8-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report: July 29, 2005

(Date of earliest event reported)

_________________________

TRANSACTION SYSTEMS ARCHITECTS, INC.

(Exact name of registrant as specified in its charter)

Delaware	0-25346	47-0772104
(State or other jurisdiction of incorporation	(Commission File Number)	(I.R.S. Employer Identification No.)

224 South 108th Avenue,

Omaha, Nebraska 68154

(Address of principal executive offices, including zip code)

(402) 334-5101

(Registrant’s telephone number, including area code)

_________________________

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

o Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

    o     Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o     Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o     Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 2.01. Completion of Acquisition or Disposition of Assets.

On June 29, 2005, Transaction Systems Architects, Inc. (the “Company”) entered into an Asset Purchase Agreement (the “Agreement”) with S2 Systems, Inc. (“Seller”). In accordance with the terms of the Agreement, on July 29, 2005, the Company purchased substantially all of the assets of Seller and its subsidiaries for a purchase price of $35 million, as adjusted based on closing working capital, plus specifically assumed liabilities. A copy of the Agreement was previously filed by the Company on a Form 8-K dated July 1, 2005.

        On July 29, 2005, the Company issued a press release announcing the completion of the acquisition of substantially all of the assets of Seller. A copy of this press release is attached hereto as Exhibit 99.1.

Item 9.01. Financial Statements and Exhibits.

Exhibit 99.1 -- Press Release dated July 29, 2005.

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

	TRANSACTION SYSTEMS ARCHITECTS, INC.
Date: July 29, 2005	By:	/s/ Dennis P. Byrnes
		Dennis P. Byrnes Senior Vice President, General Counsel and Secretary

EXHIBIT INDEX

Exhibit Number	Description
99.1	Press Release dated July 29, 2005.

EX-99.1

Exhibit 99.1

News Release

TRANSACTION SYSTEMS ARCHITECTS INC

224 SOUTH 108 AVENUE

OMAHA, NEBRASKA 68154

402.334.5101

FAX 402.390.8077

For more information contact:

William J. Hoelting

Vice President, Investor Relations

402.390.8990

FOR IMMEDIATE RELEASE

Transaction Systems Architects Completes Acquisition of S2 Systems

(OMAHA, Neb.—July 29, 2005)—Transaction Systems Architects, Inc. (Nasdaq: TSAI), a leading global provider of enterprise e-payments solutions, announced today that it has completed the acquisition of substantially all of the assets of S2 Systems.

About Transaction Systems Architects, Inc.

The Company’s software facilitates electronic payments by providing consumers and companies access to their money. Its products are used to process transactions involving credit cards, debit cards, secure electronic commerce, mobile commerce, smart cards, secure electronic document delivery and payment, checks, high-value money transfers, bulk payment clearing and settlement, and enterprise e-infrastructure. The Company’s solutions are used on more than 1,755 product systems in 79 countries on six continents. Visit Transaction Systems Architects, Inc. on the Internet at www.tsainc.com.