Citigroup's corporate strategy aims to be the #1 global financial services firm by offering a one-stop-shop for all financial needs. This strategy involves coordinating many business lines across multiple sectors and countries. Citigroup uses four strategies - portfolio strategy for diversification, turnaround strategy through acquisitions, transferring skills across businesses, and sharing resources through cross-selling. However, Citigroup faces risks from its large size and scope, including potential issues with legacy systems, mixed strategies, and succession planning following the retirement of long-time CEO Sandy Weill. The document discusses both the potential advantages and disadvantages of Citigroup's strategy to become a highly diversified global financial conglomerate.