Citigroup (NYSE:C) is one of the world's largest diversified financial services firms, which means that it makes money by loaning out money and receiving interest on the loans.  In 2010, Citigroup reached a turning point in which the company was able to achieved its primary goal of returning to profitability, posting positive net income in each quarter and a full-year profit of $10.6 billion. The company was forced to alter its operations in order to reach this point. Citi sold branches such as CitiStreet, CitiBank, and its banking operations in Germany. In addition the company reshuffled and changed its management These efforts represent a shift away from an investment bank into a standard holding bank.
Citigroup operates in four regions include North America (including US, Canada, and Puerto Rico), EMEA (Europe, Middle East & Africa), Latin America (including Mexico, and Asia (including Japan). It's divided into two business: Citicorp, which encompasses Citi's core businesses, the Regional Consumer Banking Division and Institution Clients Group, and Citi Holdings, which overseas Brokerage and Asset Management, Local Consumer Lending, and Special Asset Pool, all of which are businesses which Citi wishes to shrink.
This division provides traditional commercial banking services. Lending opportunities are also available under this arm of Citi, including loans for housing, auto-financing, and for students. Citi also issues credit cards under the Visa, MasterCard, Diners Club, and American Express networks, with around 120 million cardholders globally.
This unit, also referred to as corporate and investment banking, offers financial advice to companies interested in raising capital or involved in mergers and acquisitions and provides clients with cash management and treasury services, such as streamlining multiple asset classes under one processing system. In addition, its Global Capital Markets division provides sales, trading, and research services, and is the second largest brokerage system in the U.S. 
Citi Holdings is the division put in place to handle the divestiture of assets that are generally unwanted on Citi's balance sheet. It exists to hold businesses which Citi does not consider to be its core businesses, which are held in Citicorp.
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The major players in Citi's league are Bank of America (BAC), Deutsche Bank AG (DB) and J P Morgan Chase (JPM). These firms typically operate on a business model that gradually introduces clients to complex financial services and solutions as the client matures. In this way, these banking firms try to cater to the client's entire life span by offering as many products as possible. For this reason some have identified this strategy as building "banking supermarkets." This mode of thinking has changed recently, as Citigroup increasingly focuses on its most profitable products, continues to cut costs and personnel, and relocates offices to regions that are experiencing robust growth.