Leading Market Research Firm Ranks Siebel Systems the Worldwide CRM Market Share Leader.

SAN MATEO, Calif. -- Siebel Systems, Inc. (NASDAQ:SEBL), a leading provider of customer-facing solutions, has been recognized as the global market share leader on a revenue basis in the CRM applications market. According to market research firm IDC, Siebel Systems captured 10.7 percent of the worldwide CRM applications software market in 2004 compared to the closest competitor, which captured a 6.8 percent market share.(1)

IDC's report, entitled, "Worldwide CRM Applications 2004 Vendor Shares: Let the Games Begin," is based on vendor-reported and observed trends, 2004 license and maintenance revenues, and in-depth vendor surveys and analysis. The firm examined 153 providers of "packaged software," which is defined as software that is commercially available through sale, lease, and rental or as a service, and included marketing automation, sales automation, customer service, and contact center applications.

"This report confirms that CRM is a viable, growing market and that Siebel Systems remains the market-leading player," said Bruce Cleveland, Senior Vice President, Products, Siebel Systems. "We have over 11 years of experience, more than 3 million live users at more than 4,000 of the world's largest and most respected organizations, and some of the world's largest CRM deployments, each spanning tens of thousands of users. This positions us well to continue to lead the market and help our customers achieve outstanding business results by helping them build their business around their customers."

"Siebel Systems continues to lead in the CRM applications market," said Mary Wardley, Vice President, CRM Applications, IDC. "Siebel has consistently strengthened and expanded its CRM applications. In addition, by providing service offerings like its Customer Experience Blueprint to help companies understand the business issues involved in their deployments, Siebel Systems is on the right track to continue to deliver customer value in the next phase of CRM."

The report also outlined key market dynamics that are of increasing importance to organizations implementing CRM applications and that will continue to drive market growth. IDC believes that vendors providing solutions that address on demand, analytics, and business processes such as solving the lead-to-customer or order-to-cash flows will have an advantage in solving customer demands.

Siebel Systems is already capitalizing on the market dynamics outlined in the report. By leveraging its unrivaled experience and expertise in CRM, Siebel Systems is continuing to expand its comprehensive CRM solutions into broader customer-facing solutions. The company has enhanced its market-leading Siebel 7.x enterprise CRM suite to effectively address critical business process issues such as the quote-to-cash process by enabling companies to more efficiently create, validate, and manage customer quotes and orders and manage pricing across multiple enterprise systems and throughout the entire order life cycle. By embedding analytics capabilities in its CRM solutions and providing its suite of business intelligence solutions, the company is helping organizations transform data from across the enterprise into actionable insight for all users. In addition, Siebel Systems is the only vendor to offer its solutions in a variety of formats--packaged, on demand, and custom-built--to provide the industry's most flexible choice of deployment and pricing options.

About Siebel Systems

Siebel Systems is the world's leading provider of customer-facing solutions that deliver demonstrable business results and long-term competitive advantage. Siebel's multichannel offerings allow organizations to intelligently manage and coordinate all customer interactions across the Web, contact center, field sales/service force, branch/retail network, and indirect and partner distribution channels. Siebel solutions draw upon the company's best-in-class capabilities in customer relationship management (CRM), business intelligence, and customer data integration and can be deployed as licensed software or as a hosted service. Siebel solutions are tailored to the unique needs of 23 industries and incorporate industry-specific business processes, best practices, and business insight. They are the product of more than $2 billion in R&D investments and reflect over 11 years of experience with more than 4,000 organizations. Together with its extensive global network of alliance partners, Siebel provides the people, process, and technology expertise critical in driving business value from the deployment of customer-facing solutions. Over 3 million users worldwide in organizations of all sizes depend on Siebel solutions to deliver dramatic improvements in how they identify, acquire, retain, and serve customers. For more information, visit www.siebel.com.

(1) "Worldwide CRM Applications 2004 Vendor Shares: Let the Games Begin," by Mary Wardley, July 2005

For more information on Siebel Systems solutions and services, please visit our Web site: CRM - http://www.siebel.com/crm; OnDemand Solutions - http://www.crmondemand.com; Industry CRM - http://www.siebel.com/industry-crm; Call Center and Service - http://www.siebel.com/call-center; Sales Force Automation - http://www.siebel.com/sales-force-automation; Marketing Automation - http://www.siebel.com/marketing-automation; Business Intelligence - http://www.siebel.com/business-intelligence; Integration Solutions - http://www.siebel.com/integration-solutions; CRM Services - http://www.siebel.com/crm-services

Except for the historical information contained herein, this press release contains forward-looking statements that involve risk or uncertainties. 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 customer relations, such as the availability of Siebel Systems' products and services, customer implementation of products and services, relationships with customers, third-party vendors and systems integrators, concentration of revenues in a relatively small number of customers, existence of errors or defects in products, ability to successfully manage growth, 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' Annual Report on Form 10-K, Quarterly Reports on Form 10-Q and its other filings with the Securities and Exchange Commission, which are available at www.sec.gov. Siebel Systems assumes no obligation to update the information in this press release.

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.