<PAGE>

                                                                    EXHIBIT 99.4

                        MONTHLY SERVICER'S CERTIFICATE
                             FIRST USA BANK, N.A.


                       BANC ONE CREDIT CARD MASTER TRUST
                                 SERIES 1995-B


               The undersigned, a duly authorized representative of First USA
Bank N.A., as Servicer ("First USA"), pursuant to the Pooling and Servicing
Agreement dated as of November 1, 1994 (as amended and supplemented, the
"Agreement"), as supplemented by the Series 1995-B Supplement (as amended and
supplemented, the "Series Supplement"), between First USA, as Seller and
Servicer, and Bankers Trust Company, as Trustee, does hereby certify as follows:

          1.  Capitalized terms used in this Certificate have their respective
     meanings as set forth in the Agreement or Series Supplement, as applicable.

          2.  First USA is, as of the date hereof, the Servicer under the
     Agreement.

          3.  The undersigned is a Servicing Officer.

          4.  This Certificate relates to the Distribution Date occuring on
     15-Sep-00.
     ----------

          5.  As of the date hereof, to the best knowledge of the undersigned,
     the Servicer has performed in all material respects all its obligations
     under the Agreement through the Monthly Period preceding such Distribution
     Date. [Or if there has been a default in the performance of any such
     obligation, set forth in detail the (i) nature of such default, (ii) the
     action taken by the Seller and Servicer, if any, to remedy such default and
     (iii) the current status of each such default.].

          6.  As of the date hereof, to the best knowledge of the undersigned,
     no Pay Out Event occurred on or prior to such Distribution Date.

          7.  As of the date hereof, to the best knowledge of the undersigned,
     no Lien has been placed on any of the Receivables other pursuant to the
     Agreement. [or, if there is a Lien, such Lien consists of ]

              IN WITNESS WHEREOF, the undersigned has duly executed and
delivered this Certificate this 11th         day of       Sep-00
                                ----------          ------------


              FIRST USA BANK, N.A.
              as Servicer

              By:  /s/ Tracie Klein
                   -----------------------------------------------------
                   Name:    Tracie  Klein
                   Title:   First Vice President
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                         MONTHLY SERVICER'S CERTIFICATE
                              FIRST USA BANK, N.A.


                        BANC ONE CREDIT CARD MASTER TRUST
                                  SERIES 1996-A


               The undersigned, a duly authorized representative of First USA
Bank, NA, as Servicer ("First USA"), pursuant to the Pooling and Servicing
Agreement dated as of November 1, 1994 (as amended and supplemented, the
"Agreement"), as supplemented by the Series 1996-A Supplement dated as of March
27, 1996 (as amended and supplemented, the "Series Supplement"), between First
USA, as Seller and Servicer, and Bankers Trust Company, as Trustee, does hereby
certify as follows:

          1.  Capitalized terms used in this Certificate have their respective
     meanings as set forth in the Agreement or Series Supplement, as applicable.

          2.  First USA is, as of the date hereof, the Servicer under the
     Agreement.

          3.  The undersigned is a Servicing Officer.

          4.  This Certificate relates to the Distribution Date occuring on
     15-Sep-00.
     ---------

          5.  As of the date hereof, to the best knowledge of the undersigned,
the Servicer has performed in all material respects all its obligations under
the Agreement through the Monthly Period preceding such Distribution Date. [Or
if there has been a default in the performance of any such obligation, set forth
in detail the (i) nature of such default, (ii) the action taken by the Seller
and Servicer, if any, to remedy such default and (iii) the current status of
each such default; if applicable].

          6.   As of the date hereof, to the best knowledge of the undersigned,
no Pay Out Event occurred on or prior to such Distribution Date.

          7.   As of the date hereof, to the best knowledge of the undersigned,
no Lien has been placed on any of the Receivables other than pursuant to the
Agreement. [or, if there is a Lien, such Lien consists of]

               IN WITNESS WHEREOF, the undersigned has duly executed and
delivered this Certificate this 11th day of Sep-00
                                ----        ------


              FIRST USA BANK, N.A.
              as Servicer

              By:  /s/ Tracie Klein
                   -----------------------------------------------------
                   Name:    Tracie  Klein
                   Title:   First Vice President