MIG tracks an index that uses Moodys owned credit risk metric to identify investment grade corporate bonds that exhibit a low risk of being downgraded, and offer an excess spread over its fair value. The underlying index is comprised of USD-denominated bonds issued in the US domestic market by US and non-US issuers. Weightings are capped at 25% per business sector and 5% per issuer of corporate bonds. Excess weights are redistributed proportionally across all other uncapped corporate bonds. Selected bonds must have a minimum of 12 months to final maturity to remain included in the index. Bonds downgraded to non-investment grade are removed from the index at each monthly rebalance.