The Fund invests at least 80% of its assets (defined as net assets plus any borrowing for investment purposes, if any) in tax-exempt municipal securities, the income from which is exempt from both federal and state income tax (80% investment policy). The Fund expects to invest up to 100% of its assets in tax-exempt municipal securities issued by Puerto Rico, Guam and the U.S. Virgin Islands. Municipal securities may be of any maturity, duration or credit rating including those rated below investment grade (commonly known as junk bonds). The Fund considers non-investment grade fixed income securities to be those that are rated lower than Baa3 by Moodys Investors Service (Moodys) or lower than BBB- by Standard and Poors Rating Group (S&P).