Wall Street Deals Show Unfulfilled Ambition of Japan’s Megabanks

Greenhill & Co.’s 75th-place ranking for global mergers advice this year didn’t deter Mizuho Financial Group Inc. from paying more than double the market price for the US 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 up for the assets.

Sumitomo Mitsui Financial Group Inc. last month agreed to triple its stake in Jefferies Financial Group Inc., while Mitsubishi UFJ Financial Group Inc., Japan’s biggest bank, has a more ...