MUB tracks the ICE AMT-Free US National Municipal Index and holds investment-grade bonds issued by US states, cities and other local governments. Interest is generally exempt from federal income tax, and may be exempt from state tax for residents of the issuing state, so the fund is mainly suited to investors in higher tax brackets who hold it in taxable accounts. The tax-exempt yield should be compared with the after-tax yield of taxable bonds. Credit quality is high on average, and returns depend mainly on interest rates.
