CONCORD, Mass., September 29, 2003 -- OneSource Information Services, Inc. (NASDAQ: ONES), a leading provider of business information solutions, today announced the OneSource® CatalystSM product family of business intelligence modules designed to maximize the productivity of customer-centric functions and organizations. The first of the application modules being introduced is the Catalyst / Account Intelligence Module for Siebel eBusiness Applications, a pre-built component for Siebel 7 and Siebel 7.5 that increases sales effectiveness and performance by delivering comprehensive business information from the Enhanced Information WarehouseTM repository directly into the Siebel Systems environment.

The new OneSource Catalyst modules integrate critical business information, including news, company profiles and financial data into applications that support key business processes, such as customer relationship management (CRM) systems, portals, and productivity tools such as spreadsheets. Catalyst modules reduce the overall amount of time users spend searching for key data about clients and prospects, and help users make effective use of that data to advance their competitive position and strengthen their customer relationships.

“Our customers gain competitive advantage when they obtain the information we provide from directly within their established business processes and applications, and we wanted to provide the fastest, most robust route to that goal,” said Dan Schimmel, CEO of OneSource. “Catalyst modules will address this need and augment our two existing product lines by offering easy-to-deploy modules directed at specific applications and tasks.”

The OneSource Catalyst / Account Intelligence Module for Siebel eBusiness Applications is designed to enable sales organizations to improve effectiveness through shortened sales cycles and more rapid market penetration. Users of the Account Intelligence Module for Siebel can benefit from increased sales team productivity through a reduction in time and effort spent preparing for sales calls, while also gaining competitive advantage through more effective and strategic account planning. In doing so, organizations can realize a greater return on their CRM investment.

"At Fleet, our Business Advisor platform, built with Siebel technology and in use by all corporate relationship managers and product specialists, is central to our client acquisition and retention initiatives. We have worked successfully with OneSource to leverage OneSource''s comprehensive business information from this platform," said Jim Eardley, managing director of sales and marketing systems, Business Development & Strategy at FleetBoston Financial. “The Catalyst / Account Intelligence Module for Siebel promises to make usage of OneSource within key business processes even easier, and focus customer-facing roles on serving customer needs, not searching for data.”

Key features of the Account Intelligent Module for Siebel include:

• Complete Account Profiles: Delivered directly within Siebel 7 and Siebel 7.5, Account profiles include rich business description, analyst reports, news and articles, senior and mid-level executive contacts, corporate family structure information and full financial statements and public filings.
• Personalized News Alerts: Based on individual account lists and selected business topics, OneSource delivers the latest news for the user’s accounts directly within any Siebel screen, eliminating the need to search multiple information resources.
• Presentation Tailoring: Allowing for basic tailoring of content presentation, OneSource’s content customization capability ensures that the most important information is readily available, and that the user experience is intuitive and consistent.
• Usage Tracking: Using built-in tracking features, systems administrators and sales management can gain a full understanding of information usage of OneSource products in support of best practices, training and internal billing processes.

"We see organizations that have invested substantially in CRM systems, portals, and other systems now seek to optimize those investments and extend their competitive advantage. By enhancing the quality and depth of the information flow to their sales teams, they are more knowledgeable and prepared than their competitors." said Joe Galvin, vice president and research director at Gartner. "With the core CRM infrastructure in place, these organizations are beginning to address the ‘what''s in it for me’ demands from sales people through advanced information and intelligence capabilities."

Pricing and Availability
The OneSource Catalyst / Account Intelligence Module for Siebel eBusiness Applications is available immediately from OneSource, and is currently pending validation for integration with Siebel 7.5. Pricing is based on a per-seat annual subscription basis, with volume discounts.

Next Steps for Catalyst Modules
As OneSource continues to set the standard for value-added business information, the company will introduce additional OneSource Catalyst application modules. Each module will enable direct access to business information from the Enhanced Information Warehouse repository, the industry’s most extensive and up-to-date collection of information on 1.7 million public and private companies and 6 million executives worldwide, and will be designed to deploy quickly within a specific application.

About OneSource Information Services, Inc.
OneSource, a recognized leader in business information solutions, delivers unparalleled company, executive, and industry intelligence that make business professionals more effective and productive in completing their critical daily tasks. OneSource products and services support a company''s vital business processes including serving their customers, finding and leveraging new opportunities, and managing suppliers and partners.

OneSource combines and organizes content from over 2,500 information sources supplied by more than 30 world-class content providers, creating an unequalled information resource encompassing corporate families, industries, executives, financials, news, analyst reports, and trade and business press articles. Using its Global Business TaxonomyTM system, OneSource links this in-depth information on over 1.7 million companies worldwide resulting in the most extensive company-linked repository of business information in the world.

Users of OneSource products work faster, smarter, and more productively, whether leveraging OneSource business information through the Web-based OneSource Business BrowserSM product line or through enterprise applications or portals integrated seamlessly via the OneSource AppLink SDK. To help customers link the OneSource Enhanced Information Warehouse repository into their preferred enterprise applications, OneSource provides consulting and integration services.

OneSource is headquartered in Concord, MA, with offices located in North America, Europe, and the Pacific Rim. Product information is available at www.onesource.com. Customers include Bank One, Chubb, Citigroup, Cisco, Hewlett Packard, Deloitte & Touche, i2 Technologies, Orange, Royal & SunAlliance, SAS Institute, and Sun Microsystems.

OneSource, Business Browser, Global Business Taxonomy, Catalyst, AppLink, Enhanced Information Warehouse and/or other OneSource product and service names referenced herein are either trademarks or service marks or registered trademarks or service marks of OneSource Information Services, Inc. or its subsidiaries in the United States and/or other countries. All other product and service names mentioned herein are trademarks or service marks of their respective owners.

Safe Harbor Statement
This news release contains certain forward-looking statements that are based on the current beliefs and expectations of OneSource’s management, as well as assumptions made by, and information currently available to, OneSource’s management. Such statements include, but are not limited to, those regarding the functionality and effectiveness of OneSource products and services, including, but not limited to, the Catalyst modules; and OneSource’s competitive position. Because such statements involve risks and uncertainties, actual actions and strategies and the timing and expected results thereof may differ materially from those expressed or implied by such forward-looking statements, and OneSource’s future results, performance, or achievements could differ materially from those expressed in, or implied by, any such forward-looking statements. Such risks include, but are not limited to, complementing the OneSource product line with new products and services, which may divert management and technical attention and financial resources; OneSource’s reliance on generating revenues from its Web-based product line; political, economic, and business fluctuations in domestic and international markets; and competition in the business information products and services industry. In addition to the factors noted above, other risks, uncertainties, assumptions, and factors that could affect OneSource’s financial results are described in OneSource’s recent filings with the United States Securities and Exchange Commission including its Annual Report on Form 10-K for the fiscal year ended December 31, 2002.