OREANDA-NEWS. Fitch Ratings has affirmed the 'AAA' ratings assigned to the auction market preferred shares (AMPS) issued by the following closed-end funds managed by Pioneer Investments Management (Pioneer):

--Pioneer Municipal High Income Trust (NYSE: MHI)
--Pioneer Municipal High Income Advantage Trust (NYSE: MAV)

A complete list of rated AMPS series follows at the end of this press release.

KEY RATING DRIVERS
The 'AAA' rating affirmations reflects:

--Sufficient asset coverage provided to the AMPS by the underlying portfolios of assets;
--The structural protections afforded by mandatory de-leveraging provisions in the event of asset coverage declines;
--The legal and regulatory parameters that govern the funds' operations;
--The capabilities of Pioneer as investment advisor.

LEVERAGE
As of Jan. 29, 2016, MHI's total assets were approximately $410 million and total leverage was approximately $101 million in Fitch-rated AMPS or 25% of total assets. MAV's total assets were approximately $453 million and total leverage was approximately $150 million in Fitch-rated AMPS, or 33% of total assets.

ASSET COVERAGE
At the time of the rating affirmations, the funds' asset coverage ratios, as calculated in accordance with the Fitch total and net overcollateralization tests (Fitch OC tests) per the 'AAA' rating guidelines outlined in Fitch's applicable criteria, were in excess of 100%, which is the minimum asset coverage amount deemed consistent with an 'AAA' rating. The funds' governing documents require that asset coverage for the AMPS, as calculated in accordance with the Fitch OC tests, be maintained in excess of 100%. Should the asset coverage decline below 100%, the governing documents require the funds to restore compliance.

The Fitch OC tests calculate standardized asset coverage by applying haircuts to portfolio holdings based on riskiness and diversification of the assets and measuring their ability to cover both on- and off-balance sheet liabilities at the stress level that corresponds to the assigned rating.

Additionally, as of the same date, the funds' asset coverage ratios for total outstanding AMPS, as calculated in accordance with Pioneer's interpretation of the Investment Company Act of 1940, were in excess of 200%, which is also a minimum asset coverage required by the funds' governing documents.

STRUCTURAL PROTECTIONS
Should the AMPS Fitch OC and asset coverage tests decline below their minimum threshold amounts (as tested weekly), the funds' managers are required to cure the breach by altering the composition of the portfolio toward assets with lower discount factors (for Fitch OC test breaches), or by reducing leverage in a sufficient amount (for both the Fitch OC test and 1940 asset coverage test breaches) within a pre-specified time period (a maximum of 40 business days).

FUNDS PROFILE

PIONEER MUNICIPAL HIGH INCOME TRUST (MHI)
MHI is a diversified closed-end management investment company, registered under the Investment Company Act of 1940, as amended, that commenced investment operations in July 2003. The fund seeks to provide a high level of current income exempt from regular federal income tax with a secondary investment objective of capital appreciation. The fund seeks to invest in assets consisting primarily of municipal securities, the interest on which is exempt from regular Federal income tax and preferred securities that are eligible to pay dividends which qualify for the long term capital gains rate for individual investors.

PIONEER MUNICIPAL HIGH INCOME ADVANTAGE TRUST (MAV)
MAV is a diversified closed-end management company, registered under the Investment Company Act of 1940, as amended, that commenced operations in October 2003. The fund seeks to provide a high level of current income exempt from regular federal income tax with a secondary investment objective of capital appreciation. The fund seeks to invest in assets consisting primarily of municipal securities, the interest on which is exempt from regular Federal income tax and preferred securities that are eligible to pay dividends which qualify for the long term capital gains rate for individual investors.

THE ADVISOR
Pioneer acts as the funds' investment advisor and is a wholly owned subsidiary of Pioneer Global Asset Management S.p.A., an investment management arm of UniCredit Banking Group. As of Dec. 31, 2015, Pioneer Global Asset Management S.p.A. had approximately $243 billion of assets under management, of which approximately $67 billion was managed in the U.S. A merger of Pioneer Investments and Santander Asset Management was announced in 2015 and is expected to be completed in 2016. Fitch expects the merger to have no impact on the ratings of the outstanding AMPS.

Fitch affirms the following ratings at 'AAA':

Pioneer Municipal High Income Trust (MHI):
--$50,000,000 of auction market preferred shares, series A, with a liquidation preference of $25,000 per share;
--$51,000,000 of auction market preferred shares, series B, with a liquidation preference of $25,000 per share.

Pioneer Municipal High Income Advantage Trust (MAV):
--$75,000,000 of auction market preferred shares, series A, with a liquidation preference of $25,000 per share;
--$75,000,000 of auction market preferred shares, series B, with a liquidation preference of $25,000 per share.