SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                   SCHEDULE TO

            TENDER OFFER STATEMENT UNDER SECTION 14(D)(1) OR 13(E)(1)
                     OF THE SECURITIES EXCHANGE ACT OF 1934
                                (AMENDMENT NO. 4)

                     --------------------------------------
                          OFFICIAL PAYMENTS CORPORATION
                       (Name of Subject Company (Issuer))

                        KINGFISH ACQUISITION CORPORATION
              a wholly-owned subsidiary of Tier Technologies, Inc.
                                       and
                             TIER TECHNOLOGIES, INC.
                      (Names of Filing Persons (Offerors))

                     --------------------------------------

                     COMMON STOCK, PAR VALUE $.01 PER SHARE
                         (Title of Class of Securities)

                     --------------------------------------

                                   676235 10 4
                      (CUSIP Number of Class of Securities)

                     --------------------------------------

                                JAMES L. BILDNER
                             TIER TECHNOLOGIES, INC.
                           1350 TREAT BLVD., SUITE 250
                             WALNUT CREEK, CA 94596
                            TELEPHONE: (925) 937-3950
                            FACSIMILE: (925) 937-3752

         (Name, address, and telephone numbers of person authorized to
        receive notices and communications on behalf of filing persons)

                                   Copies to:

                              BRUCE R. DEMING, ESQ.
                              JACK G. MARTEL, ESQ.
                           FARELLA BRAUN + MARTEL LLP
                        235 MONTGOMERY STREET, 30TH FLOOR
                             SAN FRANCISCO, CA 94104
                            TELEPHONE: (415) 954-4400
                            FACSIMILE: (415) 954-4480

                            Calculation of Filing Fee

----------------------------------------------------------------------------
Transaction valuation $86,154,144*      Amount of filing fee $17,231
----------------------------------------------------------------------------

*    For purposes of calculating the filing fee only. The filing fee calculation
     assumes the purchase of all outstanding shares of common stock, par value
     $0.01 per share, as well as the exercise of all exercisable and outstanding
     stock options, of Official Payments Corporation at a price of $3.00 per
     share, without interest. As of June 6, 2002, there were 22,952,876 shares
     issued and outstanding and 5,765,172 shares underlying stock options. Based
     on the foregoing, the transaction value is equal to the product of
     28,718,048 shares and $3.00 per share. The amount of the filing fee
     calculated in accordance with Rule 0-11 of the Securities Exchange Act of
     1934, as amended, equals 1/50th of one percent of the value of the
     transaction.

[X]  Check the box if any part of the fee is offset as provided by Rule
     0-11(a)(2) and identify the filing with which the offsetting fee was
     previously paid. Identify the previous filing by registration statement
     number, or the Form or Schedule and the date of its filing.

          Amount Previously Paid: $17,231

          Form or Registration No.: Schedule TO-T/A

          Filing Party: Tier Technologies, Inc.

          Date Filed: June 20, 2002

[ ]  Check the box if the filing relates solely to preliminary communications
     made before the commencement of a tender offer.

     Check the appropriate boxes below to designate any transactions to which
     the statement relates:
     [X]  third-party tender offer subject to Rule 14d-1.
     [ ]  issuer tender offer subject to Rule 13e-4.
     [ ]  going-private transaction subject to Rule 13e-3.
     [ ]  amendment to Schedule 13D under Rule 13d-2.

     Check the following box if the filing is a final amendment reporting the
     results of the tender offer: [ ]


                                   SCHEDULE TO

     This Amendment No. 4 amends and supplements the Tender Offer Statement, as
amended, on Schedule TO ("Schedule TO") filed with the Securities and Exchange
Commission on June 11, 2002, relating to a tender offer by Kingfish Acquisition
Corporation, a Delaware corporation (the "Purchaser") and a wholly-owned
subsidiary of Tier Technologies, Inc., a California corporation ("Parent"), to
purchase all of the outstanding shares of common stock, par value $0.01 per
share (the "Shares"), of Official Payments Corporation, a Delaware corporation
(the "Company"), at a price of $3.00 per Share, net to the seller in cash,
without interest thereon, upon the terms and subject to the conditions set forth
in the Offer to Purchase, dated June 11, 2002 and in the related Letter of
Transmittal (which, together with any supplements or amendments, collectively
constitute the "Offer"). Capitalized terms used and not otherwise defined shall
have the meanings assigned to such terms in the Offer to Purchase.

Items 1, 4 and 11.

     Items 1, 4 and 11 of the Schedule TO are hereby amended and supplemented to
add the following:

     On July 10, 2002, Purchaser issued (1) a press release announcing the
extension of the Expiration Date until 5:00 p.m., New York City time, on
Wednesday, July 24, 2002 and (2) a press release announcing the status of the
tender offer. The Offer was previously scheduled to expire at 12:00 midnight,
New York City time, on Tuesday, July 9, 2002. The press releases are attached as
Exhibit (a)(5)(E) and Exhibit (a)(5)(F) to this Amendment No. 4 on Schedule TO
and incorporated by reference herein.

Item 12. Exhibits

         (a)(1)(A)        Offer to Purchase, dated February 25, 2000.

         (a)(1)(B)        Letter of Transmittal.

         (a)(1)(C)        Notice of Guaranteed Delivery.

         (a)(1)(D)        Form of letter to clients for use by Brokers, Dealers,
                          Commercial Banks, Trust Companies and Nominees.

         (a)(1)(E)        Form of letter to Brokers, Dealers, Commercial Banks,
                          Trust Companies and Other Nominees.

         (a)(1)(F)        Guidelines for Certification of Taxpayer
                          Identification Number on Substitute Form W-9.

         (a)(1)(G)        Press release issued by Parent and Purchaser, dated
                          June 11, 2002, announcing the commencement of the
                          Offer.

         (a)(1)(H)        Summary Advertisement, dated June 11, 2002, appearing
                          in the Wall Street Journal.

         (a)(5)(A)        Press release issued by Parent, dated June 17, 2002,
                          announcing termination of the waiting period under the
                          Hart-Scott-Rodino Act.

         (a)(5)(B)        Press release issued by Parent, dated June 20, 2002,
                          regarding extension of the Offer until 12:00 midnight,
                          New York City time, on July 9, 2002.

         (a)(5)(C)        Complaint of Roti v. Official Payments Corporation, et
                          al., filed in the Court of Chancery of the State of
                          Delaware on June 19, 2002.

         (a)(5)(D)        Memorandum of Understanding, dated June 26, 2002,
                          between the parties to the Complaint.

         (a)(5)(E)        Press release issued by Parent, dated July 10, 2002,
                          regarding extension of the Offer until 5:00 p.m., New
                          York City time, on July 24, 2002.

         (a)(5)(F)        Press release issued by Parent, dated July 10, 2002,
                          regarding status of the Offer.

         (b)              Not applicable.


         (d)(1)           Agreement and Plan of Merger, dated as of May 30,
                          2002, by and among Parent, Purchaser and the Company.

         (d)(2)           Stockholders Agreement, dated as of May 30, 2002, by
                          and among Parent, Purchaser and the holders of Shares
                          parties thereto.

         (d)(3)           Confidentiality Agreement, dated April 17, 2002, by
                          and between Parent and the Company.

         (d)(4)           Form of Employment Agreement.

         (g)              Not applicable.

         (h)              Not applicable.


Signature. After due inquiry and to the best of their knowledge and belief, the
undersigned certify that the information set forth in this statement is true,
complete and correct.

                                   KINGFISH ACQUISITION CORPORATION


                                   By: /s/ James L. Bildner
                                       ------------------------------
                                   Name: James L. Bildner
                                   Title: President and Chief Executive Officer
                                   Date: July 10, 2002

                                   TIER TECHNOLOGIES, INC.


                                   By: /s/ James L. Bildner
                                       ------------------------------
                                   Name: James L. Bildner
                                   Title: Chairman and Chief Executive Officer
                                   Date: July 10, 2002



EXHIBIT INDEX

EXHIBIT NO.   DESCRIPTION

(a)(1)(A)     Offer to Purchase, dated June 11, 2002.*

(a)(1)(B)     Letter of Transmittal.*

(a)(1)(C)     Notice of Guaranteed Delivery.*

(a)(1)(D)     Form of letter to clients for use by Brokers, Dealers, Commercial
              Banks, Trust Companies and Nominees.*

(a)(1)(E)     Form of letter to Brokers, Dealers, Commercial Banks, Trust
              Companies and Nominees.*

(a)(1)(F)     Guidelines for Certification of Taxpayer Identification Number on
              Substitute Form W-9.*

(a)(1)(G)     Press release issued by Parent and Purchaser, dated June 11, 2002,
              announcing the commencement of the Offer.*

(a)(1)(H)     Summary Advertisement, dated June 11, 2002, appearing in the Wall
              Street Journal.*

(a)(5)(A)     Press release issued by Parent, dated June 17, 2002, announcing
              termination of the waiting period under the Hart-Scott-Rodino
              Act.*

(a)(5)(B)     Press release issued by Parent, dated June 20, 2002, regarding
              extension of the Offer until 12:00 midnight, New York City time,
              on July 9, 2002.*

(a)(5)(C)     Complaint of Roti v. Official Payments Corporation, et al. filed
              in the Court of Chancery of the State of Delaware on June 19,
              2002.*

(a)(5)(D)     Memorandum of Understanding, dated June 26, 2002, between the
              parties to the Complaint.*

(a)(5)(E)     Press release issued by Parent, dated July 10, 2002, regarding
              extension of the Offer until 5:00 p.m., New York City time, on
              July 24, 2002.

(a)(5)(F)     Press release issued by Parent, dated July 10, 2002, regarding
              status of the Offer.

(d)(1)        Agreement and Plan of Merger, dated as of May 30, 2002, by and
              among Parent, Purchaser and the Company.*

(d)(2)        Stockholders Agreement, dated as of May 30, 2002, by and among
              Parent, Purchaser and the holders of Shares parties thereto.*

(d)(3)        Confidentiality Agreement, dated April 17, 2002, by and between
              Parent and the Company.*

(d)(4)        Form of Employment Agreement.*


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* Previously filed.