Citigroup Inc. has agreed to sell its stake in Japanese call-centre operator Bellsystem24 to US private equity firm Bain Capital for 93.5 billion yen ($1.12 billion) as part of the company's strategy to sell off non-core assets in order to raise its capital.

Tokyo-based Citigroup Capital Partners Japan (CPJ), a private-equity arm of Citigroup is selling Japan's largest call centre operator Bellsystem24, which CPJ, known earlier as Nikko Principal had acquired Bellsystem24 in 2004 for 220 billion yen.

Citigroup said in a release that it had agreed to sell its 93.5 per cent stake in Bellsystem24 for 93.5 billion yen in cash in a tender offer to be launched by an acquisition corporation owned by investment funds advised by Bain Capital.

The tender offer will likely to be launched on or before 20 November and be completed on 30 December.

After completion of this transaction, Citigroup's assets will be reduced by $1.2 billion, in line with Citi's goal to reduce the assets in Citi Holdings while optimising their value.

The New York-based bank said that it is not expected to have a material impact on Citi's net income or its capital ratios.

The acquisition of Bellsystem24 by Boston-based private equity  firm with $60 billion of assets under management, will be the largest buyout made by a foreign private equity firm in Japan in nearly two years.

In June, Bain Capital acquired a 16 per cent stake in Chinese electronics manufacturer GOME Electrical Appliances  for $300 million, which is the second largest investment made by Bain in the China.

It had also teamed up with Chinese networking company Huawei Technologies in 2002 in a failed bid to acquire 3Com for $2.2 billion in cash, (See: Bain calls off 3Com deal as US objects to Chinese stake) which was acquired last week by Hewlett-Packard for $2.7 billion in cash. (See: HP to acquire networking-gear maker 3Com for $2.7 billion)

After securing exclusive negotiation rights earlier this month, Bain was widely expected to buy Bellsystem24 although it had to outbid other contenders like private equity firm including Kohlberg Kravis Roberts, which teamed up with trading house Itochu Corp and Permira and a team of CVC Capital and Blackstone.

In April 2009, Citigroup sold its Japanese brokerage unit Nikko Cordial broker Nikko Cordial, a fund management firm and a trust bank to the Sumitomo Trust and Banking as for $1.3 billion. (See: Citi seeks to sell its brokerage unit Nikko Cordial: report)

This year in Japan, including the Bellsystem deal, Citigroup will have raised a total of about $10.8 billion, according to the company.