UBS AG (SIX: UBSN, NYSE: UBS) is a Swiss global financial services company headquartered in Basel and Zürich, Switzerland. It provides investment banking, asset management, and wealth management services for private, corporate, and institutional clients worldwide, as well as retail clients in Switzerland. UBS was originally an abbreviation for the Union Bank of Switzerland, one of its predecessors; however, UBS ceased to be considered a representational abbreviation after its 1998 merger with Swiss Bank Corporation. The bank traces its origins to 1854 and the founding of its earliest predecessor banks.

UBS operates in more than 50 countries and has about 65,000 employees globally as of 2012. It is considered the world's second largest manager of private wealth assets, with over CHF 2.2 trillion in invested assets, a leading provider of retail banking and commercial banking services in Switzerland.

UBS suffered among the largest losses of any European bank during the subprime mortgage crisis and the bank was required to raise large amounts of outside capital. In 2007, the bank received a large capital injection from the Government of Singapore Investment Corporation, which remains the bank's largest shareholder. The bank also received capital from the Swiss government and through a series of equity offerings in 2008 and 2009.