Greenhill¡¯s 75th-place ranking for global mergers advice this year didn¡¯t deter Mizuho Financial Group from paying more than double the market price for the U.S. boutique bank.

Facing rock-bottom interest rates and lackluster returns at home in recent years, Mizuho and some of Japan¡¯s biggest banks are seeking to make inroads into the world¡¯s largest fee pool, even if they have to pay a premium for the assets.

Sumitomo Mitsui Financial Group last month agreed to triple its stake in Jefferies Financial Group, while Mitsubishi UFJ Financial Group, Japan¡¯s biggest bank, has a more than decade-old alliance with Morgan Stanley.