CHICAGO, IL - October 1, 2001—Cognos^® (Nasdaq: COGN; TSE:CSN), the leading provider of business intelligence solutions, today announced its support for Siebel 7, the seventh major release of Siebel eBusiness Applications from Siebel Systems, Inc., (Nasdaq: SEBL), the world's leading provider of eBusiness applications software. Cognos will submit the integration of its Business Intelligence solution for validation with Siebel 7 within 90 days of general availability. The integration will provide organizations with complete eBusiness solutions that improve business relationships, increase top-line growth, and deliver measurable ROI from their customer-focused eBusiness strategy.

Siebel Systems enables software vendors to easily integrate solutions through its open, extensible, advanced Smart Web Architecture. Unlike rudimentary HTML clients, Siebel Smart Web Architecture combines a zero-footprint, browser-based Web client and a user interface with levels of interactivity and usability traditionally available only in Windows applications. The Siebel Smart Web Architecture enables organizations to leverage the industry's best eBusiness applications at the lowest total cost of ownership.

Siebel 7 extends the reach and functionality of Siebel Systems' industry-leading suite of integrated, multichannel eBusiness applications, enabling organizations to translate customer relationship strategy into execution by effectively aligning and rapidly integrating channels, employees and partners. Siebel 7 allows organizations to manage, synchronize and coordinate all customer touch points across the Web, call center, field sales and service personnel, and partner channels.

Cognos is a Premier Software Partner of Siebel Systems, Inc., and its products have been validated with Siebel eBusiness Applications, version 6. The integration of the Cognos Business Intelligence solution with Siebel 7 will further enhance customer benefits, providing cutting-edge technology to harness corporate data and make faster, more informed business decisions. The joint solution unites information from across organizations to give a consistent, unified view of business processes, ensuring that the appropriate information gets to the right people, at the right time, and in the most usable format.

"The basis for successful loyalty relationships is providing a full-service approach. Siebel Systems enjoys a leading position in the customer-facing eBusiness market and Cognos is pleased to be supporting Siebel 7," said Patrick O'Leary, Cognos Vice President of Strategic Alliances. "Siebel 7 further establishes Siebel Systems as a leader in eBusiness applications software, especially where organizations require an enterprise solution that enables them to reduce costs to acquire, service, and support customers."

"The integration of Siebel 7 with Cognos combines value added analytics and a highly interactive web client for our customers," said Catherine Cherubino, Senior Managing Director, Software and Industry Alliances for Siebel Systems. "Our joint solution will leverage the eBusiness strategies of companies, helping them to build stronger, more profitable relationships with customers, partners, and suppliers."

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 eBusiness applications software, enabling multichannel sales, marketing, and customer service systems to be deployed over the Web, call centers, field, reseller channels, retail, and dealer networks. Siebel Systems' sales and service facilities are located in more than 37 countries. For more information, please visit Siebel Systems' Web site at www.siebel.com.

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 and partner relations, such as the availability of Siebel Systems' products and services, customer implementation of products and services, relationships with third-party vendors and systems integrators, 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 for the year ended December 31, 2000 and its other filings with the Securities and Exchange Commission.