The iBoxx Global Core Corporates (USD Unhedged) measures the performance of investment grade corporate debt denominated in USD, EUR and GBP from global issuers, regardless of domicile. Bonds must have a minimum amount outstanding of USD 500 million for USD-denominated bonds, EUR 500 million for EUR-issued bonds, EUR 1 billion for legacy bonds converted from pre-EUR currencies, GBP 250 million for bonds with first settlement date after Dec. 31, 2010, and GBP 100 million for bonds that settled on or before Dec. 31, 2010. Bonds must have a minimum time to maturity of one year at rebalancing, with USD-denominated bonds requiring a minimum time to maturity of 18 months at issuance. Bonds must have cash flows that can be determined in advance and the index excludes floating rate notes, asset-backed securities, mortgage-backed securities, municipal bonds, 144As, Brady bonds and restructured sovereign or sub-sovereign debt.