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                                                                   EXHIBIT 10.23

                                 FIFTH AMENDMENT
                            TO THE ADESA CORPORATION
                     SUPPLEMENTAL EXECUTIVE RETIREMENT PLAN

     WHEREAS, ADESA Corporation, Indianapolis, Indiana (the "Sponsoring
Employer") has adopted the ADESA Corporation Supplemental Executive Retirement
Plan (the "Plan") for the benefit of a select group of management and highly
compensated employees; and

     WHEREAS, pursuant to Section 7.1 of the Plan, the Sponsoring Employer has
reserved the right to amend the Plan by action of its Board of Directors, and
pursuant to such right the Sponsoring Employer has previously amended the Plan:
by a First Amendment, effective in part as of October 1, 2001 and in part as of
November 1, 2001; by a Second Amendment, effective January 1, 2002; by a Third
Amendment, effective January 1, 2003; and by a Fourth Amendment, effective June
1, 2003; and

     WHEREAS, the Board of Directors of the Sponsoring Employer has approved and
adopted the Fifth Amendment to the Plan to provide for the transfer to the Plan
of the account balances under the ALLETE and Affiliated Companies Supplemental
Executive Retirement Plan ("SERP") of those ADESA employees who are participants
in the ALLETE SERP; and

     WHEREAS, the Board of Directors of the Sponsoring Employer has authorized
and directed the President of the Sponsoring Employer to execute the Fifth
Amendment to the Plan;

     NOW, THEREFORE, the Plan is hereby amended, effective January 1, 2004, as
follows:

          I.   Article II is amended by the addition of a new section 2.3 which
               shall read in its entirety as follows:

               "2.3  TRANSFERS FROM ALLETE SERP. The provisions of this section
          shall govern the transfer from the ALLETE Supplemental Executive
          Retirement Plan ("ALLETE SERP") to the ADESA Corporation Supplemental
          Executive Retirement Plan (the "ADESA SERP" or "Plan") of the benefits
          accrued by employees of ADESA Corporation who are eligible
          participants under the ALLETE SERP.

               (a)   The provisions of this section shall be applicable only to
                     the extent that the Plan Administrator has determined, to
                     its satisfaction, that the ALLETE SERP has been amended to
                     provide for such transfers.

               (b)   In the case of any employee of ADESA Corporation who is an
                     eligible participant under both the ALLETE SERP and the
                     ADESA SERP at the time of such transfer, the amount
                     transferred from the ALLETE SERP shall be credited by the
                     Plan Administrator as

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                     soon as administratively feasible to such employee's
                     Deferred Account or Employer Contribution Account, or both,
                     as applicable, under the Plan. Thereafter such amounts
                     shall be invested, re-invested, credited with investment
                     gains and losses and distributed in accordance with, and
                     shall otherwise be subject to, the applicable provisions of
                     this Plan, including any amendments thereto adopted
                     subsequent to such transfer.

               (c)   In the case of any employee of ADESA Corporation who is an
                     eligible participant under the ALLETE SERP, but who is not
                     an eligible participant under ADESA SERP, at the time of
                     such transfer, the amount transferred from the ALLETE SERP
                     shall be credited by the Plan Administrator as soon as
                     administratively feasible to a Deferral Account which the
                     Administrator shall establish on behalf of such employee
                     under the Plan for the sole purpose of effecting such
                     transfer. Thereafter such Deferral Account shall be treated
                     as an inactive Participant account as set forth in, and as
                     limited by, the provisions of Section 2.2. Thereafter such
                     amounts shall also be invested, re-invested, credited with
                     investment gains and losses and distributed in accordance
                     with, and shall otherwise be subject to, the applicable
                     provisions of this Plan, including any amendments thereto
                     adopted subsequent to such transfer.

               (d)   No transfer described in (b) or (c) above may be accepted
                     by the Plan Administrator until after that portion of the
                     2003 bonus which the ALLETE SERP participant has elected to
                     defer into the ALLETE SERP has been credited to his or her
                     deferral account under the ALLETE SERP.

               (e)   In the case of any transfer described in (b) or (c) above,
                     to the extent that the amount to be transferred from the
                     ALLETE SERP consists of mutual fund investments, the
                     administrator of the ALLETE SERP shall sell such
                     investments and wire transfer the liquidation proceeds to
                     the Plan Administrator. Upon receipt of same the Plan
                     Administrator shall deposit, as soon as administratively
                     feasible, such funds, in cash into the ADESA Corporation
                     Supplemental Executive Retirement Plan Trust (the "ADESA
                     SERP Rabbi Trust").

               (f)   In the case of any transfer described in (b) or (c) above,
                     to the extent that the amount to be transferred from the
                     ALLETE SERP consists of the balance in the employee's
                     Company Fixed Fund under the ALLETE SERP, ADESA Corporation
                     shall contribute such balance, including interest
                     calculated to the date of withdrawal from the ALLETE SERP
                     at the rate set forth therein, as

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                     soon as administratively feasible in cash into the ADESA
                     SERP Rabbi Trust.

               (g)   For purposes of the allocation and subsequent investment of
                     the contributions described in (e) and (f) above, the Plan
                     Administrator shall provide the trustee of the ADESA SERP
                     Rabbi Trust a per employee allocation of such
                     contributions. In addition, the Plan Administrator shall
                     obtain from each such employee a directed investment
                     election form, and forward a copy of same to such trustee,
                     pursuant to which such contributions shall thereafter be
                     invested and reinvested by such trustee at the direction of
                     the employee, including all subsequent changes in such
                     investment direction by the employee."

     II.  Section 5.1, as previously amended by the Third Amendment effective
          January 1, 2003, is hereby amended in its entirety to read as follows:

          "5.1  TIME OF PAYMENT OF BENEFITS. All amounts credited to the
     Deferral and Employer Contribution Accounts of an active or inactive
     Participant shall be, or shall commence to be, distributed to or for the
     benefit of such Participant (or his or her designated beneficiary in the
     event of the Participant's death) within a reasonable period following the
     earliest of: (i) the date, prior to cessation of ADESA Corporation as an
     affiliate of ALLETE, as of which the Participant terminates employment with
     ALLETE, Inc. and all of its affiliated companies; (ii) the date, on or
     after cessation of ADESA Corporation as an affiliate of ALLETE, as of which
     the Participant terminates employment with ADESA Corporation and all of its
     affiliated companies; or (iii) the effective date of any Change in Control
     of the Company."

     IN WITNESS WHEREOF, the President of the Sponsoring Employer has caused
this Fifth Amendment to be executed this 17th day of December, 2003, but
effective as of January 1, 2004.

                                             ADESA CORPORATION


                                             By:  /s/ James P. Hallett
                                                --------------------------------
                                                James P. Hallett, President

ATTEST:

 /s/ Karen C. Turner
----------------------------------
Karen C. Turner, Secretary