Siebel and Sun Announce Global Strategic Alliance.

CHICAGO--(BUSINESS WIRE)--Feb. 24, 1999--

Siebel's Enterprise Relationship Management Applications Extend

to Support Sun Solaris and Java Technologies

Siebel Systems, Inc. (Nasdaq: SEBL) and Sun Microsystems, Inc. (Nasdaq: SUNW) today announced a global strategic alliance to bring Siebel's market-leading Enterprise Relationship Management (ERM) solutions to Sun's Solaris Operating Environment(TM) Software and Java(TM) technology-based platforms. Organizations that have built their business on UNIX can widely deploy Siebel's entirely Web-based family of sales, marketing and service applications to better build and manage their customer relationships. Through Siebel's support for thin clients based on Java technology, customers can also deploy their Siebel applications on Java technology-enabled desktops, including the Solaris Operating Environment Software, Linux and Mac OS.

"Together, Siebel Systems and Sun allow organizations to apply the full power of the Web to manage their customer relationships," said Scott McNealy, chairman and CEO, Sun Microsystems, Inc. "The Web is changing everything, and with Siebel and Sun, companies of all sizes can harness it to maximize their most important assets -- their customers."

Sun joins the Siebel Alliance Program at the highest level, as a Strategic Platform Partner. As a result, Sun and Siebel are jointly developing and marketing Siebel's family of applications to provide end-to-end support for Sun customers. The two companies are working together to bring products to market -- Siebel Server for Solaris and the Siebel Thin Client for Java.

"Siebel is committed to supporting industry standards, and many large, global organizations have standardized on UNIX," said Thomas M. Siebel, chairman and chief executive officer, Siebel Systems, Inc. "Through Sun's Solaris and Java platforms, we can offer our customers greater deployment options, while helping leverage their current technology investments."

Siebel Thin Client for Java

Siebel and Sun are working together to deliver Siebel's sales, marketing and customer service applications as Java technology-based thin clients. Using Siebel Thin Client for Java, customers can deploy Siebel applications on a variety of platforms, including the Solaris Operating Environment Software, Linux and Mac OS. This allows customers to extend the enterprise to their partners, remote sales users and customers.

Unlike application developers who are rewriting their applications in the Java programming language, Siebel can leverage its architecture -- built with reusable business components and business objects -- to quickly deliver Siebel Thin Client for Java. This ensures that current Siebel customers can seamlessly deploy their applications to the Web without writing a single line of code, lowering the total cost of ownership of their Siebel applications.

Siebel for Solaris Application Servers

The high performance and exceptional scalability of the Solaris Environment ensure that Siebel's global, enterprise customers can meet their most demanding deployment requirements. As a result, Siebel customers will now be able to take advantage of the high-performance and scalability of Sun Enterprise(TM) Servers and the Solaris Operating Environment Software.

Timing and Availability

Siebel plans to deliver the Siebel Server for Solaris and a Siebel Thin Client for Java in the second half of 1999.

About Sun

Since its inception in 1982, a singular vision, "The Network Is The Computer " has propelled Sun Microsystems, Inc., (Nasdaq: "SUNW"), to its position as a leading provider of hardware, software, and services for establishing enterprise-wide intranets and expanding the power of the Internet. With more than $10.5 billion in annual revenues, Sun can be found in more than 150 countries and on the World Wide Web at www.sun.com.

About Siebel Systems

Siebel Systems, Inc. (Nasdaq: SEBL) is the world's leading supplier of Enterprise Relationship Management software systems. Siebel Systems provides an integrated family of sales, marketing and customer service application software for field sales, customer service, telesales, telemarketing, field service, third-party resellers and Internet based e-commerce and self service. Siebel Systems products are designed to meet the needs of small, medium and large businesses. Siebel Systems sales and service facilities are deployed locally in over 20 countries and can be reached through the World Wide Web at www.siebel.com.

Note to Editors: Except for the historical information contained herein, this press release contains forward-looking statements that involve risks and uncertainties. The success of the alliance and products described above and the future operating results of Siebel Systems, Inc. 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 Enterprise Relationship Management markets, dependence on the Internet, risks associated with new versions and new products and risks associated with rapid technological change. Further information on potential factors that could affect the financial results of Siebel Systems, Inc. are included in Siebel Systems, Inc.'s Report on Form 10-Q for the fiscal quarter ended Sept. 30, 1998 and its Registration Statement on Form S-3 dated Nov. 27, 1998, which are on file with the Securities and Exchange Commission.

Siebel is a trademark of Siebel Systems, Inc. and may be registered in certain jurisdictions. Sun, Sun Microsystems, the Sun Logo, Solaris Operating Environment, Java and "The Network Is The Computer" are trademarks or registered trademarks of Sun Microsystems, Inc. in the United States and other countries. UNIX is a registered trademark in the United States and other countries, exclusively licensed through X/Open Company, Ltd. All other product and company names mentioned are the property of their respective owners and are mentioned for identification purposes only.