Shinsei Bank's board could meet this week to discuss a possible issuance of stock warrants to existing shareholders to dilute the holdings of SBI, which already owns 20% of the Tokyo-based lender, Nikkei said without citing sources.

The bank would then seek shareholders' approval for the measures in November, it said.

Shinsei Bank is also talking to potential white knights, including Seven & i Holdings and Sony Group Corp, Nikkei reported.

Shinsei Bank had no immediate comment on the report.

Sony and Seven & i, which both have banking businesses, could not be reached for comment outside business hours.

SBI last week announced https://www.reuters.com/article/shinsei-bank-sbi-idUSKBN2G50JF an offer to buy a near majority stake in Shinsei Bank to take effective control of the lender, as SBI aims to become Japan's fourth largest banking group.

SBI plans to lift its stake to up to 48%, offering 2,000 yen per share, a 39% premium over the price before the announcement. It plans to keep the lender listed after the tender offer.

SBI's large premium may make it tough for Shinsei Bank to win the required majority support from shareholders for its defence measures, analysts say.

They also say it would be hard to find rival suitors for the small bank which is still struggling to repay public funds it received during Japan's 1990s banking crisis.

SBI took a stake in Shinsei Bank after private equity investor JC Flowers & Co sold down its holding in 2019.

(Reporting by Makiko Yamazaki, Tim Kelly and Ritsuko Ando; Editing by Emelia Sithole-Matarise and Edmund Blair)