Tata Consultancy Services (TCS), India's top software services exporter, has reached an agreement with US-based Citigroup to acquire all of the latter's interest in Citigroup Global Services Ltd. (CGSL) for US$ 505 million.

CGSL, the India- based back office arm of Citigroup Inc. (C) is one of the largest providers of BPO services within the Banking and Financial Services (BFSI) sector, providing end-to-end process management across the BFSI spectrum and a broad array of services to Citi's consumer, corporate and global wealth management businesses world wide. 

As a part of contract, TCS will provide application development, infrastructure support, help and other business process outsourcing services through CGSL to Citigroup and its affiliates. The value of the work has been estimated around US$ 2.5 billion over a period of nine and a half years. 

Citigroup Global has over 12,000 employees based in India and it expects to generate revenues of about $278 million in 2009.