Business Services Industry

Siebel Systems and AT&T Wireless Announce Strategic Alliance

Business Wire, April 30, 2001

Business Editors/High-Tech Writers

SAN MATEO, Calif. & REDMOND, Wash.--(BUSINESS WIRE)--April 30,

2001

Industry Leaders Team to Empower Mobile Professionals by Offering

Siebel eBusiness Applications via AT&T GSM/GPRS

Siebel Systems, Inc. (Nasdaq:SEBL), the world's leading provider of eBusiness applications software, and AT&T Wireless (NYSE:AWE), a leading global provider of wireless products and services, today announced a Strategic Platform Alliance to jointly market and provide wireless access to Siebel eBusiness Applications via AT&T GSM/GPRS. Combined mobile solutions from AT&T Wireless and Siebel Systems will help companies enhance the responsiveness and productivity of their field sales and service personnel while improving customer care and self-service. The scope of the alliance includes joint marketing, collaborative selling, and testing of mobile eBusiness solutions.

Through this strategic alliance, customers of Siebel Systems and AT&T Wireless will benefit from having wireless access to Siebel eBusiness Applications -- including Siebel Wireless, Siebel Handheld, and Siebel Remote applications. Target application areas and markets include field service, sales automation, financial services, energy, and communications.

Siebel Mobile Solutions provide users access to critical ebusiness information while on the go. These solutions support a wide variety of mobile devices, including WAP phones, handhelds, and laptop computers, while providing multichannel, multiplatform support for all Siebel eBusiness Applications.

"AT&T Wireless is well-known and respected in the wireless industry for delivering superior products and services to customers," said David Schmaier, Executive Vice President, Siebel Systems. "This alliance brings together two industry leaders who will consistently and reliably deliver wireless access to critical customer, employee and partner channels."

"Siebel Systems shares our vision to empower companies to do business on the go," said Don Boerema, Senior Vice President, Strategy and Business Development, AT&T Wireless. "We view this alliance as extremely important to our business and expect it to bring increased value to our joint customers."

About Siebel Systems

Siebel Systems, Inc. (Nasdaq:SEBL) is the world's leading provider of eBusiness applications software. Siebel Systems provides an integrated family of Web-based sales, marketing and customer service applications that help organizations build and manage relationships with their customers around the world. Siebel eBusiness Applications are designed to meet the needs of small, medium and large businesses. Siebel Systems' sales and service facilities are deployed locally in more than 37 countries. For more information, please visit Siebel Systems' Web site at www.Siebel.com.

About AT&T Wireless

AT&T Wireless (NYSE:AWE) operates one of the largest digital wireless networks in North America. With more than 15 million subscribers, including partnerships and affiliates, and revenues exceeding $10 billion, AT&T Wireless is committed to being among the first to deliver the next generation of wireless products and services. Today, we offer customers high-quality wireless communications services, whether mobile or fixed, voice or data, to businesses or consumers, in the U.S. and internationally. For more information, please visit: www.att.com/wireless.> Except for the historical information contained herein, this press release contains forward-looking statements that involve risk or uncertainties. The success of the acquisition and future operating results of Siebel Systems may differ from the results discussed or forecasted in the forward-looking statements due to factors that include, but are not limited to, risks associated with acquisition, such as the potential difficulties in the assimilation of operations, strategies, technologies, methodologies and products of the acquired company, the risk of loss of key personnel of the acquired company, diversion of management attention from other business concerns, business risks including the risk of variations in quarterly operating results, significant current and expected additional competition and the need to continue to expand product distribution and services offerings. Further information on potential factors that could affect the financial results of Siebel Systems are included in Siebel Systems' Report on Form 10-K for the year ended December 31, 1998 and its other filings with the Securities and Exchange Commission.

Note to Editors: Siebel is a trademark of Siebel Systems, Inc. and may be registered in certain jurisdictions. All other product and company names mentioned are the property of their respective owners and are mentioned for identification purposes only.