UBS AG 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. The name "UBS" was originally an abbreviation for the Union Bank of Switzerland, but it ceased to be a representational abbreviation after the bank's 1998 merger with Swiss Bank Corporation. The company traces its origins to 1854, when the earliest of its predecessor banks was founded.

UBS is the biggest bank in Switzerland, operating in more than 50 countries with about 63,500 employees globally as of 2012. It is considered the world's largest manager of private wealth assets, with over CHF2.2 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 one the bank's largest shareholders. The bank also received capital from the Swiss government and through a series of equity offerings in 2007, 2008 and 2009.