<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
             16-Oct-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  10th             day of             Oct-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
                 16-Oct-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   10th           day of           Oct-00
                                  -------------          ---------------


          FIRST USA BANK, N.A.
          as Servicer


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