1
 
                                            VAN KAMPEN AMERICAN CAPITAL
 
                                   ---------------------------------------------
 
September 12, 1995
 
Dear Van Kampen American Capital Municipal Bond Fund Shareholder:
 
Early last month you were sent a Proxy Statement/Prospectus dated July 31, 1995
regarding your Fund's upcoming shareholder meeting. This letter amends that
Proxy Statement/Prospectus. At a recent meeting, the Board of Trustees of the
Van Kampen American Capital Municipal Bond Fund ("AC Fund") approved an
amendment to the AC Fund's Declaration of Trust which authorizes trustees of the
AC Fund to remove trustees with or without cause upon the act of two-thirds of
the trustees. The shareholder meeting of your Fund scheduled for September 15,
1995 will be adjourned until September 21, 1995 to allow you sufficient time to
consider this change, which is described in more detail below.
 
       The section of the Proxy Statement/Prospectus captioned
       "Description of Securities to be Issued -- Voting Rights of
       Shareholders" states the Declaration of Trust of the Van Kampen
       American Capital Municipal Income Fund ("VK Fund") and the AC Fund
       are substantially identical, except that the Declaration of Trust
       of the VK Fund permits the VK Board or shareholders to remove a
       trustee of the VK Fund with or without cause by the act of
       two-thirds of such trustees or shareholders, whereas the
       Declaration of Trust of the AC Fund permits (i) the removal of a
       trustee with cause by the act of two-thirds of the trustees and
       (ii) shareholders holding a majority of the shares of each series
       outstanding to remove a trustee with or without cause. The AC Fund
       Board of Trustees has amended the AC Fund Declaration of Trust to
       authorize the trustees of the AC Fund to remove trustees with or
       without cause upon the act of two-thirds of the trustees. The
       effect of this amendment is to substantially conform the
       provisions of the VK Fund and AC Fund Declarations of Trust
       relating to the removal of trustees.
 
       Also at the Board meeting, Linda Heagy was appointed to the Boards
       of Trustees of the AC Fund and the VK Fund and Richard Caruso was
       removed from the Boards of Trustees of the AC Fund and the VK
       Fund. Additional information regarding Linda Heagy's business
       experience has been added to each Fund's Statement of Additional
       Information.
 
IF YOU HAVE VOTED AND DO NOT WANT TO CHANGE YOUR VOTE, NO ACTION IS REQUIRED.
However, if you have not voted or would like to change your vote, we have
enclosed a new proxy card for your convenience. Please sign, date and return the
proxy card in the enclosed postage-paid envelope.
 
Should you need a Proxy Statement/Prospectus for review, please contact Van
Kampen American Capital Investor Services Department at 1-800-421-5666 between
the hours of 7:00 a.m. and 7:00 p.m. Central time. We appreciate your time and
careful consideration.
 
Van Kampen American Capital Municipal Bond Fund
Van Kampen American Capital Municipal Income Fund
 
                                                                             427
   2
 
                                            VAN KAMPEN AMERICAN CAPITAL
 
                                   ---------------------------------------------
 
September 12, 1995
 
Dear Van Kampen American Capital Insured Municipal Fund Shareholder:
 
Early last month you were sent a Proxy Statement/Prospectus dated July 31, 1995
regarding your Fund's upcoming shareholder meeting. This letter amends that
Proxy Statement/Prospectus. At a recent meeting, the Board of Trustees of the
Van Kampen American Capital Insured Municipal Fund ("AC Fund"), approved an
amendment to the AC Fund's Declaration of Trust which authorizes trustees of the
AC Fund to remove trustees with or without cause upon the act of two-thirds of
the trustees. The shareholder meeting of your Fund scheduled for September 15,
1995 will be adjourned until September 21, 1995 to allow you sufficient time to
consider this change, which is described in more detail below.
 
       The section of the Proxy Statement/Prospectus captioned
       "Description of Securities to be Issued -- Voting Rights of
       Shareholders" states the Declaration of Trust of the Van Kampen
       American Capital Insured Tax Free Income Fund ("VK Fund") and the
       AC Fund are substantially identical, except that the Declaration
       of Trust of the VK Fund permits the VK Board or shareholders to
       remove a trustee of the VK Fund with or without cause by the act
       of two-thirds of such trustees or shareholders, whereas the
       Declaration of Trust of the AC Fund permits (i) the removal of a
       trustee with cause by the act of two-thirds of the trustees and
       (ii) shareholders holding a majority of the shares of each series
       outstanding to remove a trustee with or without cause. The AC Fund
       Board of Trustees has amended the AC Fund Declaration of Trust to
       authorize the trustees of the AC Fund to remove trustees with or
       without cause upon the act of two-thirds of the trustees. The
       effect of this amendment is to substantially conform the
       provisions of the VK Fund and AC Fund Declarations of Trust
       relating to the removal of trustees.
 
       Also at the Board meeting, Linda Heagy was appointed to the Boards
       of Trustees of the AC Fund and the VK Fund and Richard Caruso was
       removed from the Boards of Trustees of the AC Fund and the VK
       Fund. Additional information regarding Linda Heagy's business
       experience has been added to each Fund's Statement of Additional
       Information.
 
IF YOU HAVE VOTED AND DO NOT WANT TO CHANGE YOUR VOTE, NO ACTION IS REQUIRED.
However, if you have not voted or would like to change your vote, we have
enclosed a new proxy card for your convenience. Please sign, date and return the
proxy card in the enclosed postage-paid envelope.
 
Should you need a Proxy Statement/Prospectus for review, please contact Van
Kampen American Capital Investor Services Department at 1-800-421-5666 between
the hours of 7:00 a.m. and 7:00 p.m. Central time. We appreciate your time and
careful consideration.
 
Van Kampen American Capital Insured Municipal Fund
Van Kampen American Capital Insured Tax Free Income Fund
 
                                                                             451