The preferred bidder to buy out Toshiba has offered to pay less than the widely regarded threshold of ¥6,000 a share, two sources said, indicating the premium for the Japanese conglomerate may not be as rich as investors had hoped.

A consortium led by private equity firm Japan Industrial Partners (JIP) was granted preferred bidder status by Toshiba in a second round of bidding on Oct. 7, though the conglomerate is still open to proposals from others, people familiar with the matter have said.

Conditions of JIP's proposal include retaining current management, a separate source said — a friendly offer for Toshiba Chief Executive Taro Shimada who aims to boost profit by beefing up data-related services.