconductor assets, according to people familiar with matter, who declined to be identified discussing internal issues. Separately, private equity firm KKR & Co. is exploring a rival offer for Toshiba.