<PAGE>

                                                                    Exhibit 10.3

                      Board of Trade Clearing Corporation
                    141 West Jackson Boulevard - Suite 1460
                            Chicago, Illinois 60604


                                April 18, 2000


Personal Delivery
-----------------

Mr. David Brennan
Chairman, Board of Directors
Chicago Board of Trade
141 West Jackson Boulevard
Chicago, Illinois 60604

          Re:  Reimbursement Agreement
               -----------------------
Dear David:

     This letter confirms the agreement between the Board of Trade of the City
of Chicago (the "CBOT") and the Board of Trade Clearing Corporation ("BOTCC")
concerning the appointment of Mr. Dennis Dutterer as Interim President & Chief
Executive Officer of the CBOT. For good and valuable consideration, the CBOT and
BOTCC agree as follows:

     1.  Mr. Dutterer shall continue to serve as President & Chief Executive
Officer of BOTCC pursuant to the terms of his Employment Agreement with BOTCC,
as amended. It is understood and agreed by the parties that, during such period
as Mr. Dutterer shall serve as Interim President & Chief Executive Officer of
the CBOT, Mr. Dutterer shall devote substantial amounts of his time and
attention to his duties and responsibilities at the CBOT associated with such
appointment.

     2.  Mr. Dutterer shall serve as the Interim President and Chief Executive
Officer of the CBOT pursuant to the terms and conditions of the letter agreement
between Mr. Dutterer and the CBOT dated April 18, 2000.

     3.  Mr. Dutterer's compensation for serving both BOTCC and the CBOT shall
be paid to him by BOTCC, with CBOT reimbursing BOTCC for not only his
compensation for services to the CBOT under the letter agreement between Mr.
Dutterer and the CBOT dated April 18, 2000, but also any applicable employment
taxes (and any gross-ups therefor). For so long as Mr. Dutterer is interim
President and/or Chief Executive Officer of the CBOT, BOTCC and the CBOT agree
that his base salary, on an annualized basis, shall be $825,000. Other than as
expressly set forth in the letter agreement between Mr. Dutterer and the CBOT
dated April 18, 2000, any and all other costs and expenses associated with Mr.
Dutterer's employment with the CBOT and/or BOTCC (including, but not limited to
the costs and expenses associated with all of his employee benefits) shall be
borne solely by BOTCC and shall not be subject to reimbursement by the CBOT.
Mr. Dutterer shall continue to be eligible for discretionary bonuses for his
services to BOTCC under his Employment Agreement, for which BOTCC shall be
solely responsible. Any and all bonuses awarded to Mr. Dutterer for his services
to BOTCC and the CBOT shall be paid to him by BOTCC, provided, however, that
the CBOT shall be responsible for reimbursing BOTCC for the amount of any bonus
<PAGE>

Mr. David Brennan                     -2-                         April 18, 2000


the CBOT, in its sole and absolute discretion (as shall be determined by the
Board of Directors of the CBOT), awards to Mr. Dutterer, plus any applicable
employment taxes (and any gross-ups therefor) that BOTCC would be required to
pay. The CBOT shall make all reimbursement payments to BOTCC for the benefit of
Mr. Dutterer at least three (3) business days prior to the scheduled payment
date or other payment date on which BOTCC is obligated to pay Mr. Dutterer for
any salary or bonuses for which CBOT is responsible under this letter agreement;
provided that the CBOT receives reasonable prior notice of such payment dates.

     The parties certify that they have read this letter agreement in its
entirety, that they understand the term of this letter agreement and understand
that such terms are legally enforceable, that they have had ample opportunity
to negotiate with each other with regard to all of its terms, that they have
entered into this letter agreement freely and voluntarily, that they intend to
and shall be legally bound by this letter agreement, and that they have full
power, right, authority, and competence to enter into and execute this letter
agreement. This letter agreement shall be governed by, and construed in
accordance with, the internal laws of the State of Illinois (without giving
effect to the principles of conflicts of laws thereof). Each of the parties
hereto hereby consents to personal jurisdiction in, and agrees that venue for
any action to enforce the provisions of this letter agreement shall be properly
laid in, any federal or state court located in Cook County in the State of
Illinois. This letter agreement is intended to bind and inure to the benefit of
and be enforceable by each of the parties and its respective successors and
assigns. The provisions hereof may be amended or waived only with the prior
written consent of each of the parties hereto in each case, as determined by the
Board of Directors of such entity in its sole and absolute discretion.

     Please acknowledge your acceptance of and concurrence with this letter
agreement by signing and dating the enclosed duplicate original of this letter
agreement below and returning it to me. This original of the letter agreement,
which I have already signed on behalf of BOTCC, is for you. We look forward to
continuing a mutually beneficial relationship with you.


                            BOARD OF TRADE CLEARING CORPORATION

                               /s/ William C. Floersch
                            By:_________________________________________________
                               William C. Floersch, Chairman, Board of Governors


Accepted and Agreed
as of the 18th day of April, 2000.

BOARD OF TRADE OF THE CITY OF CHICAGO

   /s/ David Brennan
By:___________________________________________
   David Brennan, Chairman, Board of Directors