The latest rejection of the offer is from Mackenzie, who owns a 7.5 per cent stake, and follows those of Southeastern Asset Management, Harris Associates and Orbis, which own shares of 6.6 per cent, 7.5 per cent and 6.9 per cent respectively.
All of the banks, which represent Nikko's four largest shareholders, have cited Citigroup's valuation of $10.8 billion, or 1,350 yen per share, as too low.
Mackenzie has nominated a price of 1,700 yen or above as the share price it would be seeking.
Some market analysts now perceive that Citigroup's best chance of taking over the scandal-hit brokerage is if the company is delisted, which may cause share prices to drop and thus make shareholders more amenable to the offer.
Citigroup's interest in acquiring a majority stake in partner Nikko comes after the public standing of two companies was damaged by an accounting scandal that led to the resignation of six of top staff in December last year.
The six men are alleged to have issued falsified profits reports for the financial year ending March 2005.