Muni national short portfolios invest in bonds issued by state and local governments to fund public projects. The income from these bonds is generally free from federal taxes and/or from state taxes in the issuing state. To lower risk, some of these portfolios spread their assets across many states and sectors. Other portfolios buy bonds from only one state in order to get the state-tax benefit. These portfolios have durations of less than 4.0 years (or average maturities of less than five years).