The iBoxx £ Collateralized & Corporates is designed to measure the performance of invesement grade, GBP-denominated bonds, with minimum amounts outstanding of GBP 100 million for bonds settled before or on Dec. 31, 2010, and GBP 250 million for bonds settled after Dec. 31, 2010. Securities must have a remaining time to maturity of at least one year at rebalancing. The index includes debt issued by public and private corporations as well as collateralized instruments, including covered bonds and securitized bonds.