SECURITIES EXCHANGE COMMISSION


                              Washington, DC 20549

                    Under the Securities Exchange Act of 1934

                           WABASH NATIONAL CORPORATION
                                (Name of Issuer)

                                     Common
                         (Title of Class of Securities)


              Date of Event Which Requires Filing of this Statement
                                 August 15, 2003

                 Check the appropriate box to designate the rule
                    pursuant to which this Schedule is filed


                                [ ] Rule 13d-1(b)
                                [X] Rule 13d-1(c)
                                [ ] Rule 13d-1(d)


                                     929566107


                                 (CUSIP NUMBER)















1)       Name of Reporting Pioneer Global Asset Person Management S.p.A.


         IRS Identification                      98-0362802
         No. of Above

2)       Check the Appropriate Box               (a)
         of A Member of  Group
         (See Instructions)                      (b)

3)       SEC Use Only

4)       Citizenship of Place of
         Organization                            Italy

         Number of                               (5) Sole Voting     2,083,332
         Shares                                  Power
         Beneficially Owned                      (6) Shared Voting   0
         by Each Reporting                       Power
         Person With                             (7) Sole Disposi-
                                                 tive Power          2,083,332
                                                 (8) Shared Disposi-
                                                 tive Power          0

9)       Aggregate Amount Beneficially           2,083,332
         Owned by Each
         Reporting Person

10)      Check if the aggregate
         Amount in Row  (9) Exclude Certain
         Shares (See
         Instructions)

11)      Percent of Class Represented
         By Amount in Row 9.                     8.12%

12)      Type of Reporting
         Person (See Instructions)               IA











Item 1(a)         Name of Issuer.

                  WABASH NATIONAL CORPORATION

Item 1(b)         Address of Issuer's Principal Executive Offices:

                  1000 Sagamore Parkway South
                  Lafayette, IN 47905

Item 2(a)         Name of Person Filing:

                  Pioneer Global Asset Management S.p.A.

Item 2(b)         Address of Principal Business Office:

                  Galleria San Carlo 6,
                  20122 Milan, Italy

Item 2(c)         Citizenship:

                  Italy

Item 2(d)         Title of Class of Securities:

                  Common Stock

Item 2(e)         CUSIP Number:

                  929566107

Item 3            The person filing this statement pursuant to Rule 13d-1(b)
                  or 13d-2(b) is:

                  (Inapplicable)







Item 4.  Ownership.

                 (a) Amount Beneficially Owned: 2,083,332

                 (b) Percent of Class: 8.12%

                 (c) Number of shares as to which such person has

                       (i)  sole power to vote or to direct the vote: 2,083,332

                       (ii) shared power to vote or to direct vote:    0

                       (iii) sole power to dispose or to direct
                             disposition of:                          2,083,332

                       (iv) shared power to dispose or to direct
                            disposition                                 0

Item 5.  Ownership of Five Percent or Less of a Class.

         If this statement is being filed to report the fact that as
         of the date Hereof the reporting person has ceased to be the
         beneficial owner of more than five percent of the class of
         securities, check here:


Item 6.  Ownership of More than Five Percent on Behalf of Another Person.

         Inapplicable.

Item 7.  Identification and Classification of the Subsidiary Which Acquired
         the Security Being Reported On By the Parent Holding Company.

         Inapplicable.

Item 8.  Identification and Classification of Members of the Group.

         Inapplicable.

Item 9.  Notice of Dissolution of the Group.

         Inapplicable.







Item 10. Certification.

By signing below I certify that, to the best of my knowledge and belief, the
securities referred to above were acquired in the ordinary course of business
and were not acquired for the purpose of and do not have the effect of changing
or influencing the control of the issuer of such securities and were not
acquired in connection with or as a participant in any transactions having such
purposes or effect.

After reasonable inquiry and to the best of my knowledge and believe, I certify
that the information set forth in this statement is true, complete and correct.


     August 15, 2003
     Date




     /s/Dario Frigerio
     Name: Dario Frigerio
     Title: Chief Executive Officer