UNITED STATES
                        SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                             SCHEDULE 14A INFORMATION
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                       the Securities Exchange Act of 1934


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                PIONEER DIVERSIFIED HIGH INCOME FUND, INC. (HNW)
                     PIONEER FLOATING RATE FUND, INC. (PHD)
                      PIONEER HIGH INCOME FUND, INC. (PHT)
                 PIONEER MUNICIPAL HIGH INCOME FUND, INC. (MHI)
            PIONEER MUNICIPAL HIGH INCOME ADVANTAGE FUND, INC. (MAV)
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                (Name of Registrant(s) as Specified In Its Charter)

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                                      LOGO


                                                                August 18, 2021

               PIONEER DIVERSIFIED HIGH INCOME FUND, INC. (HNW)
                    PIONEER FLOATING RATE FUND, INC. (PHD)
                     PIONEER HIGH INCOME FUND, INC. (PHT)
                PIONEER MUNICIPAL HIGH INCOME FUND, INC. (MHI)
           PIONEER MUNICIPAL HIGH INCOME ADVANTAGE FUND, INC. (MAV)

DEAR FELLOW STOCKHOLDER:

We hope you and your family are safe and healthy during this unprecedented
time. As a stockholder in one or more of the above Pioneer Closed-End Funds
("Funds"), you recently received a proxy communication via email or a proxy
statement and proxy card(s) in the mail in connection with the Funds' Annual
Meeting of Stockholders scheduled to be held on September 15, 2021.

Stockholders of each Fund are being asked to consider and elect Directors of
the Fund, each to serve on the Fund's Board of Directors (the "Board") for a
three-year term or until a successor is elected. Each nominee is currently
serving on your Board and is seeking re-election. Each is highly qualified and
experienced to oversee each Fund's management and operations. Please refer to
the proxy statement for additional information regarding the nominees. If you
don't have your physical copy of the proxy statement, you can find it online
here: www.eproxyaccess.com/amundi2021

It is important that you exercise your right to vote. Please take a few minutes
to sign, date and mail the enclosed card in the prepaid envelope or follow the
instructions below to voted by telephone or internet

LOGO  Vote by Phone by calling 1-833-459-3559 and speaking with a proxy voting
      specialist today. Our representatives are available weekdays from 10
      a.m. to 11 p.m. Eastern time. You may also call the toll-free number on
      the enclosed card and follow the prompts.

LOGO  Vote by Internet by visiting the internet address on the enclosed card
      and following the instructions.

LOGO  Vote by Mail by completing, signing, and dating the enclosed card and
      returning it in the enclosed prepaid return envelope.

Our proxy solicitor, Di Costa Partners ("DCP"), may call you to answer any
question you may have regarding the proxy and to assist you in voting. You can
call DCP at 1-833-459-3559 during normal business hours, Monday - Friday, 10:00
a.m. - 11:00 p.m., Eastern if you have any questions regarding the proxy.

Thank you in advance for your vote,

LOGO

LISA M. JONES
PRESIDENT AND CHIEF EXECUTIVE OFFICER
PIONEER FUNDS

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