S2 Systems, Inc. was acquired by Transaction Systems Architects Inc. on July 29, 2005. S2 Systems, Inc. provides transaction processing, authorization, and integrated solutions for the banking, financial services, retail, telecommunications, utilities, and travel and hospitality industries worldwide. The company offers OpeN/2 enterprise payment transaction platform solution, which enables applications streamline electronic funds transfer, card activity, and check management. S2 Systems also offers support, professional, and training services. Its strategic partners include IBM and Unisys. The company was founded in 1993 and is headquartered in Dallas, Texas. S2 Systems also has offices in Plano, Texas; Middlesex, the United Kingdom; Stockholm, Sweden; Riyadh, Kingdom of Saudi Arabia; Dubai, United Arab Emirates; Melbourne, Australia; and Alphen Aan Den Rijn, the Netherlands.