EXHIBIT 99.3



                        CERTIFICATION OF PERIODIC REPORT

I, Elizabeth S. Acton of Comerica Incorporated (the "Company"), certify,
pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, 18 U.S.C. Section
1350, that:

(1)   The Annual Report on Form 10-K of the Company for the year ended December
      31, 2002 (the "Report") fully complies with the requirements of Section
      13(a) or 15(d) of the Securities Exchange Act of 1934 (15 U.S.C. 78m or
      78o(d)); and

(2)   the information contained in the Report fairly presents, in all material
      respects, the financial condition and results of operations of the
      Company.

Dated: March 25, 2003

                                                      /s/ Elizabeth S. Acton
                                                     ---------------------------
                                                     Elizabeth S. Acton
                                                     Executive Vice President
                                                     and Chief Financial Officer





A signed original of this written statement required by Section 906 has been
provided to Comerica Incorporated and will be retained by Comerica Incorporated
and furnished to the Securities and Exchange Commission or its staff upon
request.