iShares Long-Term National Muni Bond ETF(AMEX:LMUB)

LMUB aims to replicate the performance of an index, which reflects US dollar-denominated investment-grade tax-exempt debt issued in the US Muni market. Underlying securities must be rated at least BBB- by S&P to be included in the index. Bonds also require a minimum initial offering of $50 million, at least $10 million in outstanding face value, a term to maturity of 12 years or more, a minimum of three years until the next call date, and a fixed coupon schedule. Interest payments from the securities selected are exempt from federal income, federal Medicare contribution tax, and AMT. Holdings are market-value weighted and undergoes monthly rebalancing while using a capping method to mitigate concentration. The fund uses a representative sampling strategy to manage the portfolio. Up to 10% of the fund assets may be used in derivatives to help track the index or other iShares funds that provide similar exposure.