The ETRACS Alerian MLP Infrastructure Index ETN Series B is senior unsecured debt securities issued by UBS that provide exposure to potential price appreciation in the Alerian MLP Infrastructure Index. The index, comprised of 22 energy infrastructure master limited partnerships, is a subset of the Alerian MLP Index. The index refers to the master limited partnerships included in the Alerian MLP Infrastructure Index as the “index constituents.” It constituents earn the majority of their cash flow from the transportation, storage, and processing of energy commodities. The index is intended to provide diversified exposure specifically to infrastructure investment.