Citigroup Inc. (commonly known as Citi) is a major American multinational investment bank and financial services company headquartered in New York City, formed on October 8, 1998, through the historic merger of Citicorp (parent of Citibank) and Travelers. As the third-largest banking institution in the U.S. by assets, it is part of the "Big Four" banks and is considered a systemically important, "too big to fail" institution, managing roughly $2.8 trillion in assets. The company operates through two main divisions: the Institutional Clients Group (investment and corporate banking) and Personal Banking and Wealth Management (which includes Citibank and its credit card business). Its roots trace back to 1812 when the original City Bank of New York was chartered, and it grew to become the largest U.S. bank by 1895, pioneering innovations like compound interest savings (1921), unsecured personal loans (1928), and the negotiable certificate of deposit (1961). Citi also made history as the first U.S. bank to open an overseas branch (in Buenos Aires, 1914) and introduced the "Everything card" in 1967, which later became MasterCard. Today, it ranks among the world's top global investment banks and is a key player in the Bulge Bracket.