Citigroup Inc. will move its Japanese retail banking unit's headquarters to Tokyo's Shinjuku Ward from Shinagawa in 2014 to increase floor space and cut costs, according to an internal memo obtained by Bloomberg News.

Employees at the retail banking and credit card businesses will start moving around July 2014 to Shinjuku Eastside Square, which was completed this year, from the 20-year-old Sea Fort Square, according to the memo, whose contents were confirmed by Tokyo-based spokeswoman Mika Nemoto.

Citigroup joins Morgan Stanley in relocating to new buildings in Tokyo's main business centers. Rents in the capital have fallen to ¥16,763 per "tsubo" (3.3 sq. meters) in June from ¥17,292 a year earlier, according to office brokerage Miki Shoji Co.

"The much larger floor size of Shinjuku Eastside Square will allow more groups to sit on the same floor, enhancing teamwork and efficiency," Citigroup Japan Holdings Corp. CEO Peter Eliot says in the memo addressed to employees in Japan.

Shinjuku Ward is home to the Tokyo Metropolitan Government's offices and the world's busiest train station, which sees an average of 3.64 million travelers pass through daily, according to Guinness World Records.

Morgan Stanley also is planning to relocate its Japan operations to the city's Otemachi business district from Ebisu by early 2014 because rents are "attractive," according to a memo obtained by Bloomberg News in April.

Citibank Japan Ltd. had ¥3.5 trillion in deposits as of March 31, according to its website. It has 1,800 employees and 38 branches.