Van Kampen High Yield Fund
-------------------------------------------------------------------------------

Van Kampen High Yield Fund's primary investment objective is to seek to provide
a high level of current income. As a secondary investment objective, the Fund
seeks capital appreciation. The Fund's investment adviser seeks to achieve the
Fund's investment objectives primarily through investment in a portfolio
of lower-grade domestic corporate debt securities.

Shares of the Fund have not been approved or disapproved by the Securities and
Exchange Commission (SEC) or any state regulator, and neither the SEC nor any
state regulator has passed upon the accuracy or adequacy of this Prospectus. Any
representation to the contrary is a criminal offense.

This Prospectus is dated JULY 30, 2004

CLASS A SHARES
CLASS B SHARES
CLASS C SHARES

[VAN KAMPEN INVESTMENTS LOGO]

Table of Contents

<Table>

Risk/Return Summary......................................... 3
Fees and Expenses of the Fund............................... 6
Investment Objectives, Strategies and Risks................. 7
Investment Advisory Services................................ 13
Purchase of Shares.......................................... 14
Redemption of Shares........................................ 21
Distributions from the Fund................................. 23
Shareholder Services........................................ 23
Federal Income Taxation..................................... 26
Financial Highlights........................................ 28
Appendix -- Description of Securities Ratings............... A-1
</Table>

No dealer, salesperson or any other person has been authorized to give any
information or to make any representations, other than those contained in this
Prospectus, in connection with the offer contained in this Prospectus and, if
given or made, such other information or representations must not be relied upon
as having been authorized by the Fund, the Fund's investment adviser or the
Fund's distributor. This Prospectus does not constitute an offer by the Fund or
by the Fund's distributor to sell or a solicitation of an offer to buy any of
the securities offered hereby in any jurisdiction to any person to whom it is
unlawful for the Fund to make such an offer in such jurisdiction.

Risk/Return Summary

-------------------------------------------------------------------------------

INVESTMENT OBJECTIVES

The Fund's primary investment objective is to seek to provide a high level of
current income. As a secondary investment objective, the Fund seeks capital
appreciation.

PRINCIPAL INVESTMENT STRATEGIES

Under normal market conditions, the Fund's investment adviser seeks to achieve
the Fund's investment objectives by investing primarily in a portfolio of lower-
grade domestic corporate debt securities. The Fund also may invest up to 35% of
its total assets in debt securities of similar quality issued by foreign
governments or foreign corporations. The Fund invests in a broad range of debt
securities represented by various companies and industries and traded on various
markets. The Fund buys and sells securities with a view to seeking a high level
of current income and capital appreciation over the long-term. Lower-grade
securities are commonly referred to as "junk bonds." The Fund's investments in
lower-grade securities involve greater risks as compared to higher-grade
securities. The Fund may purchase and sell securities on a when-issued or
delayed delivery basis. The Fund may purchase and sell certain derivative
instruments, such as options, futures contracts, options on futures contracts
and interest rate swaps or other interest rate-related transactions, for various
portfolio management purposes, including to earn income, to facilitate portfolio
management and to mitigate risks.

PRINCIPAL INVESTMENT RISKS

An investment in the Fund is subject to risks, and you could lose money on your
investment in the Fund. There can be no assurance that the Fund will achieve its
investment objectives.

CREDIT RISK. Credit risk refers to an issuer's ability to make timely payments
of interest and principal. The Fund invests primarily in securities with
lower-grade credit quality. Therefore, the Fund is subject to a higher level of
credit risk than a fund that invests solely in investment-grade securities. The
credit quality of "noninvestment-grade" securities is considered speculative by
recognized rating agencies with respect to the issuer's continuing ability to
pay interest and principal. Lower-grade securities may have less liquidity and a
higher incidence of default than higher-grade securities. The Fund may incur
higher expenses to protect the Fund's interest in such securities. The credit
risks and market prices of lower-grade securities generally are more sensitive
to negative issuer developments, such as reduced revenues or increased
expenditures, or adverse economic conditions, such as a recession, than are
higher-grade securities.

MARKET RISK. Market risk is the possibility that the market values of securities
owned by the Fund will decline. The prices of debt securities tend to fall as
interest rates rise, and such declines tend to be greater among debt securities
with longer maturities. The Fund has no policy limiting the maturities of its
investments. To the extent that the Fund invests in securities with longer
maturities, the Fund is subject to greater market risk than a fund investing
solely in shorter-term securities. Lower-grade securities may be more volatile
and decline more in price in response to negative issuer developments or general
economic news than higher-grade securities.

Market risk is often greater among certain types of debt securities, such as
zero coupon bonds or pay-in-kind securities. As interest rates change, these
securities often fluctuate more in price than traditional debt securities and
may subject the Fund to greater market risk than a fund that does not own these
types of securities.

When-issued and delayed delivery transactions are subject to changes in market
conditions from the time of the commitment until settlement. This may adversely
affect the prices or yields of the securities being purchased. The greater the
Fund's outstanding commitments for these securities, the greater the Fund's
exposure to market price fluctuations.

INCOME RISK. The income you receive from the Fund is based primarily on interest
rates and credit risk, which can vary widely over the short- and long-term. If
interest rates drop, your income from the Fund may drop as well.

CALL RISK. If interest rates fall, it is possible that issuers of debt
securities with high interest rates will prepay or "call" their securities
before their maturity dates. In this event, the proceeds from the called
securities would likely be reinvested by the Fund in

securities bearing the new, lower interest rates, resulting in a possible
decline in the Fund's income and distributions to shareholders.

FOREIGN RISKS. Because the Fund may own securities of foreign issuers, it may be
subject to risks not usually associated with owning securities of U.S. issuers.
These risks can include fluctuations in foreign currencies, foreign currency
exchange controls, political and economic instability, differences in financial
reporting, differences in securities regulation and trading and foreign taxation
issues.

RISKS OF USING DERIVATIVE INSTRUMENTS. In general terms, a derivative instrument
is one whose value depends on (or is derived from) the value of an underlying
asset, interest rate or index. Options, futures contracts, options on futures
contracts and interest rate swaps or other interest rate-related transactions
are examples of derivative instruments. Derivative instruments involve risks
different from direct investments in underlying securities. These risks include
imperfect correlation between the value of the instruments and the underlying
assets; risks of default by the other party to certain transactions; risks that
the transactions may result in losses that partially or completely offset gains
in portfolio positions; and risks that the transactions may not be liquid.

MANAGER RISK. As with any managed fund, the Fund's investment adviser may not be
successful in selecting the best-performing securities or investment techniques,
and the Fund's performance may lag behind that of similar funds.

INVESTOR PROFILE

In light of the Fund's investment objectives and strategies, the Fund may be
appropriate for investors who:

- Seek a high level of current income and, secondarily, capital appreciation

- Are willing to take on the substantially increased risks of lower-grade
securities

- Wish to add to their investment portfolio a fund that invests primarily in
lower-grade domestic corporate debt securities

An investment in the Fund is not a deposit of any bank or other insured
depository institution. An investment in the Fund is not insured or guaranteed
by the Federal Deposit Insurance Corporation or any other government agency.

An investment in the Fund may not be appropriate for all investors. The Fund is
not intended to be a complete investment program, and investors should consider
their long-term investment goals and financial needs when making an investment
decision about the Fund. An investment in the Fund is intended to be a long-
term investment, and the Fund should not be used as a trading vehicle.

ANNUAL PERFORMANCE

One way to measure the risks of investing in the Fund is to look at how its
performance has varied from year to year. The following chart shows the annual
returns of the Fund's Class A Shares over the ten calendar years prior to the
date of this Prospectus. Sales loads are not reflected in this chart. If these
sales loads had been included, the returns shown below would have been lower.
Remember that past performance of the Fund is not indicative of its future
performance.

[BAR GRAPH]

<Table>
<Caption>
ANNUAL RETURN
-------------

1994 -3.34
1995 17.52
1996 12.48
1997 10.97
1998 -1.45
1999 6.29
2000 -8.80
2001 -5.22
2002 -9.39
2003 24.55
</Table>

The Fund's return for the six-month period ended June 30, 2004 for Class A
Shares was 1.51%. As a result of market activity, current performance may vary
from the figures shown.

The annual returns of the Fund's Class B Shares and Class C Shares would be
substantially similar to those shown for the Class A Shares because all of the
Fund's shares are invested in the same portfolio of securities;

however, the actual annual returns of the Class B Shares and Class C Shares
would be lower than the annual returns shown for the Fund's Class A Shares
because of differences in the expenses borne by each class of shares.

During the ten-year period shown in the bar chart, the highest quarterly return
for Class A Shares was 7.95% (for the quarter ended June 30, 2003) and the
lowest quarterly return for Class A Shares was -8.36% (for the quarter ended
September 30, 1998).

COMPARATIVE PERFORMANCE

As a basis for evaluating the Fund's performance and risks, the table below
shows how the Fund's performance compares with the Credit Suisse First Boston
High Yield Index*, a broad-based market index that the Fund's investment adviser
believes is an appropriate benchmark for the Fund. The Fund's performance
figures include the maximum sales charges paid by investors. The index
performance figures do not include any commissions, sales charges or taxes that
would be paid by investors purchasing the securities represented by the index.
An investment cannot be made directly in an index.

In addition to before tax returns for each class of shares, the table shows
after tax returns for the Fund's Class A Shares in two ways: (i) after taxes on
distributions and (ii) after taxes on distributions and sale of Fund shares. The
after tax returns for the Fund's Class B Shares and Class C Shares will vary
from the Class A Shares' returns. After tax returns are calculated using the
historical highest individual federal marginal income tax rates during the
periods shown and do not reflect the impact of state and local taxes. Actual
after tax returns depend on an investor's tax situation and may differ from
those shown, and after tax returns are not relevant to investors who hold their
Fund shares through tax-deferred arrangements, such as 401(k) plans or
individual retirement accounts. An after tax return may be higher than the
before tax return due to an assumed benefit from any capital loss that would
have been realized had Fund shares been sold at the end of the relevant period.

Average annual total returns (before and after taxes) are shown for the periods
ended December 31, 2003 (the most recently completed calendar year prior to the
date of this Prospectus). Remember that past performance (before and after
taxes) of the Fund is not indicative of its future performance.

<Table>
<Caption>
AVERAGE ANNUAL
TOTAL RETURNS
FOR THE
PERIODS ENDED PAST PAST PAST
DECEMBER 31, 2003 1 YEAR 5 YEARS 10 YEARS
---------------------------------------------------------------

Van Kampen High Yield
Fund -- Class A Shares

Return Before Taxes 18.60% -0.26% 3.27%

Return After Taxes on
Distributions 15.98% -3.96% -0.42%

Return After Taxes on
Distribution and Sale of
Fund Shares 11.94% -2.48% 0.50%

Credit Suisse First Boston
High Yield Index 27.94% 6.44% 7.30%
................................................................
Van Kampen High Yield
Fund -- Class B Shares --
Return Before Taxes 19.76% -0.20% 3.29%**

Credit Suisse First Boston
High Yield Index 27.94% 6.44% 7.30%
................................................................
Van Kampen High Yield
Fund -- Class C Shares --
Return Before Taxes 22.81% -0.03% 2.97%

Credit Suisse First Boston
High Yield Index 27.94% 6.44% 7.30%
................................................................
</Table>

* The Credit Suisse First Boston High Yield Index is a broad-based, unmanaged
index that reflects the general performance of a wide range of selected bonds
within the public high-yield debt market.

** The "Past 10 Years" performance for Class B Shares reflects the conversion of
such shares into Class A Shares six years after the end of the calendar month
in which the shares were purchased. Class B Shares purchased on or after June
1, 1996 will convert to Class A Shares eight years after the end of the
calendar month in which the shares were purchased. See "Purchase of Shares."

The current yield for the thirty-day period ended March 31, 2004 is 5.93% for
Class A Shares, 5.43% for Class B Shares and 5.44% for Class C Shares. Investors
can obtain the current yield of the Fund for each class of shares by calling
(800) 847-2424 or by visiting our web site at www.vankampen.com.

Fees and Expenses
of the Fund

-------------------------------------------------------------------------------

This table describes the fees and expenses that you may pay if you buy and hold
shares of the Fund.

<Table>
<Caption>
CLASS A CLASS B CLASS C
SHARES SHARES SHARES
----------------------------------------------------------------

SHAREHOLDER FEES
(fees paid directly from your investment)
----------------------------------------------------------------
Maximum sales charge
(load) imposed on
purchases (as a
percentage of offering
price) 4.75%(1) None None
.................................................................
Maximum deferred sales
charge (load) (as a
percentage of the lesser
of original purchase
price or redemption
proceeds) None(2) 4.00%(3) 1.00%(4)
.................................................................
Maximum sales charge
(load) imposed on
reinvested dividends None None None
.................................................................
Redemption fee None None None
.................................................................
Exchange fee None None None
.................................................................

ANNUAL FUND OPERATING EXPENSES
(expenses that are deducted from Fund assets and are based on
expenses incurred during the Fund's fiscal year ended March 31,
2004)
----------------------------------------------------------------
Management fees(5) 0.75% 0.75% 0.75%
.................................................................
Distribution and/or
service (12b-1) fees(6) 0.25% 1.00% 1.00%
.................................................................
Other expenses(5) 0.29% 0.29% 0.29%
.................................................................
Total annual fund
operating expenses(5) 1.29% 2.04% 2.04%
.................................................................
</Table>

(1) Reduced for purchases of $100,000 and over. See "Purchase of Shares -- Class
A Shares."

(2) Investments of $1 million or more are not subject to any sales charge at the
time of purchase, but a deferred sales charge of 1.00% may be imposed on
certain redemptions made within one year of the purchase. See "Purchase of
Shares -- Class A Shares."
(3) The maximum deferred sales charge is 4.00% in the first year after purchase
and declines thereafter as follows:

Year 1-4.00%
Year 2-3.75%
Year 3-3.50%
Year 4-2.50%
Year 5-1.50%
Year 6-1.00%
After-None

See "Purchase of Shares -- Class B Shares."

(4) The maximum deferred sales charge is 1.00% in the first year after purchase
and 0.00% thereafter. See "Purchase of Shares -- Class C Shares."

(5) The Fund's investment adviser is currently waiving or reimbursing a portion
of the Fund's management fees or other expenses such that the actual total
annual fund operating expenses paid for the Fund's fiscal year ended March
31, 2004 were 1.19%, 1.94% and 1.94% for Class A Shares, Class B Shares and
Class C Shares, respectively. The fee waivers or expense reimbursements can
be terminated at any time.

(6) Class A Shares are subject to a combined annual distribution and service fee
of up to 0.25% of the average daily net assets attributable to such class of
shares. Class B Shares and Class C Shares are each subject to a combined
annual distribution and service fee of up to 1.00% of the average daily net
assets attributable to such class of shares. See "Purchase of Shares."

(7) While Class B Shares and Class C Shares do not have any front-end sales
charges, their higher ongoing annual expenses (due to higher 12b-1 and
service fees) mean that over time you could end up paying more for these
shares than if you were to pay front-end sales charges for Class A Shares.

Example:

The following example is intended to help you compare the cost of investing in
the Fund with the costs of investing in other mutual funds.

The example assumes that you invest $10,000 in the Fund for the time periods
indicated and then redeem all of your shares at the end of those periods. The
example also assumes that your investment has a 5% return each year and that the
Fund's operating expenses remain the same each year (except for the ten-year
amounts for Class B Shares which reflect the conversion of Class B Shares to
Class A Shares eight years after the end of the calendar month in which the
shares were purchased). Although your actual costs may be higher or lower, based
on these assumptions your costs would be:

<Table>
<Caption>
ONE THREE FIVE TEN
YEAR YEARS YEARS YEARS
---------------------------------------------------------------------

Class A Shares $600 $ 865 $1,149 $1,958
......................................................................
Class B Shares $607 $ 990 $1,248 $2,176*
......................................................................
Class C Shares $307 $ 640 $1,098 $2,369
......................................................................
</Table>

You would pay the following expenses if you did not redeem your shares:

<Table>
<Caption>
ONE THREE FIVE TEN
YEAR YEARS YEARS YEARS
---------------------------------------------------------------------

Class A Shares $600 $ 865 $1,149 $1,958
......................................................................
Class B Shares $207 $ 640 $1,098 $2,176*
......................................................................
Class C Shares $207 $ 640 $1,098 $2,369
......................................................................
</Table>

* Based on conversion to Class A Shares eight years after the end of the
calendar month in which the shares were purchased.

Investment Objectives,
Strategies and Risks

-------------------------------------------------------------------------------

INVESTMENT OBJECTIVES

The Fund's primary investment objective is to seek to provide a high level of
current income. As a secondary investment objective, the Fund seeks capital
appreciation. The Fund's investment objectives are fundamental policies and may
not be changed without shareholder approval of a majority of the Fund's
outstanding voting securities, as defined in the Investment Company Act of 1940,
as amended (the "1940 Act"). There are risks inherent in all investments in
securities; accordingly, there can be no assurance that the Fund will achieve
its investment objectives.

INVESTMENT STRATEGIES AND RISKS

Under normal market conditions, the Fund's investment adviser seeks to achieve
the Fund's investment objectives by investing primarily in a portfolio of lower-
grade domestic corporate debt securities. The Fund also may invest up to 35% of
its total assets in debt securities of similar quality issued by foreign
governments and foreign corporations. Under normal market conditions, the Fund
invests primarily in securities rated at the time of purchase BB or lower by
Standard & Poor's ("S&P") or rated Ba or lower by Moody's Investors Service,
Inc. ("Moody's") or comparably rated short-term securities and unrated
securities determined by the Fund's investment adviser to be of comparable
quality at the time of purchase. With respect to such investments, the Fund has
not established any limit on the percentage of its portfolio which may be
invested in securities in any one rating category. Securities rated BB or lower
by S&P or rated Ba or lower by Moody's or comparably rated short-term securities
and unrated securities of comparable quality are regarded as below investment
grade and are commonly referred to as "junk bonds" and involve special risks as
compared to investments in higher-grade securities. See "Risks of Investing in
Lower-Grade Securities" below.

Under normal market conditions, the Fund invests at least 80% of its net assets
(plus any borrowings for investment purposes) in securities regarded as below
investment grade at the time of investment. The Fund's policy in the foregoing
sentence may be changed by the Fund's Board of Trustees, but no change is
anticipated; if the Fund's policy in the foregoing sentence changes, the Fund
will notify shareholders at least 60 days prior to implementation of the change
and shareholders should consider whether the Fund remains an appropriate
investment in light of the changes.

UNDERSTANDING

QUALITY RATINGS

Debt securities ratings are based on the issuer's ability to pay interest
and repay the principal. Debt securities with ratings above the bold line
in the table are considered "investment-grade," while those with ratings
below the bold line are regarded as "noninvestment-grade," or "junk
bonds." A detailed explanation of these and other ratings can be found in
the appendix to this Prospectus.

<Table>
<Caption>
S&P MOODY'S MEANING
------------------------------------------------------

AAA Aaa Highest quality
.......................................................
AA Aa High quality
.......................................................
A A Above-average quality
.......................................................
BBB Baa Average quality
------------------------------------------------------
BB Ba Below-average quality
.......................................................
B B Marginal quality
.......................................................
CCC Caa Poor quality
.......................................................
CC Ca Highly speculative
.......................................................
C C Lowest quality
.......................................................
D -- In default
.......................................................
</Table>

The Fund invests in a broad range of debt securities represented by various
companies and industries and traded in various markets. The Fund buys and sells
securities with a view to seeking a high level of current income and capital
appreciation over the long-term. The higher yields for current income and the
potential for capital appreciation sought by the Fund are generally obtainable
from securities in the lower-grade credit quality range. Such securities tend to
offer higher yields than higher-grade securities with the same maturities
because the historical conditions of the issuers of such securities may not have
been as strong as those of other issuers. These securities may be issued in
connection with corporate restructurings such as leveraged buyouts, mergers,
acquisitions, debt recapitalization or similar events. These securities are
often issued by less creditworthy companies or companies with substantial debt
and may include financially troubled companies or companies in default or in
restructuring. Such securities often are subordinated to the prior claims of
banks and other senior lenders. Lower-grade securities are regarded by the
rating agencies as predominantly speculative with respect to the issuer's
continuing ability to meet principal and interest payments. The ratings of S&P
and Moody's represent their opinions of the quality of the debt securities they
undertake to rate, but not the market risk of such securities. It should be
emphasized however, that ratings are general and are not absolute standards of
quality.

The Fund's investment adviser seeks to minimize the risks involved in investing
in lower-grade securities through diversification, careful investment analysis
and attention to current developments and trends in the economy and financial
and credit markets. In purchasing and selling securities, the Fund's investment
adviser evaluates the issuers of such securities based on a number of factors,
including but not limited to the issuers's financial resources, its sensitivity
to changing economic conditions and trends, its revenues or earnings potential,
its operating history, its current borrowing requirements and debt maturities,
the quality of its management, regulatory matters and its potential for capital
appreciation. The Fund's investment adviser may consider the ratings from S&P
and Moody's in evaluating securities but it does not rely primarily on such
ratings. The investment adviser continuously monitors the issuers of debt
securities held by the Fund.

The Fund may invest in preferred stocks, convertible securities, zero coupon
securities and payment-in-kind securities. The Fund also may invest up to 5% of
its assets in warrants and common stocks. For more information on these types of
investments, see "Investment Objectives, Policies and Risks" in the Fund's
Statement of Additional Information. The Fund's Statement of Additional
Information may be obtained by investors free of charge as described on the back
cover of this prospectus.

RISKS OF INVESTING IN
LOWER-GRADE SECURITIES

Securities that are in the lower-grade categories generally offer higher yields
than are offered by higher-grade securities of similar maturities, but they also
generally involve greater risks, such as greater credit risk, greater market
risk and volatility, greater liquidity concerns and potentially greater manager
risk. Investors should carefully consider the risks of owning shares of a fund
which invests in lower-grade securities before investing in the Fund.

Credit risk relates to an issuer's ability to make timely payment of interest
and principal when due. Lower-grade securities are considered more susceptible
to nonpayment of interest and principal or default than higher-grade securities.
Increases in interest rates or changes in the economy may significantly affect
the ability of issuers of lower-grade debt securities to pay interest and to
repay principal, to meet projected financial goals or to obtain additional
financing. In the event that an issuer of securities held by the Fund
experiences difficulties in the timely payment of principal and interest and
such issuer seeks to restructure the terms of its borrowings, the Fund may incur
additional expenses and may determine to invest additional assets with respect
to such issuer or the project or projects to which the Fund's securities relate.
Further, the Fund may incur additional expenses to the extent that it is
required to seek recovery upon a default in the payment of interest or the
repayment of principal on its portfolio holdings, and the Fund may be unable to
obtain full recovery on such amounts.

Market risk relates to changes in market value of a security that occur as a
result of variation in the level of prevailing interest rates and yield
relationships in the debt securities market and as a result of real or perceived
changes in credit risk. The value of the Fund's

investments can be expected to fluctuate over time. When interest rates decline,
the value of a portfolio invested in debt securities generally can be expected
to rise. Conversely, when interest rates rise, the value of a portfolio invested
in debt securities generally can be expected to decline. Debt securities with
longer maturities, which may have higher yields, may increase or decrease in
value more than debt securities with shorter maturities. However, the secondary
market prices of lower-grade securities generally are less sensitive to changes
in interest rates and are more sensitive to general adverse economic changes or
specific developments with respect to the particular issuers than are the
secondary market prices of higher-grade securities. A significant increase in
interest rates or a general economic downturn could severely disrupt the market
for lower-grade securities and adversely affect the market value of such
securities. Such events also could lead to a higher incidence of default by
issuers of lower-grade securities as compared with higher-grade securities. In
addition, changes in credit risks, interest rates, the credit markets or periods
of general economic uncertainty can be expected to result in increased
volatility in the market price of the lower-grade securities in the Fund and
thus in the net asset value of the Fund. Adverse publicity and investor
perceptions, whether or not based on rational analysis, may affect the value,
volatility and liquidity of lower-grade securities.

The markets for lower-grade securities may be less liquid than the markets for
higher-grade securities. Liquidity relates to the ability of a fund to sell a
security in a timely manner at a price which reflects the value of that
security. To the extent that there is no established retail market for some of
the lower-grade securities in which the Fund may invest, trading in such
securities may be relatively inactive. Prices of lower-grade securities may
decline rapidly in the event a significant number of holders decide to sell.
Changes in expectations regarding an individual issuer of lower-grade securities
generally could reduce market liquidity for such securities and make their sale
by the Fund more difficult, at least in the absence of price concessions. The
effects of adverse publicity and investor perceptions may be more pronounced for
securities for which no established retail market exists as compared with the
effects on securities for which such a market does exist. An economic downturn
or an increase in interest rates could severely disrupt the market for such
securities and adversely affect the value of outstanding securities or the
ability of the issuers to repay principal and interest. Further, the Fund may
have more difficulty selling such securities in a timely manner and at their
stated value than would be the case for securities for which an established
retail market does exist.

During periods of reduced market liquidity or in the absence of readily
available market quotations for lower-grade securities held in the Fund's
portfolio, the ability of the Fund to value the Fund's securities becomes more
difficult and the judgment of the Fund may play a greater role in the valuation
of the Fund's securities due to the reduced availability of reliable objective
data.

The Fund may invest in securities not producing immediate cash income, including
securities in default, zero coupon securities or pay-in-kind securities. Prices
on non-cash-paying instruments may be more sensitive to changes in the issuer's
financial condition, fluctuation in interest rates and market demand/supply
imbalances than cash-paying securities with similar credit ratings, and thus may
be more speculative. Special tax considerations are associated with investing in
certain lower-grade securities, such as zero coupon or pay-in-kind securities.
See "Federal Income Taxation" below. The Fund's investment adviser will weigh
these concerns against the expected total returns from such instruments.

The Fund's investments in lower-grade securities may include securities rated D
by S&P or C by Moody's (the lowest-grade assigned) and unrated securities of
comparable quality. Securities assigned such ratings include those of companies
that are in default or are in bankruptcy or reorganization. Securities of such
companies are regarded by the rating agencies as having extremely poor prospects
of ever attaining any real investment standing and are usually available at deep
discounts from the face values of the instruments. A security purchased at a
deep discount may currently pay a very high effective yield. In addition, if the
financial condition of the issuer improves, the underlying value of the security
may increase, resulting in capital appreciation. If the company defaults on its
obligations or remains in default, or if the plan of reorganization does not
provide sufficient payments for debtholders, the deep discount securities may
stop generating income and lose value or become worthless.

The Fund's investment adviser will balance the benefits of deep discount
securities with their risks. While a diversified portfolio may reduce the
overall impact of a deep discount security that is in default or loses its
value, the risk cannot be eliminated.

Many lower-grade debt securities are not listed for trading on any national
securities exchange, and issuers of lower-grade debt securities may choose not
to have a rating assigned to their obligations by any nationally recognized
statistical rating organization. As a result, the Fund's portfolio may consist
of a higher portion of unlisted or unrated securities as compared with an
investment company that invests solely in higher-grade securities. Unrated
securities are usually not as attractive to as many buyers as are rated
securities, a factor which may make unrated securities less marketable. These
factors may have the effect of limiting the availability of the securities for
purchase by the Fund and may also limit the ability of the Fund to sell such
securities at their fair value either to meet redemption requests or in response
to changes in the economy or the financial markets. Further, to the extent the
Fund owns or may acquire illiquid or restricted lower-grade securities, these
securities may involve special registration responsibilities, liabilities and
costs, and liquidity and valuation difficulties.

The Fund will rely on its investment adviser's judgment, analysis and experience
in evaluating the creditworthiness of an issuer. The amount of available
information about the financial condition of certain lower-grade issuers may be
less extensive than other issuers. In its analysis, the Fund's investment
adviser may consider the credit ratings of recognized rating organizations in
evaluating securities although the investment adviser does not rely primarily on
these ratings. Credit ratings of securities rating organizations evaluate only
the safety of principal and interest payments, not the market risk. In addition,
ratings are general and not absolute standards of quality, and credit ratings
are subject to the risk that the creditworthiness of an issuer may change and
the rating agencies may fail to change such ratings in a timely fashion. A
rating downgrade does not require the Fund to dispose of a security. The Fund's
investment adviser continuously monitors the issuers of securities held in the
Fund. Additionally, since most foreign debt securities are not rated, the Fund
will invest in such securities based on the analysis of the Fund's investment
adviser without any guidance from published ratings. Because of the number of
investment considerations involved in investing in lower-grade securities and
foreign debt securities, achievement of the Fund's investment objectives may be
more dependent upon the credit analysis of the Fund's investment adviser than is
the case with investing in higher-grade securities.

New or proposed laws may have an impact on the market for lower-grade
securities. The Fund's investment adviser is unable at this time to predict what
effect, if any, legislation may have on the market for lower-grade securities.

The table below sets forth the percentages of the Fund's assets during the
fiscal period ended March 31, 2004 invested in the various S&P and Moody's
rating categories and in unrated securities determined by the Fund's investment
adviser to be of comparable quality. The percentages are based on the
dollar-weighted average of credit ratings of all securities held by the Fund
during the 2004 fiscal year computed on a monthly basis.

<Table>
<Caption>
FISCAL YEAR ENDED MARCH 31, 2004
UNRATED SECURITIES OF
RATED SECURITIES COMPARABLE QUALITY
(AS A PERCENTAGE OF (AS A PERCENTAGE OF
RATING CATEGORY PORTFOLIO VALUE) PORTFOLIO VALUE)
--------------------------------------------------------------------

AAA/Aaa 0.00% 0.00%
.....................................................................
AA/Aa 0.00% 0.00%
.....................................................................
A/A 0.00% 0.00%
.....................................................................
BBB/Baa 5.70% 0.00%
.....................................................................
BB/Ba 33.73% 0.03%
.....................................................................
B/B 47.93% 1.13%
.....................................................................
CCC/Caa 9.78% 0.44%
.....................................................................
CC/Ca 0.30% 0.00%
.....................................................................
C/C 0.57% 0.04%
.....................................................................
D 0.00% 0.35%
.....................................................................
Percentage of
Rated and
Unrated
Securities 98.01% 1.99%
.....................................................................
</Table>

The percentage of the Fund's assets invested in securities of various grades may
vary from time to time from those listed above.

RISKS OF INVESTING IN
SECURITIES OF FOREIGN ISSUERS

The Fund may invest up to 35% of its total assets in debt securities of similar
quality as the securities described above issued by foreign governments and
foreign corporations. Securities of foreign issuers may be denominated in U.S.
dollars or in currencies other than U.S. dollars.

Investments in securities of foreign issuers present certain risks not
ordinarily associated with investments in securities of U.S. issuers. These
risks include fluctuations in foreign currency exchange rates, political,
economic or legal developments (including war or other instability,
expropriation of assets, nationalization and confiscatory taxation), the
imposition of foreign exchange limitations (including currency blockage),
withholding taxes on income or capital transactions or other restrictions,
higher transaction costs (including higher brokerage, custodial and settlement
costs and currency conversion costs) and possible difficulty in enforcing
contractual obligations or taking judicial action. Securities of foreign issuers
may not be as liquid and may be more volatile than comparable securities of
domestic issuers.

In addition, there often is less publicly available information about many
foreign issuers, and issuers of foreign securities are subject to different,
often less comprehensive, auditing, accounting and financial reporting
disclosure requirements than domestic issuers. There is generally less
government regulation of exchanges, brokers and listed companies abroad than in
the United States and, with respect to certain foreign countries, there is a
possibility of expropriation or confiscatory taxation, or diplomatic
developments which could affect investment in those countries. Because there is
usually less supervision and governmental regulation of foreign exchanges,
brokers and dealers than there is in the United States, the Fund may experience
settlement difficulties or delays not usually encountered in the United States.

Delays in making trades in securities of foreign issuers relating to volume
constraints, limitations or restrictions, clearance or settlement procedures, or
otherwise could impact yields and result in temporary periods when assets of the
Fund are not fully invested or attractive investment opportunities are foregone.

The Fund may invest in securities of issuers determined by the investment
adviser to be in developing or emerging market countries. Investments in
securities of issuers in developing or emerging market countries are subject to
greater risks than investments in securities of developed countries since
emerging market countries tend to have economic structures that are less diverse
and mature and political systems that are less stable than developed countries.

In addition to the increased risks of investing in securities of foreign
issuers, there are often increased transaction costs associated with investing
in securities of foreign issuers, including the costs incurred in connection
with converting currencies, higher foreign brokerage or dealer costs and higher
settlement costs or custodial costs.

Since the Fund may invest in securities denominated or quoted in currencies
other than the U.S. dollar, the Fund will be affected by changes in foreign
currency exchange rates (and exchange control regulations) which affect the
value of investments in the Fund and the accrued income and appreciation or
depreciation of the investments. Changes in foreign currency exchange rates
relative to the U.S. dollar will affect the U.S. dollar value of the Fund's
assets denominated in that currency and the Fund's return on such assets as well
as any temporary uninvested reserves in bank deposits in foreign currencies. In
addition, the Fund will incur costs in connection with conversions between
various currencies.

The Fund may invest in securities of foreign issuers in the form of depositary
receipts. Depositary receipts involve substantially identical risks to those
associated with direct investment in securities of foreign issuers. In addition,
the underlying issuers of certain depositary receipts, particularly unsponsored
or unregistered depositary receipts, are under no obligation to distribute
shareholder communications to the holders of such receipts, or to pass through
to them any voting rights with respect to the deposited securities.

STRATEGIC TRANSACTIONS

The Fund may, but is not required to, use various investment strategic
transactions described below to earn income, to facilitate portfolio management
and to mitigate risks. Although the Fund's investment adviser seeks to use these
transactions to achieve the Fund's

investment objectives, no assurance can be given that the use of these
transactions will achieve this result.

The Fund may purchase and sell derivative instruments such as exchange-listed
and over-the-counter put and call options on securities, financial futures
contracts, equity, fixed-income and interest rate indices, and other financial
instruments, purchase and sell financial futures contracts and options on
futures contracts, enter into various interest rate transactions such as swaps,
caps, floors or collars, and enter into various currency transactions such as
currency forward contracts, currency futures contracts, currency swaps or
options on currency or currency futures contracts. Collectively, all of the
above are referred to as "Strategic Transactions." The Fund generally seeks to
use Strategic Transactions as a portfolio management or hedging technique to
seek to protect against possible adverse changes in the market value of
securities held in or to be purchased for the Fund's portfolio, protect the
Fund's unrealized gains, facilitate the sale of securities for investment
purposes, manage the effective interest rate exposure of the Fund, protect
against changes in currency exchange rates, manage the effective maturity or
duration of the Fund's portfolio, or establish positions in the derivatives
markets as a temporary substitute for purchasing or selling particular
securities. The Fund may sell options on securities it owns or has the right to
acquire without additional payments in an amount up to 25% of the Fund's total
assets for non-hedging purposes.

Strategic Transactions have risks including the imperfect correlation between
the value of such instruments and the underlying assets, the possible default of
the other party to the transaction or illiquidity of the derivative instruments.
Furthermore, the ability to successfully use Strategic Transactions depends on
the ability of the Fund's investment adviser to predict pertinent market
movements, which cannot be assured. Thus, the use of Strategic Transactions may
result in losses greater than if they had not been used, may require the Fund to
sell or purchase portfolio securities at inopportune times or for prices other
than current market values, may limit the amount of appreciation the Fund can
otherwise realize on an investment, or may cause the Fund to hold a security
that it might otherwise sell. The use of currency transactions can result in the
Fund incurring losses as a result of the imposition of exchange controls,
suspension of settlements or the inability to deliver or receive a specified
currency. In addition, amounts paid by the Fund as premiums and cash or other
assets held in margin accounts with respect to Strategic Transactions are not
otherwise available to the Fund for investment purposes.

A more complete discussion of Strategic Transactions and their risks is
contained in the Fund's Statement of Additional Information. The Statement of
Additional Information can be obtained by investors free of charge as described
on the back cover of this Prospectus.

OTHER INVESTMENTS AND RISK FACTORS

WHEN-ISSUED AND DELAYED DELIVERY. The Fund may purchase and sell securities on a
"when-issued" and "delayed delivery" basis whereby the Fund buys or sells a
security with payment and delivery taking place in the future. The payment
obligation and the interest rate are fixed at the time the Fund enters into the
commitment. No income accrues on such securities until the Fund actually takes
delivery of such securities. These transactions are subject to market
fluctuation; the value of the securities at delivery may be more or less than
their purchase price. The yields generally available on comparable securities
when delivery occurs may be higher or lower than yields on the securities
obtained pursuant to such transactions. Because the Fund relies on the buyer or
seller to consummate the transaction, failure by the other party to complete the
transaction may result in the Fund missing the opportunity of obtaining a price
or yield considered to be advantageous. The Fund will engage in when-issued and
delayed delivery transactions for the purpose of acquiring securities consistent
with the Fund's investment objectives and policies and not for the purpose of
investment leverage.

OTHER PRACTICES. For cash management purposes, the Fund may engage in repurchase
agreements with broker-dealers, banks and other financial institutions to earn a
return on temporarily available cash. Such transactions are subject to the risk
of default by the other party.

The Fund may invest up to 15% of its net assets in illiquid securities and
certain restricted securities. Such securities may be difficult or impossible to
sell at the time and the price that the Fund would like. Thus, the Fund may have
to sell such securities at a lower price,

sell other securities instead to obtain cash or forego other investment
opportunities.

The Fund may lend its portfolio securities in an amount up to 25% of its net
assets to broker-dealers, banks or other institutional borrowers of securities.
Such loans must be callable at any time and the borrower at all times during the
loan must maintain cash and/or U.S. government securities as collateral equal in
value to at least 100% of the value of the securities loaned (including accrued
interest). During the time portfolio securities are on loan, the Fund receives
any dividends or interest paid on such securities and receives the interest
earned on collateral which is invested in short-term investments and receives
the proceeds from such investment or receives an agreed-upon amount of interest
income from the borrower who has delivered the collateral. As with any
extensions of credit there are risks of delay in recovery and in some cases even
loss of rights in the collateral should the borrower of the securities fail
financially.

Further information about these types of investments and other investment
practices that may be used by the Fund is contained in the Fund's Statement of
Additional Information.

The Fund may sell securities without regard to the length of time they have been
held to take advantage of new investment opportunities, or when the Fund's
investment adviser believes the potential for income or capital appreciation has
lessened, or for other reasons. The Fund's portfolio turnover rate may vary from
year to year. A high portfolio turnover rate (100% or more) increases a fund's
transaction costs (including brokerage commissions or dealer costs), which would
adversely impact a fund's performance. Higher portfolio turnover may result in
the realization of more short-term capital gains than if a fund had lower
portfolio turnover. The turnover rate will not be a limiting factor, however, if
the Fund's investment adviser considers portfolio changes appropriate. The
Fund's portfolio turnover rate is reported in the section entitled "Financial
Highlights."

TEMPORARY DEFENSIVE STRATEGY. When market conditions dictate a more defensive
investment strategy, the Fund may, on a temporary basis, hold cash or invest a
portion or all of its assets in cash, higher-grade debt securities, securities
issued or guaranteed by the U.S. government, its agencies or instrumentalities
and money market instruments. Under normal market conditions, the potential for
current income or capital appreciation on these securities will tend to be lower
than the potential for current income or capital appreciation on other
securities that may be owned by the Fund. In taking such a defensive position,
the Fund would temporarily not be pursuing and may not achieve its investment
objectives.

Investment Advisory Services

-------------------------------------------------------------------------------

THE ADVISER. Van Kampen Asset Management is the Fund's investment adviser (the
"Adviser" or "Asset Management"). The Adviser is a wholly owned subsidiary of
Van Kampen Investments Inc. ("Van Kampen Investments"). Van Kampen Investments
is a diversified asset management company that administers more than three
million retail investor accounts, has extensive capabilities for managing
institutional portfolios and has more than $88 billion under management or
supervision as of June 30, 2004. Van Kampen Investments has more than 40
open-end funds, more than 30 closed-end funds and more than 2,700 unit
investment trusts that are distributed by authorized dealers nationwide. Van
Kampen Funds Inc., the distributor of the Fund (the "Distributor") and the
sponsor of the funds mentioned above, is also a wholly owned subsidiary of Van
Kampen Investments. Van Kampen Investments is an indirect wholly owned
subsidiary of Morgan Stanley, a preeminent global financial services firm that
maintains leading market positions in each of its three primary businesses:
securities, asset management and credit services. Morgan Stanley is a full
service securities firm engaged in securities trading and brokerage activities,
investment banking, research and analysis, financing and financial advisory
services. The Adviser's principal office is located at 1221 Avenue of the
Americas, New York, New York 10020.

ADVISORY AGREEMENT. The Fund retains the Adviser to manage the investment of its
assets and to place orders for the purchase and sale of its portfolio
securities. Under an investment advisory agreement

between the Adviser and the Fund (the "Advisory Agreement"), the Fund pays the
Adviser a monthly fee computed based upon an annual rate applied to the average
daily net assets of the Fund as follows:

<Table>
<Caption>
AVERAGE DAILY NET ASSETS % PER ANNUM
--------------------------------------------------

First $500 million 0.75%
...................................................
Over $500 million 0.65%
...................................................
</Table>

Applying this fee schedule, the effective advisory fee rate was 0.75% (before
fee waivers; and 0.65% after fee waivers) of the Fund's average daily net assets
for the Fund's fiscal year ended March 31, 2004. The Fund's average daily net
assets are determine by taking the average of all of the determinations of the
net assets during a given calendar month. Such fee is payable for each calendar
month as soon as practicable after the end of that month.

The Adviser furnishes offices, necessary facilities and equipment, and provides
administrative services to the Fund. The Fund pays all charges and expenses of
its day-to-day operations, including service fees, distribution fees, custodian
fees, legal and independent accountant fees, the costs of reports and proxies to
shareholders, compensation of trustees of the Fund (other than those who are
affiliated persons of the Adviser, Distributor or Van Kampen Investments) and
all other ordinary business expenses not specifically assumed by the Adviser.

From time to time, the Adviser or the Distributor may voluntarily undertake to
reduce the Fund's expenses by reducing the fees payable to them or by reducing
other expenses of the Fund in accordance with such limitations as the Adviser or
Distributor may establish.

PORTFOLIO MANAGEMENT. The Fund is managed by the Adviser's Taxable Fixed Income
team. The team is made up of established investment professionals. Current
members of the team include Sheila Finnerty, a Managing Director of the Adviser,
Gordon Loery, an Executive Director of the Adviser, and Joshua Givelber and Chad
Liu, Vice Presidents of the Adviser. The composition of the team may change
without notice from time to time.

Purchase of Shares

-------------------------------------------------------------------------------

GENERAL

This Prospectus offers three classes of shares of the Fund, designated as Class
A Shares, Class B Shares and Class C Shares. Other classes of shares of the Fund
may be offered through one or more separate prospectuses of the Fund. By
offering multiple classes of shares, the Fund permits each investor to choose
the class of shares that is most beneficial given the type of investor, the
amount to be invested and the length of time the investor expects to hold the
shares. As described more fully below, each class of shares offers a distinct
structure of sales charges, distribution and service fees and other features
that are designed to address a variety of needs.

Each class of shares of the Fund represents an interest in the same portfolio of
investments of the Fund and has the same rights except that (i) Class A Shares
generally bear the sales charge expenses at the time of purchase while Class B
Shares and Class C Shares generally bear the sales charge expenses at the time
of redemption and any expenses (including higher distribution fees and transfer
agency costs) resulting from such deferred sales charge arrangement, (ii) each
class of shares has exclusive voting rights with respect to approvals of the
Rule 12b-1 distribution plan and the service plan (each as described below)
under which the class's distribution fee and/or the service fee is paid, (iii)
each class of shares has different exchange privileges, (iv) certain classes of
shares are subject to a conversion feature and (v) certain classes of shares
have different shareholder service options available.

PRICING FUND SHARES

The offering price of the Fund's shares is based upon the Fund's net asset value
per share (plus sales charges, where applicable). The net asset values per share
of the Class A Shares, Class B Shares and Class C Shares are generally expected
to be substantially the same. The differences among the classes' per share net
asset values reflect the daily expense accruals of the higher distribution fees
and transfer agency costs applicable to the Class B Shares and Class C Shares
and the differential in the dividends that may be paid on each class of shares.

The net asset value per share for each class of shares of the Fund is determined
once daily as of the close of trading on the New York Stock Exchange (the
"Exchange") (currently 4:00 p.m., New York time) each day the Exchange is open
for trading except on any day on which no purchase or redemption orders are
received or there is not a sufficient degree of trading in the Fund's portfolio
securities such that the Fund's net asset value per share might be materially
affected. The Fund's Board of Trustees reserves the right to calculate the net
asset value per share and adjust the offering price more frequently than once
daily if deemed desirable. Net asset value per share for each class is
determined by dividing the value of the Fund's portfolio securities, cash and
other assets (including accrued interest) attributable to such class, less all
liabilities (including accrued expenses) attributable to such class, by the
total number of shares of the class outstanding. Portfolio securities are valued
by using market quotations, prices provided by market makers or estimates of
market values obtained from yield data relating to instruments or securities
with similar characteristics in accordance with procedures established by the
Fund's Board of Trustees. Securities for which market quotations are not readily
available and any other assets are valued at their fair value as determined in
good faith by the Adviser in accordance with procedures established by the
Fund's Board of Trustees. Securities with remaining maturities of 60 days or
less are valued at amortized cost, which approximates market value. See the
financial statements and notes thereto in the Fund's Statement of Additional
Information.

DISTRIBUTION PLAN AND SERVICE PLAN

The Fund has adopted a distribution plan (the "Distribution Plan") with respect
to each of its Class A Shares, Class B Shares and Class C Shares pursuant to
Rule 12b-1 under the 1940 Act. The Fund also has adopted a service plan (the
"Service Plan") with respect to each such class of its shares. Under the
Distribution Plan and the Service Plan, the Fund pays distribution fees in
connection with the sale and distribution of its shares and service fees in
connection with the provision of ongoing services to shareholders of each such
class and the maintenance of shareholder accounts.

The amount of distribution fees and service fees varies among the classes
offered by the Fund. Because these fees are paid out of the Fund's assets on an
ongoing basis, these fees will increase the cost of your investment in the Fund.
By purchasing a class of shares subject to higher distribution fees and service
fees, you may pay more over time than on a class of shares with other types of
sales charge arrangements. Long-term shareholders may pay more than the economic
equivalent of the maximum front-end sales charges permitted by the rules of the
NASD. The net income attributable to a class of shares will be reduced by the
amount of the distribution fees and service fees and other expenses of the Fund
associated with that class of shares.

To assist investors in comparing classes of shares, the tables under the
Prospectus heading "Fees and Expenses of the Fund" provide a summary of sales
charges and expenses and an example of the sales charges and expenses of the
Fund applicable to each class of shares offered herein.

HOW TO BUY SHARES

The shares are offered on a continuous basis through the Distributor as
principal underwriter, which is located at 1221 Avenue of the Americas, New
York, New York 10020. Shares may be purchased through members of the NASD who
are acting as securities dealers ("dealers") and NASD members or eligible
non-NASD members who are acting as brokers or agents for investors ("brokers").
Dealers and brokers are sometimes referred to herein as authorized dealers.

Shares may be purchased on any business day by completing the account
application form and forwarding the account application form, directly or
through an authorized dealer, to the Fund's shareholder service agent, Van
Kampen Investor Services Inc. ("Investor Services"), a wholly owned subsidiary
of Van Kampen Investments. When purchasing shares of the Fund, investors must
specify whether the purchase is for Class A Shares, Class B Shares or Class C
Shares by selecting the correct Fund number on the account application form.
Sales personnel of authorized dealers distributing the Fund's shares are
entitled to receive compensation for selling such shares and may receive
differing compensation for selling Class A Shares, Class B Shares or Class C
Shares.

The offering price for shares is based upon the next calculation of net asset
value per share (plus sales

charges, where applicable) after an order is received timely by Investor
Services. Purchases completed through an authorized dealer, custodian, trustee
or record keeper of a retirement plan account may involve additional fees
charged by such person. Orders received by Investor Services prior to the close
of the Exchange, and orders received by authorized dealers prior to the close of
the Exchange that are properly transmitted to Investor Services by the time
designated by Investor Services, are priced based on the date of receipt. Orders
received by Investor Services after the close of the Exchange and orders
received by authorized dealers after the close of the Exchange or orders
received by authorized dealers that are not transmitted to Investor Services
until after the time designated by Investor Services, are priced based on the
date of the next determined net asset value per share provided they are received
timely by Investor Services on such date. It is the responsibility of authorized
dealers to transmit orders received by them to Investor Services so they will be
received in a timely manner.

The Fund and the Distributor reserve the right to refuse any order for the
purchase of shares. The Fund also reserves the right to suspend the sale of the
Fund's shares in response to conditions in the securities markets or for other
reasons.

Investor accounts will automatically be credited with additional shares of the
Fund after any Fund distributions, such as dividends and capital gain dividends,
unless the investor instructs the Fund otherwise. Investors wishing to receive
cash instead of additional shares should contact the Fund by visiting our web
site at www.vankampen.com, by writing to the Fund, c/o Van Kampen Investor
Services Inc., PO Box 947, Jersey City, New Jersey 07303-0947 or by telephone at
(800) 847-2424.

There is no minimum investment amount when establishing an account with the
Fund. However, the Fund may redeem any shareholder account (other than
retirement accounts and accounts established through a broker for which the
transfer agent does not have discretion to initiate transactions) that has been
open for one year or more and has a balance of less than $1,000. Shareholders
will receive written notice at least 60 days in advance of any involuntary
redemption and will be given the opportunity to purchase at net asset value
without sales charge the number of additional shares needed to bring the account
value to $1,000. There will be no involuntary redemption if the value of the
account is less than $1,000 due to market depreciation.

To help the government fight the funding of terrorism and money laundering
activities, federal law requires all financial institutions to obtain, verify,
and record information that identifies each person who opens an account. What
this means to you: when you open an account, you will be asked to provide your
name, address, date of birth, and other information that will allow us to
identify you. The Fund and the Distributor reserve the right to not open your
account if this information is not provided. If the Fund or the Distributor is
unable to verify your identity, the Fund and the Distributor reserve the right
to restrict additional transactions and/or liquidate your account at the next
calculated net asset value after the account is closed (minus any applicable
sales or other charges) or take any other action required by law.

CLASS A SHARES

Class A Shares of the Fund are sold at the offering price, which is net asset
value plus an initial maximum sales charge of up to 4.75% (or 4.99% of the net
amount invested), reduced on investments of $100,000 or more as follows:

CLASS A SHARES
SALES CHARGE SCHEDULE

<Table>
<Caption>
AS % OF AS % OF
SIZE OF OFFERING NET AMOUNT
INVESTMENT PRICE INVESTED
----------------------------------------------------------------

Less than $100,000 4.75% 4.99%
.................................................................
$100,000 but less than
$250,000 3.75% 3.90%
.................................................................
$250,000 but less than
$500,000 2.75% 2.83%
.................................................................
$500,000 but less than
$1,000,000 2.00% 2.04%
.................................................................
$1,000,000 or more * *
.................................................................
</Table>

* No sales charge is payable at the time of purchase on investments of $1
million or more, although for such investments the Fund may impose a
contingent deferred sales charge of 1.00% on certain redemptions made within
one year of the purchase. The contingent deferred sales charge is assessed on
an amount equal to the lesser of the then current market value or the cost of
the shares being

redeemed. Accordingly, no sales charge is imposed on increases in net asset
value above the initial purchase price.

No sales charge is imposed on Class A Shares received from reinvestment of
dividends or capital gain dividends.

Under the Distribution Plan and the Service Plan, the Fund may spend up to a
total of 0.25% per year of the Fund's average daily net assets with respect to
Class A Shares of the Fund. The rates in this paragraph are 0.00% per year of
the Fund's average daily net assets with respect to Class A Shares for accounts
existing from July 1, 1987.

CLASS B SHARES

Class B Shares of the Fund are sold at net asset value and are subject to a
contingent deferred sales charge if redeemed within six years of purchase as
shown in the following table:

CLASS B SHARES
SALES CHARGE SCHEDULE

<Table>
<Caption>
CONTINGENT DEFERRED
SALES CHARGE
AS A PERCENTAGE OF
DOLLAR AMOUNT
YEAR SINCE PURCHASE SUBJECT TO CHARGE
-----------------------------------------------------

First 4.00%
......................................................
Second 3.75%
......................................................
Third 3.50%
......................................................
Fourth 2.50%
......................................................
Fifth 1.50%
......................................................
Sixth 1.00%
......................................................
Seventh and After None
......................................................
</Table>

The contingent deferred sales charge is assessed on an amount equal to the
lesser of the then current market value or the cost of the shares being
redeemed. Accordingly, no sales charge is imposed on increases in net asset
value above the initial purchase price. In addition, no sales charge is assessed
on shares derived from reinvestment of dividends or capital gain dividends. The
Fund will generally not accept a purchase order for Class B Shares in the amount
of $100,000 or more.

The amount of the contingent deferred sales charge, if any, varies depending on
the number of years from the time of each purchase of Class B Shares until the
time of redemption of such shares.

In determining whether a contingent deferred sales charge applies to a
redemption, it is assumed that the shares being redeemed first are any shares in
the shareholder's Fund account that are not subject to a contingent deferred
sales charge, followed by shares held the longest in the shareholder's account.

Under the Distribution Plan, the Fund may spend up to 0.75% per year of the
Fund's average daily net assets with respect to Class B Shares of the Fund. In
addition, under the Service Plan, the Fund may spend up to 0.25% per year of the
Fund's average daily net assets with respect to Class B Shares of the Fund.

CLASS C SHARES

Class C Shares of the Fund are sold at net asset value and are subject to a
contingent deferred sales charge of 1.00% of the dollar amount subject to charge
if redeemed within one year of purchase.

The contingent deferred sales charge is assessed on an amount equal to the
lesser of the then current market value or the cost of the shares being
redeemed. Accordingly, no sales charge is imposed on increases in net asset
value above the initial purchase price. In addition, no sales charge is assessed
on shares derived from reinvestment of dividends or capital gain dividends. The
Fund will not accept a purchase order for Class C Shares in the amount of $1
million or more.

Under the Distribution Plan, the Fund may spend up to 0.75% per year of the
Fund's average daily net assets with respect to Class C Shares of the Fund. In
addition, under the Service Plan, the Fund may spend up to 0.25% per year of the
Fund's average daily net assets with respect to Class C Shares of the Fund.

CONVERSION FEATURE

Class B Shares purchased on or after June 1, 1996, including Class B Shares
received from reinvestment of distributions through the dividend reinvestment
plan on such shares, automatically convert to Class A Shares eight years after
the end of the calendar month in which the shares were purchased. Class B Shares
purchased before June 1, 1996, including Class B Shares received from
reinvestment of distributions through the dividend reinvestment plan on such
shares, automatically convert to Class A Shares six years after the end of the
calendar month in which the shares were purchased. Class C Shares purchased
before January 1, 1997, including Class C Shares received from reinvestment of
distributions through the dividend reinvestment plan on such shares,
automatically convert to Class A Shares ten years after the end of the calendar
month in which the shares were purchased. Such conversion will be on the basis
of the relative net asset values per share, without the imposition of any sales
load, fee or other charge. The conversion schedule applicable to a share of the
Fund acquired through the exchange privilege from another Van Kampen fund
participating in the exchange program is determined by reference to the Van
Kampen fund from which such share was originally purchased.

The conversion of such shares to Class A Shares is subject to the continuing
availability of an opinion of counsel to the effect that (i) the assessment of
the higher distribution fee and transfer agency costs with respect to such
shares does not result in the Fund's dividends or capital gain dividends
constituting "preferential dividends" under the federal income tax law and (ii)
the conversion of shares does not constitute a taxable event under federal
income tax law. The conversion may be suspended if such an opinion is no longer
available and such shares might continue to be subject to the higher aggregate
fees applicable to such shares for an indefinite period.

WAIVER OF CONTINGENT
DEFERRED SALES CHARGE

The contingent deferred sales charge is waived on redemptions of Class B Shares
and Class C Shares (i) within one year following the death or disability (as
disability is defined by federal income tax law) of a shareholder, (ii) for
required minimum distributions from an individual retirement account ("IRA") or
certain other retirement plan distributions, (iii) for withdrawals under the
Fund's systematic withdrawal plan but limited to 12% annually of the initial
value of the account, (iv) if no commission or transaction fee is paid by the
Distributor to authorized dealers at the time of purchase of such shares or (v)
if made by the Fund's involuntary liquidation of a shareholder's account as
described herein. Subject to certain limitations, a shareholder who has redeemed
Class C Shares of the Fund may reinvest in Class C Shares at net asset value
with credit for any contingent deferred sales charge if the reinvestment is made
within 180 days after the redemption, provided that shares of the Fund are
available for sale at the time of reinvestment. For a more complete description
of contingent deferred sales charge waivers, please refer to the Statement of
Additional Information or contact your authorized dealer.

QUANTITY DISCOUNTS

Investors purchasing Class A Shares may, under certain circumstances described
below, be entitled to pay reduced or no sales charges. Investors, or their
authorized dealers, must notify the Fund at the time of the purchase order
whenever a quantity discount is applicable to purchases. Upon such notification,
an investor will pay the lowest applicable sales charge. Quantity discounts may
be modified or terminated at any time. For more information about quantity
discounts, investors should contact their authorized dealer or the Distributor.

A person eligible for a reduced sales charge includes an individual, his or her
spouse and children under 21 years of age and any corporation, partnership or
sole proprietorship which is 100% owned, either alone or in combination, by any
of the foregoing; a trustee or other fiduciary purchasing for a single trust or
for a single fiduciary account, or a "company" as defined in Section 2(a)(8) of
the 1940 Act.

As used herein, "Participating Funds" refers to certain open-end investment
companies advised by Asset Management and distributed by the Distributor as
determined from time to time by the Fund's Board of Trustees.

VOLUME DISCOUNTS. The size of investment shown in the Class A Shares sales
charge table applies to the total dollar amount being invested by any person in
shares of

the Fund, or in any combination of shares of the Fund and shares of other
Participating Funds, although other Participating Funds may have different sales
charges.

CUMULATIVE PURCHASE DISCOUNT. The size of investment shown in the Class A Shares
sales charge table may also be determined by combining the amount being invested
in shares of the Participating Funds plus the current offering price of all
shares of the Participating Funds currently owned.

LETTER OF INTENT. A Letter of Intent provides an opportunity for an investor to
obtain a reduced sales charge by aggregating investments over a 13-month period
to determine the sales charge as outlined in the Class A Shares sales charge
table. The size of investment shown in the Class A Shares sales charge table
includes purchases of shares of the Participating Funds in Class A Shares over a
13-month period based on the total amount of intended purchases plus the value
of all shares of the Participating Funds previously purchased and still owned.
An investor may elect to compute the 13-month period starting up to 90 days
before the date of execution of a Letter of Intent. Each investment made during
the period receives the reduced sales charge applicable to the total amount of
the investment goal. The Letter of Intent does not preclude the Fund (or any
other Participating Fund) from discontinuing the sale of its shares. The initial
purchase must be for an amount equal to at least 5% of the minimum total
purchase amount of the level selected. If trades not initially made under a
Letter of Intent subsequently qualify for a lower sales charge through the
90-day backdating provisions, an adjustment will be made at the expiration of
the Letter of Intent to give effect to the lower sales charge. Such adjustment
in sales charge will be used to purchase additional shares. The Fund initially
will escrow shares totaling 5% of the dollar amount of the Letter of Intent to
be held by Investor Services in the name of the shareholder. In the event the
Letter of Intent goal is not achieved within the specified period, the investor
must pay the difference between the sales charge applicable to the purchases
made and the reduced sales charges previously paid. Such payments may be made
directly to the Distributor or, if not paid, the Distributor will liquidate
sufficient escrowed shares to obtain the difference.

OTHER PURCHASE PROGRAMS

Purchasers of Class A Shares may be entitled to reduced or no initial sales
charges in connection with the unit investment trust reinvestment program and
purchases by registered representatives of selling firms or purchases by persons
affiliated with the Fund or the Distributor. The Fund reserves the right to
modify or terminate these arrangements at any time.

UNIT INVESTMENT TRUST REINVESTMENT PROGRAM. The Fund permits unitholders of unit
investment trusts to reinvest distributions from such trusts in Class A Shares
of the Fund at net asset value without a sales charge if the administrator of an
investor's unit investment trust program meets certain uniform criteria relating
to cost savings by the Fund and the Distributor. The offering price for all
other investments made from unit investment trust distributions will be net
asset value plus an initial maximum sales charge of up to 1.00% (1.01% of the
net amount invested). Of this amount, the Distributor will pay to the authorized
dealer, if any, through which such participation in the qualifying program was
initiated 0.50% of the offering price as a dealer concession or agency
commission. Persons desiring more information with respect to this program,
including the terms and conditions that apply to the program, should contact
their authorized dealer or the Distributor.

The administrator of such a unit investment trust must have an agreement with
the Distributor pursuant to which the administrator will (1) submit a single
bulk order and make payment with a single remittance for all investments in the
Fund during each distribution period by all investors who choose to invest in
the Fund through the program and (2) provide Investor Services with appropriate
backup data for each investor participating in the program in a computerized
format fully compatible with Investor Services' processing system.

To obtain these special benefits, all dividends and other distributions from the
Fund must be reinvested in additional shares and there cannot be any systematic
withdrawal program. The Fund will send account activity statements to such
participants on a quarterly basis only, even if their investments are made more
frequently. The Fund reserves the right to modify or terminate this program at
any time.

NET ASSET VALUE PURCHASE OPTIONS. Class A Shares of the Fund may be purchased at
net asset value without a sales charge, generally upon written assurance that
the purchase is made for investment purposes and that the shares will not be
resold except through redemption by the Fund, by:

(1) Current or retired trustees or directors of funds advised by Morgan Stanley
and any of its subsidiaries and such persons' families and their beneficial
accounts.

(2) Current or retired directors, officers and employees of Morgan Stanley and
any of its subsidiaries; employees of an investment subadviser to any fund
described in (1) above or an affiliate of such subadviser; and such
persons' families and their beneficial accounts.

(3) Directors, officers, employees and, when permitted, registered
representatives, of financial institutions that have a selling group
agreement with the Distributor and their spouses and children under 21
years of age when purchasing for any accounts they beneficially own, or, in
the case of any such financial institution, when purchasing for retirement
plans for such institution's employees; provided that such purchases are
otherwise permitted by such institutions.

(4) Registered investment advisers or financial planners who charge a fee for
their services, trust companies and bank trust departments investing on
their own behalf or on behalf of their clients. The Distributor may pay
authorized dealers through which purchases are made an amount up to 0.50%
of the amount invested, over a 12-month period.

(5) Trustees and other fiduciaries purchasing shares for retirement plans which
invest in multiple fund families through broker-dealer retirement plan
alliance programs that have entered into agreements with the Distributor
and which are subject to certain minimum size and operational requirements.
Trustees and other fiduciaries should refer to the Statement of Additional
Information for further details with respect to such alliance programs.

(6) Beneficial owners of shares of Participating Funds held by a retirement
plan or held in a tax-advantaged retirement account who purchase shares of
the Fund with proceeds from distributions from such a plan or retirement
account other than distributions taken to correct an excess contribution.

(7) Accounts as to which a bank or broker-dealer charges an account management
fee ("wrap accounts"), provided the bank or broker-dealer has a separate
agreement with the Distributor.

(8) Trusts created under pension, profit sharing or other employee benefit
plans; custodial accounts held by a bank created pursuant to Section 403(b)
of the Internal Revenue Code of 1986, as amended (the "Code"); Trusts
sponsored by nonprofit organizations defined under Section 501(c)(3) of the
Code; and assets held by an employer or trustee in connection with an
eligible deferred compensation plan under Section 457 of the Code or in a
"rabbi trust" that meets certain uniform criteria established by the
Distributor from time to time. Such plans will qualify for purchases at net
asset value provided, for plans initially establishing accounts with the
Distributor in the Participating Funds after January 1, 2000, that (a) the
total plan assets are at least $1 million or (b) such shares are purchased
by an employer sponsored plan with more than 100 eligible employees. Such
plans that have been established with a Participating Fund based on net
asset value purchase privileges previously in effect will be qualified to
purchase shares of the Participating Funds at net asset value. Retirement
plans distributed by the Distributor will not be eligible for net asset
value purchases based on the aggregate investment made by the plan or the
number of eligible employees, except under certain uniform criteria
established by the Distributor from time to time. A commission will be paid
to authorized dealers who initiate and are responsible for such purchases
within a rolling twelve-month period as follows: 1.00% on sales to $2
million, plus 0.80% on the next $1 million, plus 0.50% on the next $47
million, plus 0.25% on the excess over $50 million.

(9) Individuals who are members of a "qualified group." For this purpose, a
qualified group is one which (i) has been in existence for more than six
months, (ii) has a purpose other than to acquire shares of the Fund or
similar investments, (iii) has given and continues to give its endorsement
or authorization, on behalf of the group, for purchase of shares of the
Fund and Participating Funds, (iv) has a membership that the authorized
dealer can certify as to the group's members and (v) satisfies other
uniform criteria established by the Distributor for the purpose of
realizing economies of scale in distributing such shares. A qualified group
does not include one whose sole organizational nexus, for example, is that
its participants are credit card holders of the same institution, policy
holders of an insurance company, customers of a bank or broker-dealer,
clients of an investment adviser or other similar groups. Shares purchased
in each group's participants account in connection with this privilege will
be subject to a contingent deferred sales charge of 1.00% in the event of
redemption within one year of purchase, and a commission will be paid to
authorized dealers who initiate and are responsible for such sales to each
individual as follows: 1.00% on sales to $2 million, plus 0.80% on the next
$1 million and 0.50% on the excess over $3 million.

(10) Certain qualified state tuition plans qualifying pursuant to Section 529 of
the Code ("Section 529 Plans") that are approved by the Fund's Distributor.
There is no minimum investment amount for purchases made under this option
(10).

(11) Unit investment trusts sponsored by the Distributor or its affiliates.

The term "families" includes a person's spouse, children and grandchildren under
21 years of age, parents and the parents of the person's spouse.

Purchase orders made pursuant to clause (4) may be placed either through
authorized dealers as described above or directly with Investor Services by the
investment adviser, financial planner, trust company or bank trust department,
provided that Investor Services receives federal funds for the purchase by the
close of business on the next business day following acceptance of the order. An
authorized dealer may charge a transaction fee for placing an order to purchase
shares pursuant to this provision or for placing a redemption order with respect
to such shares. Authorized dealers will be paid a service fee as described above
on purchases made under options (3) through (10) above. The Fund may terminate,
or amend the terms of, offering shares of the Fund at net asset value to such
groups at any time.

Redemption of Shares

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Generally, shareholders may redeem for cash some or all of their shares without
charge by the Fund (other than any applicable sales charge) at any time. As
described under the Prospectus heading "Purchase of Shares," redemptions of
Class B Shares and Class C Shares may be subject to a contingent deferred sales
charge. In addition, certain redemptions of Class A Shares for shareholder
accounts of $1 million or more may be subject to a contingent deferred sales
charge. Redemptions completed through an authorized dealer, custodian, trustee
or record keeper of a retirement plan account may involve additional fees
charged by such person.

Except as specified below under "Telephone Redemption Requests," payment for
shares redeemed generally will be made by check mailed within seven days after
receipt by Investor Services of the redemption request and any other necessary
documents in proper form as described below. Such payment may be postponed or
the right of redemption suspended as provided by the rules of the SEC. Such
payment may, under certain circumstances, be paid wholly or in part by a
distribution-in-kind of portfolio securities. A distribution-in-kind may result
in recognition by the shareholder of a gain or loss for federal income tax
purposes when such securities are distributed, and the shareholder may have
brokerage costs and a gain or loss for federal income tax purposes upon the
shareholder's disposition of such securities. If the shares to be redeemed have
been recently purchased by check, Investor Services may delay the payment of
redemption proceeds until it confirms that the purchase check has cleared, which
may take up to 15 calendar days from the date of purchase. A taxable gain or
loss may

be recognized by the shareholder upon redemption of shares.

WRITTEN REDEMPTION REQUESTS. Shareholders may request a redemption of shares by
written request in proper form sent directly to Van Kampen Investor Services
Inc., PO Box 947, Jersey City, New Jersey 07303-0947. The request for redemption
should indicate the number of shares or dollar amount to be redeemed, the Fund
name and class designation of such shares and the shareholder's account number.
The redemption request must be signed by all persons in whose names the shares
are registered. Signatures must conform exactly to the account registration. If
the proceeds of the redemption exceed $100,000, or if the proceeds are not to be
paid to the record owner at the record address, or if the record address has
changed within the previous 15 calendar days, signature(s) must be guaranteed by
one of the following: a bank or trust company; a broker-dealer; a credit union;
a national securities exchange, a registered securities association or a
clearing agency; a savings and loan association; or a federal savings bank.

Generally, a properly signed written request with any required signature
guarantee is all that is required for a redemption request to be in proper form.
In some cases, however, additional documents may be necessary. Certificated
shares may be redeemed only by written request. The certificates for the shares
being redeemed must be properly endorsed for transfer. Generally, in the event a
redemption is requested by and registered to a corporation, partnership, trust,
fiduciary, estate or other legal entity owning shares of the Fund, a copy of the
corporate resolution or other legal documentation appointing the authorized
signer and certified within the prior 120 calendar days must accompany the
redemption request. Retirement plan distribution requests should be sent to the
plan custodian/trustee to be forwarded to Investor Services. Contact the plan
custodian/trustee for further information.

In the case of written redemption requests sent directly to Investor Services,
the redemption price is the net asset value per share next determined after the
request in proper form is received by Investor Services.

AUTHORIZED DEALER REDEMPTION REQUESTS. Shareholders may place redemption
requests through an authorized dealer following procedures specified by such
authorized dealer. The redemption price for such shares is the net asset value
per share next calculated after an order in proper form is received by an
authorized dealer provided such order is transmitted to the Distributor by the
time designated by the Distributor's close of business on such day. It is the
responsibility of authorized dealers to transmit redemption requests received by
them to the Distributor so they will be received prior to such time. Redemptions
completed through an authorized dealer may involve additional fees charged by
the dealer.

TELEPHONE REDEMPTION REQUESTS. The Fund permits redemption of shares by
telephone and for redemption proceeds to be sent to the address of record for
the account or to the bank account of record as described below. A shareholder
automatically has telephone redemption privileges unless the shareholder
indicates otherwise by checking the applicable box on the account application
form. For accounts that are not established with telephone redemption
privileges, a shareholder may call the Fund at (800) 847-2424 to request that a
copy of the Telephone Redemption Authorization form be sent to the shareholder
for completion or visit our web site at www.vankampen.com to download this form.
Shares may be redeemed by calling (800) 847-2424, our automated telephone
system, which is generally accessible 24 hours a day, seven days a week. Van
Kampen Investments and its subsidiaries, including Investor Services, and the
Fund employ procedures considered by them to be reasonable to confirm that
instructions communicated by telephone are genuine. Such procedures include
requiring certain personal identification information prior to acting upon
telephone instructions, tape-recording telephone communications and providing
written confirmation of instructions communicated by telephone. If reasonable
procedures are employed, none of Van Kampen Investments, Investor Services or
the Fund will be liable for following telephone instructions which it reasonably
believes to be genuine. Telephone redemptions may not be available if the
shareholder cannot reach Investor Services by telephone, whether because all
telephone lines are busy or for any other reason; in such case, a shareholder
would have to use the Fund's other redemption procedures previously described.
Requests received by Investor Services prior to 4:00 p.m., New York time, will
be processed at the next determined net asset value per share. These privileges
are available for

most accounts other than retirement accounts or accounts with shares represented
by certificates. If an account has multiple owners, Investor Services may rely
on the instructions of any one owner.

For redemptions authorized by telephone, amounts of $50,000 or less may be
redeemed daily if the proceeds are to be paid by check or by Automated Clearing
House and amounts of at least $1,000 up to $1 million may be redeemed daily if
the proceeds are to be paid by wire. The proceeds must be payable to the
shareholder(s) of record and sent to the address of record for the account or
wired directly to their predesignated bank account for this account. This
privilege is not available if the address of record has been changed within 15
calendar days prior to a telephone redemption request. Proceeds from redemptions
payable by wire transfer are expected to be wired on the next business day
following the date of redemption. The Fund reserves the right at any time to
terminate, limit or otherwise modify this redemption privilege.

Distributions from the Fund

-------------------------------------------------------------------------------

In addition to any increase in the value of shares which the Fund may achieve,
shareholders may receive distributions from the Fund of dividends and capital
gain dividends.

DIVIDENDS. Interest from investments is the Fund's main source of net investment
income. The Fund's present policy, which may be changed at any time by the
Fund's Board of Trustees, is to declare and distribute monthly, all or
substantially all, of this net investment income as dividends to shareholders.
Dividends are automatically applied to purchase additional shares of the Fund at
the next determined net asset value unless the shareholder instructs otherwise.

The per share dividends on Class B Shares and Class C Shares may be lower than
the per share dividends on Class A Shares as a result of the higher distribution
fees and transfer agency costs applicable to such classes of shares.

CAPITAL GAIN DIVIDENDS. The Fund may realize capital gains or losses when it
sells securities, depending on whether the sales prices for the securities are
higher or lower than purchase prices. The Fund distributes any net capital gains
to shareholders as capital gain dividends at least annually. As in the case of
dividends, capital gain dividends are automatically reinvested in additional
shares of the Fund at the next determined net asset value unless the shareholder
instructs otherwise.

Shareholder Services

-------------------------------------------------------------------------------

Listed below are some of the shareholder services the Fund offers to investors.
For a more complete description of the Fund's shareholder services, such as
investment accounts, share certificates, retirement plans, automated clearing
house deposits, dividend diversification and the systematic withdrawal plan,
please refer to the Statement of Additional Information or contact your
authorized dealer.

INTERNET TRANSACTIONS. In addition to performing transactions on your account
through written instruction or by telephone, you may also perform certain
transactions through the internet. Please refer to our web site at
www.vankampen.com for further instructions regarding internet transactions. Van
Kampen Investments and its subsidiaries, including Investor Services, and the
Fund employ procedures considered by them to be reasonable to confirm that
instructions communicated through the internet are genuine. Such procedures
include requiring use of a personal identification number prior to acting upon
internet instructions and providing written confirmation of instructions
communicated through the internet. If reasonable procedures are employed, none
of Van Kampen Investments, Investor Services or the Fund will be liable for
following instructions received through the internet which it reasonably
believes to be genuine. If an account has multiple owners, Investor Services may
rely on the instructions of any one owner.

REINVESTMENT PLAN. A convenient way for investors to accumulate additional
shares is by accepting dividends and capital gain dividends in shares of the
Fund. Such shares are acquired at net asset value per

share (without a sales charge) on the applicable payable date of the dividend or
capital gain dividend. Unless the shareholder instructs otherwise, the
reinvestment plan is automatic. This instruction may be made by visiting our web
site at www.vankampen.com, by writing to Investor Services or by telephone by
calling (800) 847-2424 ((800) 421-2833 for the hearing impaired). The investor
may, on the account application form or prior to any declaration, instruct that
dividends and/or capital gain dividends be paid in cash, be reinvested in the
Fund at the next determined net asset value or be reinvested in another
Participating Fund at the next determined net asset value.

AUTOMATIC INVESTMENT PLAN. An automatic investment plan is available under which
a shareholder can authorize Investor Services to debit the shareholder's bank
account on a regular basis to invest predetermined amounts in the Fund.
Additional information is available from the Distributor or your authorized
dealer.

CHECK WRITING PRIVILEGE. A Class A shareholder holding shares of the Fund for
which certificates have not been issued and which are not in escrow may write
checks against such shareholder's account by completing the Checkwriting Form
and the appropriate section of the account application form and returning the
forms to Investor Services. Once the forms are properly completed, signed and
returned, a supply of checks (redemption drafts) will be sent to the Class A
shareholder. Checks can be written to the order of any person in any amount of
$100 or more.

When a check is presented to the custodian bank, State Street Bank and Trust
Company (the "Bank"), for payment, full and fractional Class A Shares required
to cover the amount of the check are redeemed from the shareholder's Class A
Shares account by Investor Services at the next determined net asset value per
share. Check writing redemptions represent the sale of Class A Shares. Any gain
or loss realized on the redemption of shares is a taxable event.

Checks will not be honored for redemption of Class A Shares held less than
15-calendar days, unless such Class A Shares have been paid for by bank wire.
Any Class A Shares for which there are outstanding certificates may not be
redeemed by check. If the amount of the check is greater than the proceeds of
all uncertificated shares held in the shareholder's Class A Shares account, the
check will be returned and the shareholder may be subject to additional charges.
A shareholder may not liquidate the entire account by means of a check. The
check writing privilege may be terminated or suspended at any time by the Fund
or by the Bank and neither shall incur any liability for such amendment or
termination or for effecting redemptions to pay checks reasonably believed to be
genuine or for returning or not paying on checks which have not been accepted
for any reason. Retirement plans and accounts that are subject to backup
withholding are not eligible for the check writing privilege.

EXCHANGE PRIVILEGE. Shares of the Fund may be exchanged for shares of the same
class of any Participating Fund based on the next determined net asset value per
share of each fund after requesting the exchange without any sales charge,
subject to certain limitations. Shares of the Fund may be exchanged for shares
of any Participating Fund only if shares of that Participating Fund are
available for sale. Shareholders seeking an exchange into a Participating Fund
should obtain and read the current prospectus for such fund prior to
implementing an exchange. A prospectus of any of the Participating Funds may be
obtained from an authorized dealer or the Distributor or by visiting our web
site at www.vankampen.com.

To be eligible for exchange, shares of the Fund must have been registered in the
shareholder's name for at least 30 days prior to an exchange. Shares of the Fund
registered in a shareholder's name for less than that amount of time may only be
exchanged upon receipt of prior approval of the Adviser. It is the policy of the
Adviser, under normal circumstances, not to approve such requests.

When shares that are subject to a contingent deferred sales charge are exchanged
among Participating Funds, the holding period for purposes of computing the
contingent deferred sales charge is based upon the date of the initial purchase
of such shares from a Participating Fund. When such shares are redeemed and not
exchanged for shares of another Participating Fund, the shares are subject to
the contingent deferred sales charge schedule imposed by the Participating Fund
from which such shares were originally purchased.

Exchanges of shares are sales of shares of one Participating Fund and purchases
of shares of another Participating Fund. The sale may result in a gain or loss
for federal income tax purposes. If the shares sold have been held for less than
91 days, the sales charge paid on such shares is carried over and included in
the tax basis of the shares acquired.

A shareholder wishing to make an exchange may do so by sending a written request
to Investor Services, by calling (800) 847-2424, our automated telephone system,
which is generally accessible 24 hours a day, seven days a week or by visiting
our web site at www.vankampen.com. A shareholder automatically has these
exchange privileges unless the shareholder indicates otherwise by checking the
applicable box on the account application form. Van Kampen Investments and its
subsidiaries, including Investor Services, and the Fund employ procedures
considered by them to be reasonable to confirm that instructions communicated by
telephone are genuine. Such procedures include requiring certain personal
identification information prior to acting upon telephone instructions,
tape-recording telephone communications, and providing written confirmation of
instructions communicated by telephone. If reasonable procedures are employed,
none of Van Kampen Investments, Investor Services or the Fund will be liable for
following telephone instructions which it reasonably believes to be genuine. If
the exchanging shareholder does not have an account in the fund whose shares are
being acquired, a new account will be established with the same registration,
dividend and capital gain dividend options (except dividend diversification) and
authorized dealer of record as the account from which shares are exchanged,
unless otherwise specified by the shareholder. In order to establish a
systematic withdrawal plan for the new account or reinvest dividends from the
new account into another fund, however, an exchanging shareholder must submit a
specific request.

The Fund reserves the right to reject any order to purchase its shares through
exchange or otherwise. Certain patterns of past exchanges and/or purchase or
sale transactions involving the Fund or other Participating Funds may result in
the Fund limiting or prohibiting, in the Fund's discretion, additional purchases
and/or exchanges. Determinations in this regard may be made based on the
frequency or dollar amount of the previous exchanges or purchases or sale
transactions. Generally, all shareholders are limited to a maximum of eight
exchanges per fund during a rolling 365-day period. Exchange privileges will be
suspended on a particular fund if more than eight exchanges out of that fund are
made by a shareholder during a rolling 365-day period. If exchange privileges
are suspended, subsequent exchange requests during the stated period will not be
processed. Exchange privileges will be restored when the account history shows
fewer than eight exchanges in the rolling 365-day period. This eight exchange
policy does not apply to systematic exchange plans or employer-sponsored
retirement plans. The Fund may modify, restrict or terminate the exchange
privilege at any time. Shareholders will receive 60 days' notice of any
termination or material amendment.

For purposes of determining the sales charge rate previously paid on Class A
Shares, all sales charges paid on the exchanged shares and on any shares
previously exchanged for such shares or for any of their predecessors shall be
included. If the exchanged shares were acquired through reinvestment, those
shares are deemed to have been sold with a sales charge rate equal to the rate
previously paid on the shares on which the dividend or distribution was paid. If
a shareholder exchanges less than all of such shareholder's shares, the shares
upon which the highest sales charge rate was previously paid are deemed
exchanged first.

Exchange requests received on a business day prior to the time shares of the
funds involved in the request are priced will be processed on the date of
receipt. "Processing" a request means that shares of the fund which the
shareholder is redeeming will be redeemed at the net asset value per share next
determined on the date of receipt. Shares of the fund that the shareholder is
purchasing will also normally be purchased at the net asset value per share,
plus any applicable sales charge, next determined on the date of receipt.
Exchange requests received on a business day after the time that shares of the
funds involved in the request are priced will be processed on the next business
day in the manner described herein.

Federal Income Taxation

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Distributions of the Fund's investment company taxable income (generally
ordinary income and net short-term capital gain) are taxable to shareholders as
ordinary income to the extent of the Fund's earnings and profits, whether paid
in cash or reinvested in additional shares. Distributions of the Fund's net
capital gain (which is the excess of net long-term capital gain over net
short-term capital loss) designated as capital gain dividends, if any, are
taxable to shareholders as long-term capital gains, whether paid in cash or
reinvested in additional shares, and regardless of how long the shares of the
Fund have been held by such shareholders. The Fund expects that its
distributions will consist primarily of ordinary income and capital gain
dividends. Distributions in excess of the Fund's earnings and profits will first
reduce the adjusted tax basis of a shareholder's shares and, after such adjusted
tax basis is reduced to zero, will constitute capital gains to such shareholder
(assuming such shares are held as a capital asset).

The Jobs and Growth Tax Relief Reconciliation Act of 2003 (the "2003 Tax Act")
contains provisions that reduce the U.S. federal income tax rates on (1) long-
term capital gains received by individuals and (2) "qualified dividend income"
received by individuals from certain domestic and foreign corporations. The
reduced rate for capital gains generally applies to long-term capital gains from
sales or exchanges on or after May 6, 2003, and ceases to apply for taxable
years beginning after December 31, 2008. The reduced rate for dividends
generally applies to "qualified dividend income" received in taxable years
beginning after December 31, 2002, and ceases to apply for taxable years
beginning after December 31, 2008. Because the Fund intends to invest primarily
in debt securities, ordinary income dividends paid by the Fund generally will
not be eligible for the reduced rate applicable to "qualified dividend income."
To the extent that distributions from the Fund are designated as capital gain
dividends, such distributions will be eligible for the reduced rate applicable
to long-term capital gains. No assurance can be given that Congress will not
repeal the reduced U.S. federal income tax rate on long-term capital gains prior
to its scheduled expiration under the 2003 Tax Act.

Although distributions generally are treated as taxable in the year they are
paid, distributions declared in October, November or December, payable to
shareholders of record on a specified date in such month and paid during January
of the following year will be treated as having been distributed by the Fund and
received by the shareholders on the December 31st prior to the date of payment.
The Fund will inform shareholders of the source and tax status of all
distributions promptly after the close of each calendar year.

The sale or exchange of shares may be a taxable transaction for federal income
tax purposes. Shareholders who sell their shares will generally recognize a gain
or loss in an amount equal to the difference between their adjusted tax basis in
the shares sold and the amount received. If the shares are held by the
shareholder as a capital asset, the gain or loss will be a capital gain or loss.
As a consequence of the 2003 Tax Act, the maximum tax rate applicable to net
capital gains recognized by individuals and other non-corporate taxpayers on the
sale or exchange of shares is (i) the same as the maximum ordinary income tax
rate for capital assets held for one year or less or (ii) for net capital gains
recognized on or after May 6, 2003, 15% for capital assets held for more than
one year (20% for net capital gains recognized in taxable years beginning after
December 31, 2008). No assurance can be given that Congress will not repeal the
reduced U.S. federal income tax rate on long-term capital gains prior to its
scheduled expiration under the 2003 Tax Act.

Backup withholding rules require the Fund, in certain circumstances, to withhold
28% of dividends and certain other payments, including redemption proceeds, paid
to shareholders who do not furnish to the Fund their correct taxpayer
identification number (in the case of individuals, their social security number)
and make certain required certifications (including certifications as to foreign
tax status, if applicable) or who are otherwise subject to backup withholding.

Foreign shareholders, including shareholders who are non-resident aliens, may be
subject to U.S. withholding tax on certain distributions (whether received in
cash or in shares) at a rate of 30% or such lower rate as prescribed by an
applicable treaty. Dividends paid by the Fund will be subject to such U.S.
withholding tax, whereas interest income with respect to a direct

investment in the underlying assets of the Fund by a foreign shareholder may not
be subject to U.S. withholding tax. Prospective foreign investors should consult
their advisers concerning the tax consequences to them of an investment in
shares of the Fund.

The Fund has elected and qualified, and intends to continue to qualify, as a
regulated investment company under federal income tax law. If the Fund so
qualifies and distributes each year to its shareholders at least 90% of its
investment company taxable income, the Fund will not be required to pay federal
income taxes on any income it distributes to shareholders. If the Fund
distributes less than an amount equal to the sum of 98% of its ordinary income
and 98% of its capital gain net income, then the Fund will be subject to a 4%
excise tax on the undistributed amounts.

Investments of the Fund in securities issued at a discount or providing for
deferred interest or payment of interest in kind are subject to special tax
rules that will affect the amount, timing and character of distributions to
shareholders. For example, with respect to securities issued at a discount, the
Fund will be required to accrue as income each year a portion of the discount
and to distribute such income each year to maintain its qualification as a
regulated investment company and to avoid income and excise taxes. To generate
sufficient cash to make distributions necessary to satisfy the 90% distribution
requirement and to avoid income and excise taxes, the Fund may have to dispose
of securities that it would otherwise have continued to hold.

The federal income tax discussion set forth above is for general information
only. Shareholders and prospective investors should consult their own advisers
regarding the specific federal tax consequences of purchasing, holding and
disposing of shares of the Fund, as well as the effects of state, local and
foreign tax laws and any proposed tax law changes.

Financial Highlights

---------------------------------------------------------------------------

The financial highlights table is intended to help you understand the Fund's
financial performance for the periods indicated. Certain information
reflects financial results for a single Fund share. The total returns in the
table represent the rate that an investor would have earned (or lost) on an
investment in the Fund (assuming reinvestment of all distributions and not
including payment of the maximum sales charge or taxes on Fund distributions
or redemptions). The information for the fiscal years ended March 31, 2004,
2003, 2002 and 2001 has been audited by Ernst & Young LLP, an independent
registered public accounting firm, whose report, along with the Fund's most
recent financial statements, is included in the Statement of Additional
Information and may be obtained without charge by calling the telephone
number on the back cover of this Prospectus. The information for the fiscal
year ended March 31, 2000, has been audited by the Fund's former auditors.
The financial highlights table should be read in conjunction with the
financial statements and notes thereto included in the Statement of
Additional Information.
<Table>
<Caption>
CLASS A SHARES
YEAR ENDED MARCH 31,
---------------------------------------------------------------
2004 2003 2002(f) 2001 2000
-------------------------------------------------------------------------------------------------

Net Asset Value, Beginning
of the Period.............. $5.00 $5.69 $7.18 $8.48 $9.03
------ ------ ------- ------ ------
Net Investment Income...... .37 .48 .69 .94 .85
Net Realized and Unrealized
Gain/Loss................ .52 (.60) (1.38) (1.40) (.56)
------ ------ ------- ------ ------
Total from Investment
Operations................. .89 (.12) (.69) (.46) .29
------ ------ ------- ------ ------
Less:
Distributions from Net
Investment Income........ .34 .49 .77 .84 .83
Return of Capital
Distributions............ .06 .08 .03 -0- .01
------ ------ ------- ------ ------
Total Distributions......... .40 .57 .80 .84 .84
------ ------ ------- ------ ------
Net Asset Value, End of the
Period..................... $5.49 $5.00 $5.69 $7.18 $8.48
====== ====== ======= ====== ======
Total Return*............... 18.35%(a) -1.62%(a) -10.05%(a) -5.64%(a) 3.50%(a)
Net Assets at End of the
Period (In millions)....... $198.1 $191.0 $177.2 $205.8 $230.6
Ratio of Expenses to Average
Net Assets*(d)............. 1.19% 1.21% 1.22% 1.17% 1.15%
Ratio of Net Investment
Income to Average Net
Assets*.................... 7.25% 8.94% 10.90% 12.00% 9.96%
Portfolio Turnover.......... 104% 101% 78% 85% 109%
*If certain expenses had
not been voluntarily
assumed by the Adviser,
total return would have
been lower and the ratios
would have been as
follows:
Ratio of Expenses to Average
Net Assets................. 1.29% 1.31% 1.32% 1.27% 1.25%
Ratio of Net Investment
Income to Average Net
Assets..................... 7.15% 8.84% 10.80% 11.90% 9.86%

<Caption>
CLASS B SHARES
YEAR ENDED MARCH 31,
-----------------------------------------------------------
2004 2003 2002(g) 2001 2000
---------------------------- ---------------------------------------------------------------

Net Asset Value, Beginning
of the Period.............. $5.02 $5.71 $7.20 $8.49 $9.03
------ ------ ------- ------ ------
Net Investment Income...... .34 .43 .63 .87 .80
Net Realized and Unrealized
Gain/Loss................ .52 (.59) (1.38) (1.39) (.58)
------ ------ ------- ------ ------
Total from Investment
Operations................. .86 (.16) (.75) (.52) .22
------ ------ ------- ------ ------
Less:
Distributions from Net
Investment Income........ .30 .45 .72 .77 .75
Return of Capital
Distributions............ .06 .08 .02 -0- .01
------ ------ ------- ------ ------
Total Distributions......... .36 .53 .74 .77 .76
------ ------ ------- ------ ------
Net Asset Value, End of the
Period..................... $5.52 $5.02 $5.71 $7.20 $8.49
====== ====== ======= ====== ======
Total Return*............... 17.62%(b) -2.37%(b) -10.70%(b) -6.39%(b) 2.65%(b)
Net Assets at End of the
Period (In millions)....... $94.8 $79.6 $78.8 $92.5 $109.2
Ratio of Expenses to Average
Net Assets*(d)............. 1.94% 1.96% 1.98% 1.92% 1.93%
Ratio of Net Investment
Income to Average Net
Assets*.................... 6.50% 8.23% 10.13% 11.22% 9.17%
Portfolio Turnover.......... 104% 101% 78% 85% 109%
*If certain expenses had
not been voluntarily
assumed by the Adviser,
total return would have
been lower and the ratios
would have been as
follows:
Ratio of Expenses to Average
Net Assets................. 2.04% 2.06% 2.08% 2.02% 2.03%
Ratio of Net Investment
Income to Average Net
Assets..................... 6.40% 8.13% 10.03% 11.12% 9.07%

<Caption>
CLASS C SHARES
YEAR ENDED MARCH 31,
-----------------------------------------------------------
2004 2003 2002(f) 2001(e) 2000
---------------------------- -------------------------------------------------------------------

Net Asset Value, Beginning
of the Period.............. $5.01 $5.70 $7.19 $8.47 $9.02
------ ------ ------- ------ -----
Net Investment Income...... .33 .44 .63 .87 .80
Net Realized and Unrealized
Gain/Loss................ .53 (.60) (1.38) (1.38) (.58)
------ ------ ------- ------ -----
Total from Investment
Operations................. .86 (.16) (.75) (.51) .22
------ ------ ------- ------ -----
Less:
Distributions from Net
Investment Income........ .30 .45 .71 .77 .76
Return of Capital
Distributions............ .06 .08 .03 -0- .01
------ ------ ------- ------ -----
Total Distributions......... .36 .53 .74 .77 .77
------ ------ ------- ------ -----
Net Asset Value, End of the
Period..................... $5.51 $5.01 $5.70 $7.19 $8.47
====== ====== ======= ====== =====
Total Return*............... 17.65%(c) -2.38%(c) -10.72%(c) -6.40%(c) 2.65%(c)
Net Assets at End of the
Period (In millions)....... $30.4 $19.8 $17.7 $14.7 $13.0
Ratio of Expenses to Average
Net Assets*(d)............. 1.94% 1.97% 1.97% 1.92% 1.93%
Ratio of Net Investment
Income to Average Net
Assets*.................... 6.49% 8.23% 10.10% 11.19% 9.17%
Portfolio Turnover.......... 104% 101% 78% 85% 109%
*If certain expenses had
not been voluntarily
assumed by the Adviser,
total return would have
been lower and the ratios
would have been as
follows:
Ratio of Expenses to Average
Net Assets................. 2.04% 2.07% 2.07% 2.02% 2.03%
Ratio of Net Investment
Income to Average Net
Assets..................... 6.39% 8.13% 10.00% 11.09% 9.07%
</Table>

(a) Assumes reinvestment of all distributions for the period and does not
include payment of the maximum sales charge of 4.75% or contingent
deferred sales charge (CDSC). On purchases of $1 million or more, a CDSC
of 1% may be imposed on certain redemptions made within one year of
purchase. If the sales charge was included, total returns would be
lower. These returns include combined Rule 12b-1 fees and service fees
of up to .25% and do not reflect the deduction of taxes that a
shareholder would pay on Fund distributions or the redemption of Fund
shares.

(b) Assumes reinvestment of all distributions for the period and does not
include payment of the maximum CDSC of 4%, charged on certain
redemptions made within one year of purchase and declining to 0% after
the sixth year. If the sales charge was included, total returns would be
lower. These returns include combined Rule 12b-1 fees and service fees
of 1% and do not reflect the deduction of taxes that a shareholder would
pay on Fund distributions or the redemption of Fund shares.

(c) Assumes reinvestment of all distributions for the period and does not
include payment of the maximum CDSC of 1%, charged on certain
redemptions made within one year of purchase. If the sales charge was
included, total returns would be lower. These returns include combined
Rule 12b-1 fees and service fees of 1% and do not reflect the deduction
of taxes that a shareholder would pay on Fund distributions or the
redemption of Fund shares.

(d) The Ratio of Expenses to Average Net Assets does not reflect credits
earned on cash balances. If these credits were reflected as a reduction
of expenses, the ratio would decrease by .01% for the period ended March
31, 2001.

(e) Based on average shares outstanding.

(f) As required, effective April 1, 2001, the Fund has adopted the
provisions of the AICPA Audit and Accounting Guide for Investment
Companies and began amortizing premium on fixed income securities. The
effect of this change for the year ended March 31, 2002 was to decrease
net investment income per share by $.01, increase net realized and
unrealized gains and losses per share by $.01 and decrease the Ratio of
Net Investment Income to Average Net Assets by .09%. Per share, ratios
and supplemental data for periods prior to March 31, 2002 have not been
restated to reflect this change in presentation.

(g) As required, effective April 1, 2001, the Fund has adopted the
provisions of the AICPA Audit and Accounting Guide for Investment
Companies and began amortizing premium on fixed income securities. The
effect of this change for the year ended March 31, 2002 was to decrease
net investment income per share by $.01, increase net realized and
unrealized gains and losses per share by $.01 and decrease the Ratio of
Net Investment Income to Average Net Assets by .10%. Per share, ratios
and supplemental data for periods prior to March 31, 2002 have not been
restated to reflect this change in presentation.

Appendix -- Description

of Securities Ratings

-------------------------------------------------------------------------------

STANDARD & POOR'S -- A brief description of the applicable Standard & Poor's
(S&P) rating symbols and their meanings (as published by S&P) follows:

A S&P issue credit rating is a current opinion of the creditworthiness of an
obligor with respect to a specific financial obligation, a specific class of
financial obligations, or a specific financial program. It takes into
consideration the creditworthiness of guarantors, insurers, or other forms of
credit enhancement on the obligation. The issue credit rating is not a
recommendation to purchase, sell, or hold a financial obligation, inasmuch as it
does not comment as to market price or suitability for a particular investor.

Issue credit ratings are based on current information furnished by the obligors
or obtained by S&P from other sources it considers reliable. S&P does not
perform an audit in connection with any credit rating and may, on occasion, rely
on unaudited financial information. Credit ratings may be changed, suspended, or
withdrawn as a result of changes in, or unavailability of, such information, or
based on other circumstances.

Issue credit ratings can be either long-term or short-term. Short-term ratings
are generally assigned to those obligations considered short-term in the
relevant market. In the U.S., for example, that means obligations with an
original maturity of no more than 365 days including commercial paper.
Short-term ratings are also used to indicate the creditworthiness of an obligor
with respect to put features on long-term obligations. The result is a dual
rating, in which the short-term ratings address the put feature, in addition to
the usual long-term rating. Medium-term notes are assigned long-term ratings.

LONG-TERM ISSUE CREDIT RATINGS

Issue credit ratings are based in varying degrees, on the following
considerations:

1. Likelihood of payment -- capacity and willingness of the insurer to meet its
financial commitment on an obligation in accordance with the terms of the
obligation:

2. Nature of and provisions of the obligation: and

3. Protection afforded by, and relative position of, the obligation in the event
of bankruptcy, reorganization, or other arrangement under the laws of
bankruptcy and other laws affecting creditors' rights.

The issue rating definitions are expressed in terms of default risk. As such,
they pertain to senior obligations of an entity. Junior obligations are
typically rated lower than senior obligations, to reflect the lower priority in
bankruptcy, as noted above.

AAA: An obligation rated "AAA" has the highest rating assigned by S&P. The
obligor's capacity to meet its financial commitment on the obligation is
extremely strong.

AA: An obligation rated "AA" differs from the highest-rated obligations only in
small degree. The obligor's capacity to meet its financial commitment on the
obligation is very strong.

A: An obligation rated "A" is somewhat more susceptible to the adverse effects
of changes in circumstances and economic conditions than obligations in
higher-rated categories. However, the obligor's capacity to meet its financial
commitment on the obligation is still strong.

BBB: An obligation rated "BBB" exhibits adequate protection parameters. However,
adverse economic conditions or changing circumstances are more likely to lead to
a weakened capacity of the obligor to meet its financial commitment on the
obligation.

SPECULATIVE GRADE

BB, B, CCC, CC, C: Obligations rated "BB", "B", "CCC", "CC" and "C" are regarded
as having significant speculative characteristics. "BB" indicates the least
degree of speculation and "C" the highest. While such obligations will likely
have some quality and protective characteristics, these may be outweighed by
large uncertainties or major exposures to adverse conditions.

A-1

BB: An obligation rated "BB" is less vulnerable to nonpayment than other
speculative issues. However, it faces major ongoing uncertainties or exposure to
adverse business, financial, or economic conditions which could lead to the
obligor's inadequate capacity to meet its financial commitment on the
obligation.

B: An obligation rated "B" is more vulnerable to nonpayment than obligations
rated "BB", but the obligor currently has the capacity to meet its financial
commitment on the obligation. Adverse business, financial, or economic
conditions will likely impair the obligor's capacity or willingness to meet its
financial commitment on the obligation.

CCC: An obligation rated "CCC" is currently vulnerable to nonpayment and is
dependent upon favorable business, financial, and economic conditions for the
obligor to meet its financial commitment on the obligation. In the event of
adverse business, financial, or economic conditions, the obligor is not likely
to have the capacity to meet its financial commitment on the obligation.

CC: An obligation rated "CC" is currently highly vulnerable to nonpayment.

C: The "C" rating may be used to cover a situation where a bankruptcy petition
has been filed or similar action has been taken, but payments on this obligation
are being continued.

D: An obligation rated "D" is in payment default. The "D" rating category is
used when payments on an obligation are not made on the date due even if the
applicable grace period has not expired, unless S&P believes that such payments
will be made during such grace period. The "D" rating also will be used upon the
filing of a bankruptcy petition or the taking of a similar action if payments on
an obligation are jeopardized.

Plus (+) or minus (-): The ratings from 'AA' to 'CCC' may be modified by the
addition of a plus or minus sign to show relative standing within the major
rating categories.

c: The "c" subscript is used to provide additional information to investors that
the bank may terminate its obligation to purchase tendered bonds if the
long-term credit rating of the issuer is below an investment-grade level and/or
the issuer's bonds are deemed taxable.

p: The letter "p" indicates that the rating is provisional. A provisional rating
assumes the successful completion of the project financed by the debt being
rated and indicates that payment of debt service requirements is largely or
entirely dependent upon the successful, timely completion of the project. This
rating, however, while addressing credit quality subsequent to completion of the
project, makes no comment on the likelihood of or the risk of default upon
failure of such completion. The investor should exercise his own judgment with
respect to such likelihood and risk.

*: Continuance of the ratings is contingent upon S&P's receipt of an executed
copy of the escrow agreement or closing documentation confirming investments and
cash flows.

r: The "r" highlights derivative, hybrid, and certain other obligations that
S&P's believes may experience high volatility or high variability in expected
returns as a result of noncredit risks. Examples of such obligations are
securities with principal or interest return indexed to equities, commodities,
or currencies; certain swaps and options; and interest-only and principal-only
mortgage securities. The absence of an "r" symbol should not be taken as an
indication that an obligation will exhibit no volatility or variability in total
return.

N.R.: Not rated.

Debt obligations of issuers outside the United States and its territories are
rated on the same basis as domestic corporate and municipal issues. The ratings
measure the creditworthiness of the obligor but do not take into account
currency exchange and related uncertainties.

BOND INVESTMENT QUALITY STANDARDS

Under present commercial bank regulations issued by the Comptroller of the
Currency, bonds rated in the top four categories ("AAA", "AA", "A", "BBB",
commonly known as investment-grade ratings) generally are regarded as eligible
for bank investment. Also, the laws of various states governing legal
investments impose certain rating or other standards for obligations eligible
for investment by savings banks, trust companies, insurance companies, and
fiduciaries in general.

A-2

COMMERCIAL PAPER

A S&P commercial paper rating is a current assessment of the likelihood of
timely payment of debt considered short-term in the relevant market.

Ratings are graded into several categories, ranging from "A-1" for the highest
quality obligations to "D" for the lowest. These categories are as follows:

A-1: A short-term obligation rated "A-1" is rated in the highest category by
S&P's. The obligor's capacity to meet its financial commitment on the obligation
is strong. Within this category, certain obligations are designated with a plus
sign (+). This indicates that the obligor's capacity to meet its financial
commitment on these obligations is extremely strong.

A-2: A short-term obligation rated "A-2" is somewhat more susceptible to the
adverse effects of changes in circumstances and economic conditions than
obligations in higher rating categories. However, the obligor's capacity to meet
its financial commitment on the obligation is satisfactory.

A-3: A short-term obligation rated "A-3" exhibits adequate protection
parameters. However, adverse economic conditions or changing circumstances are
more likely to lead to a weakened capacity of the obligor to meet its financial
commitment on the obligation.

B: A short-term obligation rated "B" is regarded as having significant
speculative characteristics. The obligor currently has the capacity to meet its
financial commitment on the obligation; however, it faces major ongoing
uncertainties which could lead to the obligor's inadequate capacity to meet its
financial commitment on the obligation.

C: A short-term obligation rated "C" is currently vulnerable to nonpayment and
is dependent upon favorable business, financial, and economic conditions for the
obligor to meet its financial commitment on the obligation.

D: A short-term obligation rated "D" is in payment default. The "D" rating
category is used when payments on an obligation are not made on the date due
even if the applicable grace period has not expired, unless S&P's believes that
such payments will be made during such grace period. The "D" rating also will be
used upon the filing of a bankruptcy petition or the taking of a similar action
if payments on an obligation are jeopardized.

A commercial paper rating is not a recommendation to purchase, sell or hold a
financial obligation inasmuch as it does not comment as to market price or
suitability for a particular investor. The ratings are based on current
information furnished to S&P by the issuer or obtained from other sources it
considers reliable. S&P does not perform an audit in connection with any rating
and may, on occasion, rely on unaudited financial information. The ratings may
be changed, suspended or withdrawn as a result of changes in, or unavailability
of, such information, or based on other circumstances.

MOODY'S INVESTORS SERVICE INC. -- A brief description of the applicable Moody's
Investors Service, Inc. (Moody's) rating symbols and their meanings (as
published by Moody's) follows:

Aaa: Obligations rated Aaa are judged to be of the highest quality, with minimal
credit risk.

Aa: Obligations rated Aa are judged to be of high quality and are subject to
very low credit risk.

A: Obligations rated A are considered upper-medium grade and are subject to low
credit risk.

Baa: Obligations rated Baa are subject to moderate credit risk. They are
considered medium-grade and as such may possess certain speculative
characteristics.

Ba: Obligations rated Ba are judged to have speculative elements and are subject
to substantial credit risk.

B: Obligations rated B are considered speculative and are subject to high credit
risk.

Caa: Obligations rated Caa are judged to be of poor standing and are subject to
very high credit risk.

Ca: Obligations rated Ca are highly speculative and are likely in, or very near,
default, with some prospect of recovery of principal and interest.

A-3

C: Obligations rated C are the lowest rated class of bonds and are typically in
default, with little prospect for recovery of principal or interest.

Note: Moody's appends numerical modifiers 1, 2, and 3 to each generic rating
classification from Aa through Caa. The modifier 1 indicates that the obligation
ranks in the higher end of its generic rating category; the modifier 2 indicates
a mid-range ranking; and the modifier 3 indicates a ranking in the lower end of
that generic rating category.

MEDIUM-TERM NOTE RATINGS

Moody's assigns long-term ratings to individual debt securities issued from
medium-term note (MTN) programs, in addition to indicating ratings to MTN
programs themselves. Notes issued under MTN programs with such indicated ratings
are rated at issuance at the rating applicable to all pari passu notes issued
under the same program, at the program's relevant indicated rating, provided
such notes do not exhibit any of the characteristics listed below:

- Notes containing features that link interest or principal to the credit
performance of any third party or parties

- Notes allowing for negative coupons, or negative principal.

- Notes containing any provision which could obligate the investor to make any
additional payments.

- Notes containing provisions that subordinate the claim.

For notes with any of these characteristics, the rating of the individual note
may differ from the indicated rating of the program.

Market participants must determine whether any particular note is rated, and if
so, at what rating level. Moody's encourages market participants to contact
Moody's Ratings Desks or visit www.moodys.com directly if they have questions
regarding ratings for specific notes issued under a medium-term note program.
Unrated notes issued under an MTN program may be assigned an NR symbol.

ABSENCE OF A RATING: Where no rating has been assigned or where a rating has
been withdrawn, it may be for reasons unrelated to the creditworthiness of the
issue.

Should no rating be assigned, the reason may be one of the following:

1. An application was not received or accepted.

2. The issue or issuer belongs to a group of securities or entities that are not
rated as a matter of policy.

3. There is a lack of essential data pertaining to the issue or issuer.

4. The issue was privately placed, in which case the rating is not published in
Moody's publications.

Suspension or withdrawal may occur if new and material circumstances arise, the
effects of which preclude satisfactory analysis; if there is no longer available
reasonable up-to-date data to permit a judgment to be formed; if a bond is
called for redemption; or for other reasons.

A-4

For More Information

-------------------------------------------------------------------------------

EXISTING SHAREHOLDERS OR PROSPECTIVE INVESTORS
- Call your broker
- WEB SITE
www.vankampen.com
- FUNDINFO(R)
Automated Telephone System 800-847-2424

DEALERS
- WEB SITE
www.vankampen.com
- FUNDINFO(R)
AUTOMATED TELEPHONE SYSTEM 800-847-2424
- VAN KAMPEN INVESTMENTS 800-421-5666

TELECOMMUNICATIONS DEVICE FOR THE DEAF (TDD)
- For shareholder and dealer inquiries through TDD, call 800-421-2833

VAN KAMPEN HIGH YIELD FUND
1221 Avenue of the Americas
New York, New York 10020

Investment Adviser
VAN KAMPEN ASSET MANAGEMENT
1221 Avenue of the Americas
New York, New York 10020

Distributor
VAN KAMPEN FUNDS INC.
1221 Avenue of the Americas
New York, New York 10020

Transfer Agent
VAN KAMPEN INVESTOR SERVICES INC.
PO Box 947
Jersey City, New Jersey 07303-0947
Attn: Van Kampen High Yield Fund

Custodian
STATE STREET BANK AND TRUST COMPANY
225 West Franklin Street, PO Box 1713
Boston, Massachusetts 02110-1713
Attn: Van Kampen High Yield Fund

Legal Counsel
SKADDEN, ARPS, SLATE, MEAGHER & FLOM LLP
333 West Wacker Drive
Chicago, Illinois 60606

Independent Registered Public Accounting Firm
ERNST & YOUNG LLP
233 South Wacker Drive
Chicago, Illinois 60606

Van Kampen
High Yield Fund

A Statement of Additional Information, which contains more details about the
Fund, is incorporated by reference in its entirety into this Prospectus.

You will find additional information about the Fund
in its annual and semiannual reports to shareholders.
The annual report explains the market conditions and
investment strategies affecting the Fund's performance during
its last fiscal year.

You can ask questions or obtain a free copy of the Fund's reports or its
Statement of Additional Information by calling (800) 847-2424.
Telecommunications Device for the Deaf users may call (800) 421-2833. A free
copy of the Fund's reports and its Statement of Additional Information are
available from our web site at www.vankampen.com.

Information about the Fund, including its reports and Statement of Additional
Information, has been filed with the Securities and Exchange Commission (SEC).
It can be reviewed and copied at the SEC's Public Reference Room in Washington,
DC or on the EDGAR database on the SEC's internet site (http://www.sec.gov).
Information on the operation of the SEC's Public Reference Room may be obtained
by calling the SEC at 1-202-942-8090. You can also request copies of these
materials, upon payment of a duplicating fee, by electronic request at the SEC's
e-mail address (publicinfo@sec.gov) or by writing the Public Reference section
of the SEC, Washington, DC 20549-0102.

JULY 30, 2004

CLASS A SHARES
CLASS B SHARES
CLASS C SHARES

PROSPECTUS

[VAN KAMPEN INVESTMENTS LOGO]
The Fund's Investment Company HYF PRO 7/04
Act File No. is 811-4629.