Masako Shiono, spokeswoman for Mizuho, told Bloomberg: "We are certain we will accept the offer. Mizuho intends to maintain its good business relationship with Citigroup and Nikko, and we gave consent.''
The sale, which comes after Citigroup upped its initial offer to $14.43 per share, is likely to facilitate the US banking giant's $13.4 billion buyout bid for the scandal-hit Japanese brokerage amid opposition from the four biggest shareholders.
Citigroup's improved offer followed the Tokyo Stock Exchange's decision not to de-list Nikko after an accounting scandal in December of last year, which led to the resignation of six top-level staff.
However, Citigroup has ruled out upping its bid any further despite claims from the bank's four largest shareholders that the bank's offer "undervalues" the brokerage.
News of Mizuho's intentions comes after the bank has announced a cut in its earnings forecast by a quarter to $4.6 billion from an earlier projected figure of $6.1 billion, with bad debts incurred from loans blamed for the downturn.