American Century Municipal Trust Statement of Additional Information (SAI) Supplement High-Yield Municipal Fund ¡ Long-Term Tax-Free Fund New York Tax-Free Fund ¡ Tax-Free Bond Fund Tax-Free Money Market Fund
Supplement dated October 1, 2010 ¡ SAI dated October 1, 2010

Effective November 1, 2010, the Tax-Free Bond Fund will be renamed the Intermediate-Term Tax-Free Bond Fund.

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