As filed with the Securities and Exchange Commission on February 26, 1999.

                                             Registration No. 333-____________


                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                    FORM S-8

                             Registration Statement
                                      Under
                           The Securities Act of 1933

                      TRANSACTION SYSTEMS ARCHITECTS, INC.
             (Exact name of registrant as specified in its charter)

                               Delaware 47-0772104
        (State or other jurisdiction (I.R.S. Employer Identification No.)
                        of incorporation or organization)

                             224 South 108th Avenue
                              Omaha, Nebraska 68154
               (Address of principal executive offices) (Zip Code)

           Transaction Systems Architects, Inc. 1999 Stock Option Plan
     Transaction Systems Architects, Inc. 1999 Employee Stock Purchase Plan
                            (Full title of the plans)

                              David P. Stokes, Esq.
                          General Counsel and Secretary
                      Transaction Systems Architects, Inc.
                             224 South 108th Avenue
                              Omaha, Nebraska 68514
                                 (402) 334-5101
(Name, address and telephone number, including area code, of agent for service)

CALCULATION OF REGISTRATION FEE ================================== ========================== ===================== ================ =============== Proposed Maximum Proposed Amount of Title of Securities to be Amount to be Offering Price Per Maximum Registration Registered Registered(1) Share Aggregate Fee Offering Price ================================== ========================== ===================== ================ =============== 1999 STOCK OPTION PLAN 1,000,000 shares $ 39.8125 (2) $ 39,812,500 $ 11,067.88 Class A Common Stock, $0.005 par value - ---------------------------------- -------------------------- --------------------- ---------------- --------------- 1999 EMPLOYEE STOCK 250,000 shares $ 39.8125 (2) $ 9,953,125 $ 2,766.97 PURCHASE PLAN Class A Common Stock, $0.005 par value ================================== ========================== ===================== ================ =============== TOTAL 1,250,000 shares $ 49,765,625 $ 13,834.84 ================================== ========================== ===================== ================ ===============
(1) Pursuant to Rule 416, this Registration Statement also covers any additional shares of Class A Common Stock which may be issuable pursuant to the antidilution provisions of the Transaction Systems Architects, Inc. 1999 Stock Option Plan or Transaction Systems Architects, Inc. 1999 Employee Stock Purchase Plan. (2) Estimated solely for purposes of calculating the registration fee pursuant to Rule 457(h). The price is based upon the average of the high and low prices of Transaction Systems Architects, Inc. Class A Common Stock on February 22, 1999, as reported on the National Association of Securities Dealers Automated Quotations system. PART II INFORMATION REQUIRED IN THE REGISTRATION STATEMENT Item 3. Incorporation of Certain Documents by Reference The documents listed in (a) through (c) below are incorporated by reference in this registration statement and all documents subsequently filed by the registrant pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), prior to the filing of a post-effective amendment which indicates that all securities offered have been sold or which deregisters all securities then remaining unsold, shall be deemed to be incorporated by reference in the registration statement and to be part thereof from the date of filing of such documents. (a) The registrant's latest annual report filed pursuant to section 13(a) or 15(d) of the Exchange Act. (b) All other reports filed pursuant to Section 13(a) or 15(d) of the Exchange Act since the end of the fiscal year covered by the registrant document referred to in (a) above. (c) The description of the class of securities contained in a registration statement filed under the Exchange Act, including any amendment or report filed for the purpose of updating such description. Item 6. Indemnification of Directors and Officers. Section 145 of the Delaware General Corporation Law provides for the indemnification of officers and directors, subject to certain limitations. The Certificate of Incorporation of the registrant expressly provides for indemnification of an officer or director made a party or threatened to be made a party to proceedings by reason of the fact that such person was an officer or director. The Certificate of Incorporation also authorizes the registrant to maintain officer and director liability insurance, and such a policy is currently in effect. Item 8. Exhibits Exhibit Number 5 Opinion of Legal Counsel 23 Consent of Arthur Andersen LLP 24 Power of Attorney (included in Signature Page) Item 9. Undertakings. (a) The undersigned registrant hereby undertakes: 1. To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement: (i) To include any prospectus required by Section 10(a)(3) of the Act; (ii) To reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement. Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the Commission pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than a 20% change in the maximum aggregate offering price set forth in the "Calculation of Registration Fee" table in the effective registration statement. (iii) To include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change to such information in the registration statement; Provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in periodic reports filed by the registrant pursuant to Section 13 or Section 15(d) of the Exchange Act that are incorporated by reference in this registration statement. 2. That, for the purpose of determining any liability under the Act, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof. 3. To remove from registration by means of post- effective amendment any of the securities being registered which remain unsold at the termination of the offering. (b) The undersigned registrant hereby undertakes that, for purposes of determining any liability under the Act, each filing of the registrant's annual report pursuant to Section 13(a) or Section 15(d) of the Exchange Act (and, where applicable, each filing of an employee benefit plan's annual report pursuant to Section 15(d) of the Exchange Act) that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof. (c) Insofar as indemnification for liabilities arising under the Act may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer, or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Act and will be governed by the final adjudication of such issue. SIGNATURES The Registrant. Pursuant to the requirements of the Securities Act of 1933, the registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Omaha, State of Nebraska, on this 26th day of February, 1999. TRANSACTION SYSTEMS ARCHITECTS, INC. By: /s/ William E. Fisher --------------------------------- William E. Fisher, Chief Executive Officer,President and Director POWER OF ATTORNEY We, the undersigned officers and directors of Transaction Systems Architects, Inc., hereby severally and individually constitute and appoint William E. Fisher, Gregory J. Duman, and Dwight G. Hanson, and each of them, the true and lawful attorneys and agents of each of us to execute in the name, place and stead of each of us (individually and in any capacity stated below) any and all amendments to this Registration Statement on Form S-8, and all instruments necessary or advisable in connection therewith, and to file the same with the Securities and Exchange Commission, each of said attorneys and agents to have power to act with or without the other and to have full power and authority to do and perform in the name and on behalf of each of the undersigned every act whatsoever necessary or advisable to be done in the premises as fully and to all intents and purposes as any of the undersigned might or could do in person, and we hereby ratify and confirm our signatures as they may be signed by our said attorneys and agents and each of them to any and all such amendments and other instruments. Pursuant to the requirements of the Securities Act of 1933, this Registration Statement has been signed by the following persons in the capacities and on the date indicated.
Name Title Date - ------------------------ --------------------------------- ------- /s/ William E. Fisher Chief Executive Officer, President February 26, 1999 William E. Fisher and Director (Principal Executive Officer) /s/ Gregory J. Duman Chief Financial Officer February 26, 1999 Gregory J. Duman (Principal Financial Officer) /s/ Dwight G. Hanson Vice President February 26, 1999 Dwight G. Hanson (Principal Accounting Officer) /s/ David C. Russell Director February 26, 1999 David C. Russell /s/ Promod Haque Director February 26, 1999 Promod Haque /s/ Charles E. Noell, III Director February 26, 1999 Charles E. Noell, III /s/ Jim D. Kever Director February 26, 1999 Jim D. Kever /s/ Larry G. Fendley Director February 26, 1999 Larry G. Fendley
EXHIBIT INDEX Exhibit Number Description - --------------- ------------- 5 Opinion of Legal Counsel 23 Consent of Arthur Andersen LLP 24 Power of Attorney (included in Signature Page)
                                BAKER & McKENZIE
                                Attorneys at Law

                              One Prudential Plaza
                             130 East Randolph Drive
                             Chicago, Illinois 60601


                                February 26, 1999

Board of Directors
Transaction Systems Architects, Inc.
224 South 108th Avenue
Omaha, Nebraska  68154

Re:      Transaction Systems Architects, Inc. (the "Company")

Gentlemen:

         We have acted as your counsel in connection with the  registration,  on
a Registration  Statement on Form S-8 (the  "Registration  Statement") under the
Securities Act of 1933, as amended,  of an aggregate of 1,250,000  shares of the
Company's  Class A Common  Stock,  $.005 par value per share (the "Stock") to be
issued by the  Company  pursuant  to the  Company's  1999 Stock  Option Plan and
1999 Employee  Stock  Purchase Plan  (together,  the "Plans").  We have reviewed
the Registration  Statement,  the charter and by-laws of the Company,  corporate
proceedings  of the Board of  Directors  relating to the  issuance of the shares
of Stock, and such other documents,  corporate  records and questions of laws as
we have deemed necessary to the rendering of the opinions expressed below.

         Based upon the  foregoing,  we are of the  opinion  that the  1,250,000
shares of Stock to be issued by the Company,  as  described  in the Plans,  will
be legally  issued,  fully paid and  non-assessable  when issued and paid for in
the manner contemplated in the Plans.

         We hereby  consent to the  filing of this  opinion as an exhibit to the
Registration Statement.


                                                              Very truly yours,



                                                              Baker & McKenzie

                    Consent of Independent Public Accountants

     As independent public  accountants,  we hereby consent to the incorporation
by  reference  in this Form S-8  Registration  Statement  of our  reports  dated
October 29, 1998,  included in  Transaction  Systems  Architects,  Inc.'s Annual
Report on Form 10-K for the fiscal  year  ended  September  30,  1998 and to all
references to our Firm included in this Registration Statement.

                                                             Arthur Andersen LLP

Omaha, Nebraska,
   February 24, 1999