Pioneer Municipal High Income Trust is a closed ended fixed income mutual fund launched and managed by Pioneer Investment Management, Inc. It invests in the fixed income markets of the United States. The fund invests primarily in municipal bonds. The fund benchmarks the performance of its portfolio against the Barclays Municipal Bond Index and Barclays High Yield Municipal Bond Index. Pioneer Municipal High Income Trust was formed on March 13, 2003 and is domiciled in the United States.