The ETRACS Wells Fargo® Business Development Company Index ETN Series B due April 26, 2041 are senior unsecured debt securities issued by UBS AG. The index is intended to measure the performance of all business development companies listed on the NYSE or NASDAQ that satisfy specified market capitalization and other eligibility requirements. It refers to the business development companies included in the Wells Fargo® Business Development Company Index as the “index constituents.” The index is a proprietary index of Wells Fargo Securities, LLC.