The nation's largest online shopping mall operator appears to be building an empire, or what its president calls a new zaibatsu in the world of Internet retail.

Rakuten Inc. announced in September its purchase of Mytrip Net Co., which specializes in online hotel and travel information services, for 32.3 billion yen from its parent company, shipbuilder Hitachi Zosen Corp. This was only one of Rakuten's aggressive expansion moves.

"We are trying to build a corporate group, like zaibatsu, capable of offering various services in the Internet business," Rakuten President Hiroshi Mikitani said.