VAN KAMPEN ANNOUNCES CHANGES
TO VAN KAMPEN SENIOR LOAN FUND
TENDER OFFER

September 30, 2005

Recently, Van Kampen Investments announced enhancements to the Van Kampen
Senior Loan Fund. As part of these product enhancements, effective February 18,
2005, please note that the tender offer period and process have now changed.

The Fund now makes regular offers to repurchase its shares in order to
provide liquidity to shareholders. The repurchase offer is an opportunity for
shareholders to sell shares on a periodic basis. Previously, the tender offer
had to be approved by the Board of Trustees, and there were no assurances that
the Fund would offer a quarterly tender. Pursuant to the recent modifications,
the Fund now offers a regular quarterly repurchase period. In addition, the Fund
is currently seeking exemptive relief to conduct monthly repurchase offers.
There is no assurance, however, that such exemptive relief will be granted.

Please note the following changes to this process:

- The dates for this quarter's Van Kampen Senior Loan Fund repurchase
offer period are September 30 through the close of the New York
Stock Exchange (normally the Exchange closes at 4:00 p.m., Eastern
Time, but may close earlier on certain days) on October 21, 2005 for
Class A, B, C, IB and IC shares. The Fund is offering to repurchase
a portion of its outstanding shares at a price equal to the
respective net asset value per class of common shares of the Fund on
the repurchase pricing date, as more fully described in the enclosed
Repurchase Offer Terms.

- Prior to each repurchase offer period, the Fund will send
notification to all Van Kampen Senior Loan Fund shareholders,
including those accountholders whose shares are held in networked
accounts or omnibus positions. For all repurchase offer periods,
shareholders will be mailed the following documents no less than 21
days prior to the repurchase request deadline:

- A letter outlining the repurchase procedure

- Van Kampen Senior Loan Fund Shareholder Repurchase Offer Notice

- Repurchase Offer Terms

- Letter Of Transmittal

SHAREHOLDERS WHO ARE NOT INTERESTED IN SELLING OR EXCHANGING SHARES CAN
DISREGARD THE PACKET.

- You may continue to place trades through your back office; please
follow your internal procedures.

- Van Kampen sponsored retirement plan shareholders with State Street
Bank and Trust Company as custodian who wish to sell their shares
must complete and submit the appropriate Van Kampen retirement
account distribution form in addition to the enclosed Letter of
Transmittal. To obtain a distribution form, you may download forms
at www.vankampen.com.

For information on recent enhancements to the Van Kampen Senior Loan Fund,
read the Fund prospectus or Van Kampen InFocus.

If you have any questions, please call your Van Kampen representative:

<Table>

* National Broker/Dealer Division (800) 826-5267

* Financial Institutions Division (800) 852-2656

* Financial Advisors Division (800) 421-7571

* Insurance Division (800) 778-3237

* Regional Broker/Dealer Division (800) 607-9281

* Fee Based Division (800) 607-8862

* National Account Manager (800) 225-2222

* Client Relations or Account Servicing (800) 421-5666

* Main Office Operations:

VKIS Brokerage Operations Support Services (800) 421-3863
</Table>

VAN KAMPEN SENIOR LOAN FUND
FUND FACTS

<Table>
<Caption>
SYMBOL CUSIP
------ ---------

A Shares................................................... VSLAX 920914306
B Shares................................................... VSLBX 920914405
C Shares................................................... VSLCX 920914504
IB Shares*................................................. XPRTX 920914108
IC Shares*................................................. XSLCX 920914207
</Table>

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

* Closed to all new investments other than dividend or capital gain
reinvestment.

THIS LETTER IS FOR FINANCIAL PROFESSIONAL USE ONLY.

Van Kampen Funds Inc.
1 Parkview Plaza, P.O. Box 5555
Oakbrook Terrace, IL 60181-5555
www.vankampen.com

Copyright (C)2005
Van Kampen Funds Inc.
All rights reserved.
Member NASD/SIPC. (VAN KAMPEN INVESTMENTS LOGO)
64 SLT009-9/05

September 30, 2005

To Van Kampen Senior Loan Fund Shareholders:

As part of recent modifications of the Van Kampen Senior Loan Fund, the
Fund now makes regular offers to repurchase its shares in order to provide
liquidity to shareholders. The repurchase offers are an opportunity for you to
sell shares on a periodic basis. Prior to each repurchase offer period, the Fund
now sends notification to all Van Kampen Senior Loan Fund shareholders.

IF YOU ARE NOT INTERESTED IN SELLING OR EXCHANGING YOUR FUND SHARES AT THIS
TIME, YOU DO NOT HAVE TO DO ANYTHING AND CAN DISREGARD THIS NOTICE.

If you intend to sell or exchange your shares during this repurchase offer
period, please read the enclosed documents. You should also consider the
following:

- Determine if your account is held with your financial advisor or
directly with Van Kampen. If you are unsure if your account is held
directly with Van Kampen or with your financial advisor, please
review your most recent account statement. If your statement is from
your financial advisor, you must contact your financial advisor for
assistance. If your statement is from Van Kampen, you may either
contact your financial advisor or you can contact Van Kampen.

- IF YOUR ACCOUNT IS HELD WITH YOUR FINANCIAL ADVISOR, THERE MAY BE
DIFFERENT REQUIREMENTS FOR MAKING A REPURCHASE REQUEST DURING THE
REPURCHASE OFFER. PLEASE CONTACT YOUR FINANCIAL ADVISOR BEFORE
COMPLETING THESE DOCUMENTS.

- If you wish to sell shares held in a Van Kampen sponsored retirement
plan account with State Street Bank and Trust Company serving as
custodian, you must complete and submit the appropriate Van Kampen
retirement account distribution form in addition to the enclosed
Letter of Transmittal to execute your request. To obtain a
distribution form, please contact our Client Relations Department
immediately at 1-800-847-2424 or you may download the form at
www.vankampen.com.

The enclosed documents apply only to the current repurchase offer period,
and new documents will be mailed to you in connection with subsequent offers.

Please refer to the Fund's Prospectus and the enclosed Van Kampen Senior
Loan Fund Shareholder Repurchase Offer Notice, Repurchase Offer Terms and Letter
of Transmittal if you have any questions.

Very truly yours,

VAN KAMPEN SENIOR LOAN FUND

64 SLT00007-9/05

September 30, 2005

VAN KAMPEN SENIOR LOAN FUND
SHAREHOLDER REPURCHASE OFFER NOTICE

This notice is to inform you of the dates for your Fund's next quarterly
repurchase offer. IF YOU ARE NOT INTERESTED IN SELLING YOUR SHARES AT THIS TIME,
YOU DO NOT HAVE TO DO ANYTHING AND CAN DISREGARD THIS NOTICE.

This is a legally required notification of the scheduled quarterly
repurchase offer. The Fund will contact you again next quarter to remind you of
the next repurchase offer period, unless the Securities and Exchange Commission
permits us to conduct monthly repurchase offers prior to then, in which case we
will contact you at the commencement of the first monthly repurchase offer.

We extend this quarterly repurchase offer to provide liquidity to
shareholders because shares of this closed-end interval fund are not redeemable
daily for cash and are not traded on a stock exchange. You can sell Fund shares
only during one of the Fund's scheduled quarterly repurchase offer periods, so
we would like to make you aware of the deadlines and procedures should you wish
to do so. NOTE THAT EARLY WITHDRAWAL OF SHARES FROM THE FUND MAY RESULT IN A
SALES CHARGE AND MAY BE A TAXABLE EVENT; consult your financial advisor or tax
advisor for more information. Please remember that you are not obligated to do
anything with your shares at this time.

This quarter's repurchase offer period begins on September 30, 2005. Please
note, this quarter's repurchase offer ends (unless extended) on the repurchase
request deadline at the close of the New York Stock Exchange (normally the
Exchange closes at 4:00 p.m., Eastern Time, but may close earlier on certain
days) on October 21, 2005. Shares accepted for repurchase will be purchased at a
price equal to the respective net asset value of such shares on the repurchase
pricing date, which is described further in the enclosed Repurchase Offer Terms.
On September 23, 2005, the net asset values per share of the Fund's Class A,
Class B, Class C, Class IB and Class IC shares were $9.08, $9.08, $9.08, $9.09
and $9.08, respectively.

If you wish to sell your shares for cash or exchange your shares for shares
of other participating funds during this repurchase offer period, you can do so
in one of three ways as follows:

1. IF YOUR SHARES ARE HELD FOR YOU BY YOUR BROKER-DEALER, OR FOR YOUR
RETIREMENT PLAN BY YOUR RETIREMENT PLAN TRUSTEE OR OTHERWISE BY A NOMINEE,
YOU WILL NEED TO ASK YOUR BROKER-DEALER OR RETIREMENT PLAN TRUSTEE OR
NOMINEE TO SUBMIT THE REPURCHASE REQUEST FOR YOU.

2. IF YOUR SHARES ARE HELD IN YOUR OWN NAME, COMPLETE THE ENCLOSED
LETTER OF TRANSMITTAL AND INSURE THAT IT IS RECEIVED IN GOOD ORDER BY VAN
KAMPEN INVESTOR SERVICES INC., THE FUND'S DEPOSITARY, PRIOR TO THE CLOSE OF
THE NEW YORK STOCK EXCHANGE (NORMALLY THE EXCHANGE CLOSES AT 4:00 P.M.,
EASTERN TIME, BUT MAY CLOSE EARLIER ON CERTAIN DAYS) ON OCTOBER 21, 2005.
PLEASE CONTACT YOUR FINANCIAL ADVISOR TO DISCUSS WHETHER THE SHARES ARE
HELD IN YOUR NAME OR IN THE FINANCIAL ADVISOR'S NAME.

3. IF YOUR SHARES ARE HELD IN A VAN KAMPEN SPONSORED RETIREMENT PLAN
ACCOUNT WITH STATE STREET BANK AND TRUST COMPANY SERVING AS CUSTODIAN,
PLEASE BE AWARE THAT VAN KAMPEN REQUIRES A COMPLETED DISTRIBUTION FORM FOR
YOUR SPECIFIC RETIREMENT ACCOUNT TYPE, IN ADDITION TO THE ENCLOSED LETTER
OF TRANSMITTAL IN ORDER TO PROCESS YOUR REQUEST. To obtain a distribution
form, please contact our Client Relations Department immediately at
1-800-847-2424, or you may download forms at www.vankampen.com.

IF YOU ARE UNSURE WHICH OF THE ABOVE SITUATIONS APPLIES TO YOU, PLEASE
CONTACT YOUR FINANCIAL ADVISOR.

ALL DOCUMENTATION RELATING TO REPURCHASE REQUESTS MUST BE RECEIVED IN GOOD
ORDER PRIOR TO THE CLOSE OF THE NEW YORK STOCK EXCHANGE (NORMALLY THE EXCHANGE
CLOSES AT 4:00 P.M., EASTERN TIME, BUT MAY CLOSE EARLIER ON CERTAIN DAYS) ON
OCTOBER 21, 2005.

Please refer to the Fund's Prospectus and the enclosed Repurchase Offer
Terms and Letter of Transmittal if you have any questions, or you can also call
us at 1-800-847-2424 or your financial advisor. The enclosed documents apply
only to the current repurchase offer period, and new documents will be mailed to
you in connection with subsequent offers.

No person has been authorized to make any recommendation, to give you any
information or to make any representations to you in connection with this
repurchase offer (other than those contained herein, in the Repurchase Offer
Terms, in the Letter of Transmittal, in the letter outlining the repurchase
procedure or in the Fund's Prospectus) and, if given or made, such information
must not be relied upon as having been authorized by the Fund, its investment
adviser, its principal underwriter or its transfer agent.

Van Kampen Funds Inc.
1 Parkview Plaza, P.O. Box 5555
Oakbrook Terrace, IL 60181-5555
www.vankampen.com
Van Kampen Funds Inc.
Copyright (C)2005 Van Kampen Funds Inc. All rights reserved.
Member NASD/SIPC. (VAN KAMPEN INVESTMENTS LOGO)
64SLT004(a)-9/05

REPURCHASE OFFER TERMS

1. THE OFFER. Van Kampen Senior Loan Fund (the "Fund") is offering to
repurchase for cash up to fifteen percent (15%) of the aggregate of its issued
and outstanding Class A, Class B, Class C, Class IB and Class IC shares of
beneficial interest ("Shares") on the repurchase request deadline (described
below) at a price equal to the respective net asset value ("NAV" or "Net Asset
Value") as of the close of the New York Stock Exchange on the repurchase pricing
date (described below), less any applicable early withdrawal charge (described
below), upon the terms and conditions set forth in this Repurchase Offer Terms,
the Van Kampen Senior Loan Fund Shareholder Repurchase Offer Notice (the
"Repurchase Offer Notice"), the Fund's Prospectus, and the related Letter of
Transmittal. Together those documents constitute the "Offer". The purpose of the
Offer is to provide liquidity to shareholders of the Fund. The Offer is not
conditioned upon the tender for repurchase of any minimum number of Shares. All
classes of Shares are considered to be a single class for the purposes of
allocating repurchases under this Offer. The purpose of the Offer is to provide
liquidity to shareholders since the Fund is unaware of any secondary market
which exists for the Shares. The Fund currently does not charge a processing fee
for handling repurchase requests. However, if your Shares are held for you by
your broker-dealer, or for your retirement plan by your retirement plan trustee
or otherwise by a nominee, such person may charge a transaction fee for
submitting a repurchase request for you.

2. NET ASSET VALUE. You must determine whether to tender Shares prior to
the repurchase request deadline, but the Net Asset Values at which the Fund will
repurchase Shares will not be calculated until the repurchase pricing date. The
Net Asset Values may fluctuate between the date you submit your repurchase
request and the repurchase request deadline (and the repurchase pricing date, if
different.) The Net Asset Values on the repurchase request deadline and the
repurchase pricing date could be higher or lower than on the date you submit a
repurchase request. Please call the Fund at 1-800-847-2424, for current NAV
information.

3. REPURCHASE REQUEST DEADLINE. All tenders of Shares for repurchase must
be received in proper form by the Fund's transfer agent, Van Kampen Investor
Services Inc., on or before the close of the New York Stock Exchange (normally
the Exchange closes at 4:00 p.m., Eastern Time, but may close earlier on certain
days) on October 21, 2005, unless extended (the "repurchase request deadline").

4. REPURCHASE PRICING DATE. The Net Asset Values per share of the Fund's
Class A, Class B, Class C, Class IB and IC Shares for the repurchase must be
determined no later than 14 days after the repurchase request deadline (or the
next business day if the 14th day is not a business day); however, the Fund
intends to determine NAV on the repurchase request deadline, if doing so is not
likely to result in significant dilution of the price of the Shares, or as soon
as such determination can be made thereafter (the "repurchase pricing date"). If
the Fund chooses a repurchase pricing date later than the repurchase request
deadline, there is a risk that the Fund's Net Asset Values per share may
fluctuate between those dates.

5. PAYMENT FOR SHARES REPURCHASED. Payment for all Shares repurchased
pursuant to this Offer will be made not later than seven days after the
repurchase pricing date.

6. EARLY WITHDRAWAL CHARGE. The Fund does not currently charge a special
handling or processing fee for repurchases. Your financial adviser or broker may
charge a transaction fee in connection with submitting a repurchase request. An
early withdrawal charge of up to 3% may be imposed on those Class B Shares
accepted for repurchase that have been held for less than five years. An early
withdrawal charge of up to 1% may be imposed on those Class C Shares accepted
for repurchase that have been held for less than 1 year. Also, an early
withdrawal charge of up to 1% may be imposed on certain Class A Shares accepted
for repurchase that have been held for less than 18 months and that were not
subject to a front-end sales load at the time of purchase. Please check your
holdings and the Fund's Prospectus.

7. INCREASE IN NUMBER OF SHARES REPURCHASED; PRO RATA REPURCHASE. If
shareholders tender for repurchase more than the Shares which the Fund is
offering to repurchase, the Fund may (but is not obligated to) increase the
number of Shares that the Fund is offering to repurchase by up to 2% of the
number of Shares outstanding on the repurchase request deadline. If the number
of Shares tendered for repurchase thereafter exceeds the number of Shares which
the Fund is offering to repurchase, the Fund is required to repurchase the
Shares tendered on a pro rata basis. There can be no assurance that the Fund
will be able to repurchase all the Shares that you tender even if you tender all
the Shares that you own. In the event of an oversubscribed Offer, you may be
unable to liquidate some or all of your investment at Net Asset Value. You may
have to wait until a subsequent repurchase offer to tender Shares that the Fund
was unable to repurchase, and you would be subject to the risk of Net Asset
Value fluctuations during that time.

8. WITHDRAWAL OR MODIFICATION OF NUMBER OF SHARES TO BE REPURCHASED. Shares
submitted pursuant to the Offer may be withdrawn or you may change the number of
Shares submitted for repurchase at any time prior to the close of the New York
Stock Exchange (normally the Exchange closes at 4:00 p.m., Eastern Time, but may
close earlier on certain days) on the repurchase request deadline. If your
Shares are held for you by your broker-dealer, or for your retirement plan by
your retirement plan trustee or otherwise by a nominee, please consult such
person if you wish to modify or

withdraw a repurchase request. With respect to Shares held directly,
shareholders seeking to modify or withdraw their tender of Shares must send to
the Fund's depositary, Van Kampen Investor Services Inc., at the address noted
in the Letter of Transmittal, a notice of withdrawal or notice of modification,
as applicable, that specifies the name of the person withdrawing or modifying a
tender of Shares, the number of Shares to be withdrawn or the modified number of
Shares to be tendered and, if certificates representing such Shares have been
delivered or otherwise identified to the depositary, the name of the registered
holder(s) of such Shares. If certificates have been delivered to the depositary,
then, prior to the release of such certificates, you must also submit the
certificate numbers shown on the particular certificates evidencing such Shares,
and the signature on the notice of withdrawal or notice of modification must be
guaranteed. (See Instruction 4(f) to the Letter of Transmittal for further
instructions regarding acceptable guarantees of signatures.) Shares properly
withdrawn shall not thereafter be deemed to be tendered for purposes of the
Offer. However, withdrawn Shares may be retendered by following the procedures
described herein prior to the repurchase request deadline. For further
information regarding modifications or withdrawals of tenders, you may call the
Fund at 1-800-847-2424, or contact your financial adviser.

9. SUSPENSION OR POSTPONEMENT OF REPURCHASE OFFER. The Board of Trustees of
the Fund may suspend or postpone this Offer only by a majority vote of the
Trustees (including a majority of the disinterested Trustees) and only:

(A) for any period during which the New York Stock Exchange or any
market in which the securities owned by the Fund are principally traded is
closed, other than customary weekend and holiday closings, or during which
trading in such market is restricted; or

(B) for any period during which an emergency exists as a result of
which disposal by the Fund of securities owned by it is not reasonably
practicable, or during which it is not reasonably practicable for the Fund
fairly to determine the value of its net assets; or

(C) if the Offer would cause the Fund to lose its status as a
regulated investment company under Subchapter M of the Internal Revenue
Code; or

(D) for such other periods as the Securities and Exchange Commission
may by order permit for the protection of shareholders of the Fund.

If the Offer is suspended or postponed, the Fund will provide notice to
each shareholder of the Fund's Shares of the suspension or postponement. If the
Fund renews the Offer, the Fund will send a new notification to each shareholder
with details concerning the terms and conditions of the renewed Offer.

NEITHER THE FUND NOR ITS BOARD OF TRUSTEES MAKES ANY RECOMMENDATION TO ANY
SHAREHOLDER AS TO WHETHER TO TENDER OR REFRAIN FROM TENDERING SHARES. EACH
SHAREHOLDER MUST MAKE AN INDEPENDENT DECISION WHETHER TO TENDER SHARES AND, IF
SO, HOW MANY SHARES TO TENDER. NO PERSON HAS BEEN AUTHORIZED TO MAKE ANY
RECOMMENDATION ON BEHALF OF THE FUND AS TO WHETHER SHAREHOLDERS SHOULD TENDER
SHARES PURSUANT TO THIS OFFER. NO PERSON HAS BEEN AUTHORIZED TO GIVE ANY
INFORMATION OR TO MAKE ANY REPRESENTATIONS IN CONNECTION WITH THE OFFER OTHER
THAN THOSE CONTAINED HEREIN, IN THE REPURCHASE OFFER NOTICE, IN THE LETTER OF
TRANSMITTAL, IN THE LETTER OUTLINING THE REPURCHASE PROCEDURE OR IN THE FUND'S
PROSPECTUS.

FOR A COPY OF THE FUND'S PROSPECTUS OR OTHER INFORMATION, VISIT
WWW.VANKAMPEN.COM, CALL THE FUND AT 1-800-847-2424, OR CONTACT YOUR FINANCIAL
ADVISER.

Dated: September 30, 2005
64SLT004(b)-9/05

-------------------------------------------------------------------------------
(tear along dotted line)

LETTER OF TRANSMITTAL
REGARDING SHARES
OF

VAN KAMPEN SENIOR LOAN FUND
TENDERED PURSUANT TO THE VAN KAMPEN SENIOR LOAN FUND SHAREHOLDER REPURCHASE
OFFER NOTICE AND
REPURCHASE OFFER TERMS
DATED SEPTEMBER 30, 2005

THE REPURCHASE OFFER (THE "OFFER") AND WITHDRAWAL RIGHTS EXPIRE AT THE CLOSE OF
THE NEW YORK STOCK EXCHANGE (NORMALLY THE EXCHANGE CLOSES AT 4:00 P.M., EASTERN
TIME, BUT MAY CLOSE EARLIER ON CERTAIN DAYS) ON OCTOBER 21, 2005 (UNLESS
EXTENDED)
IF YOUR SHARES ARE HELD FOR YOU BY YOUR FINANCIAL ADVISOR,
PLEASE CONTACT YOUR FINANCIAL ADVISOR DIRECTLY.

Ladies and Gentlemen:

The undersigned hereby tenders to the Van Kampen Senior Loan Fund (formerly
known as Van Kampen Prime Rate Income Trust), a non-diversified, closed-end
management investment company organized as a Massachusetts business trust (the
"Fund"), the common shares of beneficial interest, par value $0.01 per share,
which are offered in five classes of shares designated as Class A Shares, Class
B Shares, Class C Shares, Class IB Shares and Class IC Shares (collectively, the
"Shares"), of the Fund described below in Box No. 1, at a price (the "Purchase
Price") equal to the respective net asset value per class of Shares ("NAV")
determined as of the repurchase pricing date (as described in the Repurchase
Offer Terms), upon the terms and conditions set forth in the Van Kampen Senior
Loan Fund Shareholder Repurchase Offer Notice and the Repurchase Offer Terms,
each dated September 30, 2005, receipt of which is hereby acknowledged, and in
this Letter of Transmittal and the Instructions hereto (which together
constitute the "Offer"). An early withdrawal charge (as described in the
Repurchase Offer Terms) will be imposed on most Class B Shares and Class C
Shares accepted for payment which have been held for less than five years and
one year, respectively and upon certain Class A Shares which have been held for
less than 18 months and which were not subject to a front-end sales load at the
time of purchase.

Subject to and effective upon acceptance for payment of the Shares tendered
hereby in accordance with the terms of the Offer, the undersigned hereby sells,
assigns and transfers to or upon the order of the Fund all right, title and
interest in and to all Shares tendered hereby that are purchased pursuant to the
Offer and hereby irrevocably constitutes and appoints Van Kampen Investor
Services Inc. (the "Depositary") as attorney-in-fact of the undersigned with
respect to such Shares, with full power of substitution (such power of attorney
being deemed to be an irrevocable power coupled with an interest), to: (a)
deliver certificates for such Shares or transfer ownership of such Shares on the
Fund's books, together in either such case with all accompanying evidences of
transfer and authenticity, to or upon the order of the Fund, upon receipt by the
Depositary, as the undersigned's agent, of the respective NAV per class of
Shares with respect to such Shares; (b) present certificates for such Shares, if
any, for cancellation and transfer on the Fund's books; (c) deduct from the
Purchase Price deposited with the Depositary any applicable early withdrawal
charge and remit such charge to Van Kampen Funds Inc.; and (d) receive all
benefits and otherwise exercise all rights of beneficial ownership of such
Shares, subject to the next paragraph, all in accordance with the terms of the
Offer.

The undersigned hereby represents and warrants that: (a) the undersigned
has a "net long position" in the Shares tendered hereby within the meaning of
Rule 14e-4 promulgated under the Securities Act of 1934, as amended, and has
full power and authority to validly tender, sell, assign and transfer the Shares
tendered hereby; (b) when and to the extent the Fund accepts the Shares for
purchase, the Fund will acquire good, marketable and unencumbered title to them,
free and clear of all security interests, liens, charges, encumbrances,
conditional sales agreements or other obligations relating to their sale or
transfer, and not subject to any adverse claim; (c) on request, the undersigned
will execute and deliver any additional documents the Depositary or the Fund
deems necessary or desirable to complete the assignment, transfer and purchase
of the Shares tendered hereby; and (d) the undersigned has read and agrees to
all of the terms of this Offer.

The names and addresses of the registered owners should be printed, if they
are not already printed, in Box 1 as they appear on the registration of the
Shares. The tendering shareholder must select the "Cash" option to have the cash
proceeds from the tendered Shares paid in cash or select the "Exchange" option
to have the Depositary invest the cash proceeds of the Offer in shares of the
same class, in the case of Class A Shares, Class B Shares or Class C Shares of
the Fund, or invest the cash proceeds of the Offer in Class A Shares, in the
case of Class IB Shares and Class IC Shares of the Fund, in each case of certain
investment companies advised by Van Kampen Asset Management and distributed by
Van Kampen Funds Inc., subject to certain limitations. The tendering shareholder
must further indicate one of several options, either (A) to specify all Shares
be tendered, (B) a specified number of Shares be tendered or (C) that number of
Shares tendered necessary to obtain a specific dollar amount. If the Shares
tendered hereby are in certificate form, the certificates representing such
Shares must be returned together with this Letter of Transmittal.

The undersigned recognizes that under certain circumstances set forth in
the Offer, the Fund may terminate or amend the Offer or may not be required to
purchase any of the Shares tendered hereby. In any such event, the undersigned
understands that certificate(s) for any Shares not purchased, if any, will be
returned to the undersigned at the address indicated below in Box No. 1 unless
otherwise indicated under the Special Payment and Delivery Instructions in Box
No. 2.

The undersigned understands that acceptance of Shares by the Fund for
payment will constitute a binding agreement between the undersigned and the Fund
upon the terms and subject to the conditions of the Offer.

The check for the Purchase Price of the tendered Shares purchased, minus
any applicable early withdrawal charge, will be issued to the order of the
undersigned and mailed to the address indicated below in Box No. 1, unless
otherwise indicated in Box No. 2. Shareholders tendering Shares remain entitled
to receive dividends declared on such shares up to the settlement date of the
Offer. The Fund will not pay interest on the Purchase Price under any
circumstances.

All authority herein conferred or agreed to be conferred shall survive the
death or incapacity of the undersigned and all obligations of the undersigned
hereunder shall be binding upon the heirs, personal representatives, successors
and assigns of the undersigned. Except as stated in the Offer, this tender is
irrevocable.

THIS LETTER OF TRANSMITTAL IS TO BE USED ONLY IF THE SHARES TO BE TENDERED
ARE REGISTERED IN THE SHAREHOLDER'S NAME AND THE NECESSARY DOCUMENTS WILL BE
TRANSMITTED TO THE DEPOSITARY BY THE SHAREHOLDER OR HIS BROKER, DEALER OR OTHER
SELLING GROUP MEMBER. DO NOT USE THIS FORM IF A BROKER, DEALER OR OTHER SELLING
GROUP MEMBER IS THE REGISTERED OWNER OF THE SHARES AND IS EFFECTING THE
TRANSACTION FOR THE SHAREHOLDER.

DELIVERY TO AN ADDRESS OTHER THAN THAT SHOWN BELOW DOES NOT CONSTITUTE VALID
DELIVERY.

IF SHARES ARE HELD IN YOUR OWN NAME, SEND TO:
VAN KAMPEN INVESTOR SERVICES INC., Depositary

<Table>

By Regular Mail: By Certified, Registered,
Van Kampen Investor Services Inc. Overnight Mail or Courier:
P.O. Box 947 Van Kampen Investor Services Inc.
Jersey City, NJ 07303-0947 Harborside Financial Center
Attn: Van Kampen Plaza Two, 2nd Floor
Senior Loan Fund Tender Jersey City, NJ 07311-3977
Attn: Van Kampen
Senior Loan Fund Tender
</Table>

FOR ADDITIONAL INFORMATION CALL:
(800) 847-2424.
IF YOUR SHARES ARE HELD FOR YOU BY YOUR FINANCIAL ADVISOR,
PLEASE CONTACT YOUR FINANCIAL ADVISOR DIRECTLY.
64 SLT004(a)-9/05

-------------------------------------------------------------------------------
(tear along dotted line)

VAN KAMPEN SENIOR LOAN FUND

IF THE SHARES TENDERED HEREBY ARE IN CERTIFICATE FORM, THE CERTIFICATES
REPRESENTING SUCH SHARES MUST BE RETURNED TOGETHER WITH THIS LETTER OF
TRANSMITTAL. PLEASE NOTE THAT WE SUGGEST THAT SUCH CERTIFICATES BE RETURNED VIA
CERTIFIED OR REGISTERED MAIL.

TO ENSURE PROCESSING OF YOUR REQUEST, THIS LETTER OF TRANSMITTAL OR A
MANUALLY SIGNED FACSIMILE OF IT (TOGETHER WITH ANY CERTIFICATES FOR SHARES AND
ALL OTHER REQUIRED DOCUMENTS) MUST BE RECEIVED BY THE DEPOSITARY ON OR BEFORE
THE REPURCHASE REQUEST DEADLINE (OCTOBER 21, 2005, UNLESS EXTENDED).

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

<Table>

BOX NO. 1: SHAREHOLDER INFORMATION
- -------------------------------------------------------------------------------------------------------
Name and Address of Registered Owner Shareholder Information
- -------------------------------------------------------------------------------------------------------

PLEASE PROVIDE: Social Security/Tax
Identification No. -----------------------------
Confirm No. -------------------
(if applicable)
ACCOUNT NO.:
- ---------------------------------------------------
</Table>

CHOOSE BETWEEN CASH OR EXCHANGE, THEN SELECT AN OPTION

1. CASH: I understand that an early withdrawal charge will be imposed on most
Class B Shares and Class C Shares accepted for payment that have been held for
less than five years and one year, respectively, and upon certain Class A
Shares which have been held for less than 18 months and which were not subject
to a front-end sales load at the time of purchase, and that such charge, if
any, will be deducted from the proceeds from the tender of such Shares.
OPTION A: ____ (ALL) I hereby tender ALL of my Shares of the Fund.
OPTION B: ____ (SHARES) I hereby tender ____________ Shares of the Fund.
OPTION C: ____ (DOLLARS) I hereby tender that number of Shares of the Fund
necessary to receive $____________ from the Fund after the early withdrawal
charge, if any, is deducted.
2. EXCHANGE: I elect to have the proceeds from such tender invested into
shares of the same class, in the case of Class A Shares, Class B Shares or
Class C Shares of the Fund, or into Class A Shares, in the case of Class IB or
Class IC Shares of the Fund, in each case of Van Kampen
____________________________________ Fund (Shareholder Acct. No.
____________________________________, if applicable).
OPTION A: ____ (ALL) I hereby exchange ALL of my Shares of the Fund.
OPTION B: ____ (SHARES) I hereby exchange ____________ Shares of the Fund.
OPTION C: ____ (DOLLARS) I hereby exchange that number of Shares of the Fund
necessary to have $____________ invested into shares of the above designated
fund.
PLEASE NOTE:
1. A TENDER REQUEST THAT DOES NOT SPECIFY CASH OR EXCHANGE OR THAT DOES NOT
SPECIFY ALL, A NUMBER OF SHARES OR AN AMOUNT OF DOLLARS WILL BE REJECTED.
2. Alterations to this form (i.e. the repurchase request deadline or share
class, etc.) are prohibited and the request will be rejected.
3. Additional legal documentation may be required.
4. For shareholders electing the "Exchange" option, in order to use certain
shareholder services (including certain purchase, redemption and exchange
privileges) on the share account, a signature guarantee form will be
required for such account; shareholders may access materials to establish
these privileges by calling the Client Relations Department at (800)
847-2424 or accessing applicable forms at http://www.vankampen.com by
selecting the Literature section and then Forms.
5. If the account indicated by the account number in Box No. 1 is a Van Kampen
retirement plan custodial account (sponsored by Van Kampen Funds Inc.) of
which State Street Bank and Trust Company serves as custodian, a Van Kampen
distribution form MUST be submitted with this Letter of Transmittal.
6. If the social security number or other tax identification number is not
certified OR the account is being transferred to a new social security
number or other tax identification number, a Form W-9 MUST be completed and
signed by the account owner. (Estate accounts must be signed by the legal
representative of the estate and bear the estate's tax identification
number and not the social security number of the deceased. Completion of
the Form W-9 certifies the tax identification number. Certification will
prevent backup withholding pursuant to the Internal Revenue Code and
applicable Treasury regulations.) See Instruction 8. Non-U.S. shareholders
should provide an appropriate Form W-8 to avoid withholding pursuant to the
Internal Revenue Code and applicable Treasury Regulations. See Instruction
9.

PLEASE BE SURE TO COMPLETE BOTH SIDES OF THIS FORM

<Table>

------------------------------------------------------------------------------------------------------
BOX NO. 2: SPECIAL PAYMENT AND DELIVERY INSTRUCTIONS (SEE INSTRUCTIONS 2, 3 AND 4)
------------------------------------------------------------------------------------------------------
To be completed ONLY if any checks are to be sent or wired to someone other than the undersigned
and/or any checks or certificates for Shares not tendered or not purchased are to be sent to the
undersigned at an address other than that shown above in Box No. 1. A SIGNATURE GUARANTEE IS REQUIRED
IF THIS PORTION IS COMPLETED.
------------------------------------------------------------------------------------------------------
CHECK/CERTIFICATE INFORMATION BANK WIRE INFORMATION
------------------------------------------------------------------------------------------------------
PAYEE: Wire Proceeds To: [ ] Checking [ ] Savings
If you would like the check and/or certificates (Minimum $5,000 to be wired)
PAYABLE to someone other than who the account is
registered, please provide the following: Bank ------------------------------------------
(NAME)
Name(s) ---------------------------------------
(PLEASE PRINT) Address ---------------------------------------
Address --------------------------------------- ABA Routing No. -------------------------------
--------------------------------------- Account No. -----------------------------------
(INCLUDE ZIP CODE) (SHAREHOLDER'S BANK ACCOUNT NO.)
MAILING: Bank Account Registration ---------------------
If you would like the check and/or certificates (NAME)
MAILED to an address other than the account
registration, please provide the following: Please attach a voided check or deposit slip if
possible.
Name(s) ---------------------------------------
(PLEASE PRINT)
Address ---------------------------------------
---------------------------------------
(INCLUDE ZIP CODE)
------------------------------------------------------------------------------------------------------
</Table>

BOX NO. 3: SIGNATURES (SEE INSTRUCTIONS 2, 3 AND 4)
- --------------------------------------------------------------------------------

A. By signing this Letter of Transmittal, you represent that you have read
the letter printed on the other side of this page and the Instructions
enclosed herewith, which Instructions form part of the terms and
conditions of the Offer.

B. This Letter of Transmittal must be signed by the registered owner(s) of
the Shares tendered hereby or by person(s) authorized to become
registered owner(s) by documents transmitted herewith. If signature is by
attorney-in-fact, executor, administrator, trustee, guardian, officer of
a corporation or another acting in a fiduciary or representative
capacity, please set forth the name and full title of such authorized
signor and include the required additional legal documentation regarding
the authority of the signor. See Instruction 4.

NOTE: ANY QUESTIONS REGARDING ADDITIONAL LEGAL DOCUMENTATION WHICH MAY
BE REQUIRED SHOULD BE DIRECTED TO OUR CLIENT RELATIONS DEPARTMENT AT
(800) 847-2424.

C. YOUR SIGNATURE MUST BE GUARANTEED and you MUST complete the signature
guarantee in this Box No. 3 if (i) the value of the Shares tendered
herewith pursuant to the OFFER IS GREATER THAN $100,000, (ii) this LETTER
OF TRANSMITTAL IS SIGNED BY SOMEONE OTHER THAN THE REGISTERED HOLDER OF
THE SHARES TENDERED HEREWITH, or (iii) you REQUEST PAYMENT FOR THE SHARES
TENDERED HEREWITH TO BE SENT TO A PERSON OTHER THAN THE REGISTERED OWNER
of such Shares for the benefit of such owner(s) and/or TO AN ADDRESS
OTHER THAN THE REGISTERED ADDRESS OF THE REGISTERED OWNER of the Shares.
For information with respect to what constitutes an acceptable guarantee,
please see Instruction 4(f).

D. See Instruction 8 and Form W-9 enclosed herewith regarding backup
withholding.

................................ ................................
(SIGNATURE(S) OF OWNER(S) EXACTLY AS REGISTERED)

Dated .........., 20........

DAYTIME TELEPHONE NUMBER( )
................................................

SIGNATURE GUARANTEE (IF APPLICABLE):

.................................................................................
Bank Name

.................................................................................
Print Name of Authorized Signer

Telephone Number ( ) ..................................
(Affix signature guarantee stamp above if
required)
- --------------------------------------------------------------------------------
IF YOUR SHARES ARE HELD IN YOUR OWN NAME, SEND TO: VAN KAMPEN INVESTOR SERVICES
INC., Depositary

DELIVERY TO AN ADDRESS OTHER THAN THAT SHOWN BELOW DOES NOT CONSTITUTE VALID
DELIVERY.

<Table>

FOR ADDITIONAL INFORMATION CALL: (800) 847-2424.
IF YOUR SHARES ARE HELD FOR YOU BY YOUR FINANCIAL ADVISOR, PLEASE CONTACT YOUR
FINANCIAL ADVISOR DIRECTLY.

64 SLT004(b)-9/05
SLTND-9/05

-------------------------------------------------------------------------------
(tear along dotted line)

INSTRUCTIONS
FORMING PART OF THE TERMS AND CONDITIONS OF THE OFFER

1. DELIVERY OF LETTER OF TRANSMITTAL AND CERTIFICATES. This Letter of
Transmittal is to be used only if the Shares to be tendered are registered in
the shareholder's name and the necessary documents will be transmitted to the
Depositary by the shareholder or his broker, dealer or other selling group
member. Do not use this form if a broker, dealer or other selling group member
is the registered owner of the Shares and is effecting the transaction for the
shareholder. A PROPERLY COMPLETED AND DULY EXECUTED LETTER OF TRANSMITTAL OR
MANUALLY SIGNED FACSIMILE OF IT, ANY CERTIFICATES REPRESENTING SHARES TENDERED
AND ANY OTHER DOCUMENTS REQUIRED BY THE LETTER OF TRANSMITTAL SHOULD BE MAILED
OR DELIVERED TO THE DEPOSITARY AT THE ADDRESS SET FORTH IN THE LETTER OF
TRANSMITTAL AND MUST BE RECEIVED BY THE DEPOSITARY ON OR PRIOR TO THE CLOSE OF
THE NEW YORK STOCK EXCHANGE (NORMALLY THE EXCHANGE CLOSES AT 4:00 P.M., EASTERN
TIME, BUT MAY CLOSE EARLIER ON CERTAIN DAYS) ON THE REPURCHASE REQUEST DEADLINE
(OCTOBER 21, 2005, UNLESS EXTENDED).

THE METHOD OF DELIVERY OF ALL DOCUMENTS, INCLUDING CERTIFICATES FOR SHARES,
IS AT THE ELECTION AND RISK OF THE TENDERING SHAREHOLDER. IF DELIVERY IS BY
MAIL, REGISTERED MAIL WITH RETURN RECEIPT REQUESTED, PROPERLY INSURED, IS
RECOMMENDED.

THE FUND WILL NOT ACCEPT ANY ALTERNATIVE, CONDITIONAL OR CONTINGENT
TENDERS. ALL TENDERING SHAREHOLDERS, BY EXECUTION OF THE LETTER OF TRANSMITTAL
(OR A MANUALLY SIGNED FACSIMILE OF IT), WAIVE ANY RIGHT TO RECEIVE ANY NOTICE OF
THE ACCEPTANCE OF THEIR TENDER.

2. COMPLETING THE LETTER OF TRANSMITTAL. If you intend to tender any
Shares pursuant to the Offer, please complete the Letter of Transmittal as
follows:

(a) Read the Letter of Transmittal in its entirety. By signing the
Letter of Transmittal in Box No. 3, you agree to its terms.

(b) Complete Box No. 1 by providing your Social Security Number/Tax
Identification Number, a Confirm Number, if applicable, and selecting
either "Cash" or "Exchange" and selecting and completing Option A, Option B
or Option C.

(c) Complete Box No. 2 if certificates for Shares not tendered or not
purchased and/or any check issued in the name of a person other than the
signer of the Letter of Transmittal are to be sent or wired to someone
other than such signer or to the signer at an address other than that shown
in Box No. 1.

(d) Complete Box No. 3 in accordance with Instruction 4 set forth
below.

3. PARTIAL TENDERS, UNPURCHASED SHARES AND EXCHANGES. If fewer than all of
the Shares evidenced by any certificate submitted are to be tendered and if any
tendered Shares are purchased, new Shares evidenced by your old certificate(s)
will be issued and sent to the registered owner, unless otherwise specified in
Box No. 2 of the Letter of Transmittal, as soon as practicable after the
repurchase request deadline of the Offer.

Tendering shareholders who elect to have the Depositary invest the cash
proceeds from the tender of Shares of the Fund in shares of the same class, in
the case of Class A Shares, Class B Shares of Class C Shares of the Fund, or in
Class A Shares, in the case of Class IB Shares and Class IC Shares of the Fund,
in each case of certain investment companies advised by Van Kampen Asset
Management and distributed by Van Kampen Funds Inc. should select "Exchange" and
select and complete Option A, B or C. The early withdrawal charge will be waived
for Shares tendered for reinvestment pursuant to this election; however, such
shares immediately become subject to a contingent deferred sales charge schedule
equivalent to the early withdrawal charge schedule of the Fund.

4. SIGNATURES ON LETTER OF TRANSMITTAL, AUTHORIZATIONS AND ENDORSEMENTS.

(a) If this Letter of Transmittal is signed by the registered owner(s)
of the Shares tendered hereby, the signature(s) must correspond exactly
with the name(s) in which the Shares are registered.

(b) If the Shares are held of record by two or more joint owners, each
such owner must sign this Letter of Transmittal.

(c) If any tendered Shares are registered in different names, it will
be necessary to complete, sign and submit as many separate Letters of
Transmittal (or manually signed facsimiles of it) as there are different
registrations of Shares.

(d) When this Letter of Transmittal is signed by the registered
owner(s) of the Shares listed and transmitted hereby, no endorsements of
any certificate(s) representing such Shares or separate authorizations are
required. If, however, payment is to be made to a person other than the
registered owner(s), any unpurchased Shares are to be registered in the
name of any person other than the registered owner(s) or any unpurchased
Shares are to be issued to a person other than the registered owner(s),
then the Letter of Transmittal and, if applicable, the certificate(s)
transmitted hereby, must be endorsed or accompanied by appropriate
authorizations, in either case signed exactly as such name(s) appear on the
registration of the Shares and on the face of the certificate(s) and such
endorsements or authorizations must be guaranteed by an institution
described in Box No. 3.

(e) If this Letter of Transmittal or any certificates or
authorizations are signed by trustees, executors, administrators,
guardians, attorneys-in-fact, officers of corporations or others acting in
a fiduciary or representative capacity, such persons should so indicate
when signing and must submit proper evidence satisfactory to the Fund of
their authority so to act. Please contact the Client Relations Department
for assistance at (800) 847-2424.

(f) Your signature MUST be guaranteed and you MUST complete the
signature guarantee in Box No. 3 if (i) the value of the Shares tendered
herewith pursuant to the Offer is greater than $100,000, (ii) this Letter
of Transmittal is signed by someone other than the registered holder of the
Shares tendered herewith or (iii) you request payment for the Shares
tendered herewith to be sent to a payee other than the registered owner of
such Shares and/or to an address other than the registered address of the
registered owner of the Shares. An acceptable guarantee is one made by a
bank or trust company; a broker-dealer; a credit union; a national
securities exchange, registered securities association or clearing agency;
a savings and loan association; or a federal savings bank. The guarantee
must state the words "Signature Guaranteed" along with the name of the
guarantor institution. Shareholders should verify with the institution that
it is an eligible guarantor prior to signing. A signature guarantee may not
be obtained from a notary public.

5. TRANSFER TAXES. The Fund will pay all share transfer taxes, if any,
payable on the transfer to it of Shares purchased pursuant to the Offer. If,
however, (a) payment of the Purchase Price is to be made to any person other
than the registered owner(s), (b) (in the circumstances permitted by the Offer)
unpurchased Shares are to be registered in the name(s) of any person other than
the registered owner(s) or (c) tendered certificates are registered in the
name(s) of any person other than the person(s) signing this Letter of
Transmittal, then the amount of any transfer taxes (whether imposed on the
registered owner(s) or such other persons) payable on account of the transfer to
such person(s) will be deducted from the Purchase Price by the Depositary unless
satisfactory evidence of the payment of such taxes, or exemption therefrom, is
submitted.

6. IRREGULARITIES. All questions as to the validity, form, eligibility
(including time of receipt) and acceptance of any tender of Shares will be
determined by the Fund in its sole discretion, whose determination shall be
final and binding on all parties. The Fund reserves the absolute right to reject
any or all tenders determined by it not to be in appropriate form or the
acceptance of or payment for any Shares which may, in the opinion of the Fund's
counsel, be unlawful. The Fund also reserves the absolute right to waive any of
the conditions of the Offer or any defect or irregularity in tender of any
particular Shares or any particular shareholder, and the Fund's interpretations
of the terms and conditions of the Offer (including these Instructions) will be
final and binding on all parties. Unless waived, any defects or irregularities
in connection with tenders must be cured within such time as the Fund shall
determine. Tendered Shares will not be accepted for payment unless all defects
and irregularities have either been cured within such time or waived by the
Fund. None of the Fund, Van Kampen Funds Inc., the Depositary or any other
person shall be obligated to give notice of defects or irregularities in
tenders, nor shall any of them incur any liability for failure to give any such
notice.

7. QUESTIONS AND REQUESTS FOR ASSISTANCE AND ADDITIONAL COPIES. Questions
and requests for assistance may be directed to, and additional copies of the
Offer and this Letter of Transmittal may be obtained from, Van Kampen Funds
Inc., 1 Parkview Plaza, P.O. Box 5555, Oakbrook Terrace, IL 60181-5555, or by
telephoning (800) 847-2424.

8. BACKUP WITHHOLDING; FORM W-9. Each tendering shareholder who is a United
States person (including a resident alien individual) and who has not already
submitted a completed and signed Form W-9 to the Fund is required to provide the
Depositary with a correct taxpayer identification number ("TIN") on Form W-9
which is enclosed herewith. Failure to furnish a properly completed Form W-9 to
the Depositary may subject the tendering shareholder to backup federal income
tax withholding on the payments made to the shareholder or other payee with
respect to Shares purchased pursuant to the Offer.

9. WITHHOLDING ON NON-U.S. SHAREHOLDERS. The Depositary will withhold
federal income taxes equal to 30% of the gross payments payable to a non-U.S.
shareholder unless the non-U.S. shareholder has provided to the Depositary an
appropriate Form W-8 on which it claims eligibility for a reduced rate of
withholding or establishes an exemption from withholding. For this purpose, a
non-U.S. shareholder is any shareholder that is not (i) a citizen or resident of
the United States, (ii) a corporation or partnership created or organized in or
under the laws of the United States or any state thereof, (iii) an estate the
income of which is subject to United States federal income taxation regardless
of its source or (iv) a trust whose administration is subject to the primary
jurisdiction of a United States court and which has one or more United States
fiduciaries who have authority to control all substantial decisions of the
trust. The Depositary will determine a shareholder's status as a non-U.S.
shareholder and eligibility for a reduced rate of, or an exemption from,
withholding by reference to certificates or statements provided by the non-U.S.
shareholder concerning eligibility for a reduced rate of, or exemption from,
withholding unless facts and circumstances indicate that reliance is not
warranted. A non-U.S. shareholder who has not previously submitted the
appropriate certificates or statements with respect to a reduced rate of, or an
exemption from, withholding for which such shareholder may be eligible should
consider doing so in order to avoid overwithholding. A non-U.S. shareholder may
be eligible to obtain a refund of tax withheld if such shareholder is able to
establish that no tax or a reduced amount of tax was due.

IMPORTANT: THE LETTER OF TRANSMITTAL OR A MANUALLY SIGNED FACSIMILE OF IT
(TOGETHER WITH ANY CERTIFICATES FOR SHARES AND ALL OTHER REQUIRED DOCUMENTS)
MUST BE RECEIVED BY THE DEPOSITARY ON OR BEFORE THE CLOSE OF THE NEW YORK STOCK
EXCHANGE (NORMALLY THE EXCHANGE CLOSES AT 4:00 P.M., EASTERN TIME, BUT MAY CLOSE
EARLIER ON CERTAIN DAYS) ON THE REPURCHASE REQUEST DEADLINE.

64 SLT005-9/05