CWB represents the US convertible securities space with a market-value-weighted and market-value-selected portfolio. The fund only selects convertible securities, such as convertible bonds and convertible preferred stock with a minimum outstanding issue of USD 250 million, and must have at least 31 days until maturity. The securities must be a non-called, non-defaulted security but may include investment grade, below investment grade or unrated securities. The index rebalances monthly.