The letter from Akihiro Watanabe, chairperson of the board, and Jerry Black, chairperson of Toshiba's special committee looking at strategic alternatives, added there was no assurance that a deal would be reached.

Toshiba is "planning to receive binding and bona-fide proposal(s) and shall be making strong efforts to arrive at a conclusion as early as possible after necessary negotiations," the letter said.

Sources have told Reuters that the company's preferred bidder, Japan Industrial Partners (JIP), was moving closer to securing financing from banks for a buyout. A deal is expected to value the industrial conglomerate at around 2.2 trillion yen ($16 billion).

The Nikkei newspaper reported on Thursday that JIP was likely to receive 1.2 trillion yen in loans and that the core banking units of Sumitomo Mitsui Financial Group Inc and Mizuho Financial Group Inc would each lend 450 billion yen.

Financial services group Orix Corp, chipmaker Rohm Co Ltd and Japan Post Bank Co Ltd are among Japanese companies likely to join JIP in its bid, sources have previously said.

Shares in Toshiba, whose businesses span nuclear power, defence technology and which owns 40% of memory chip maker Kioxia Holdings, were up 1.7% in mid-morning trade.

($1 = 137.3900 yen)

(Reporting by Elaine Lies; Editing by Edwina Gibbs)