Tata Consultancy Services (TCS) signed an agreement with Citigroup Inc to acquire its captive BPO-Citigroup Global Services (CGSL) for $505 million (around Rs 2,424 crore) in an all-cash transaction. In addition to the sale, Citi has signed an agreement with TCS to provide, through CGSL, process outsourcing services to Citi and its affiliates in an aggregate amount of $2.5 billion over a period of 9.5 years.