Citigroup plans to boost the number of its branch locations in Japan by 40 percent to about 200, including those of recently acquired brokerage Nikko Cordial Corp., as the financial firm looks to move beyond a niche role in the world's second-largest economy.

The bank has tapped Howard Baker, a former U.S. ambassador to Japan, and Masajuro Shiokawa, a former Japanese finance minister, for advice on the expansion, it said on Wednesday.

Three years after Japanese regulators forced Citigroup to shut down its private banking business due to rules violations, the world's largest financial firm is attempting to rebrand itself for the Japanese market.

This month it relaunched its local unit, Citibank Japan Ltd., as a Japanese bank, becoming the first foreign lender to receive a license to operate as a local entity.

It has also begun to push beyond its base in upscale Tokyo, opening branches in suburban areas and regional cities.

The company has said it would double the number of Citibank branches to about 60 in the next several years.

Citigroup has about 140 locations across the country, including 32 Citibank outlets. Branches of Nikko Cordial, Japan's third-largest brokerage, account for the rest.

The company aims to lift the total number to about 200, spokeswoman Atsuko Yoshitsugu said, although she declined to specify a time frame.

Citigroup hopes to tap into Japan's mass affluent market -- individuals looking for investment products such as mutual funds and cross-asset portfolios, but not wealthy enough for the boutique services offered to clients with ultra-high net worth.

Total Japanese household financial assets amount to about $13 trillion, with much of that sitting in low-yield savings accounts. Banks, brokers and asset managers have been eager to draw those funds into investments.

The firm confirmed that Shiokawa, the former finance minister, would chair a panel to advise on its expansion strategy. Baker, a three-term Republican senator from Tennessee before he became U.S. ambassador, will serve as vice chairman.

Citigroup's Yoshitsugu declined to comment on media reports that Hiroshi Okuda, the former head of both Toyota Motor Corp. and Japan's most influential business lobby, would also serve on the panel.

Citigroup Japan