Mitsubishi Estate Co., Japan's largest developer by value, may buy property managers to more than double assets under management to ¥4 trillion ($40 billion) within six years as Tokyo commercial rents slow.

Mitsubishi Estate, the main landlord in Tokyo's priciest business district, is in talks to buy or form an alliance with a number of fund management companies, Chief Executive Officer Keiji Kimura said in an interview in Tokyo.

"We are looking into M&A opportunities in the U.S., Europe and Asia including Japan," Kimura said March 12, without giving details. "It would be great to create a global network by buying property investment companies."