The investment, which is subject to customary closing adjustments, marks one of the largest fundraising rounds completed for a private security company and is expected to accelerate Tenable's long-term global growth. Today's funding marks $300 million in capital raised to-date, following Accel's $50 million Series A investment in September 2012.

'Tenable has the only true continuous network monitoring offering on the market and our products defend some of the world's largest and most complex networks, keeping our customers secure in the harshest of threat environments,' said Ron Gula, CEO of Tenable. 'We are proud to partner with Insight and Accel who, with their investment and deep expertise in technology and security, will enable us to further accelerate our global growth and innovation.'

Tenable's flagship products include SecurityCenter Continuous View (SecurityCenter CV), which provides the most comprehensive and integrated view of network health, and Nessus, the global standard in detecting and assessing network data. Its superior security software uses sophisticated analytics to allow organizations a real-time view of their entire network -- on-premises, virtual, cloud and mobile and other connected devices. Customers rely on Tenable for its unmatched ability to reduce risk from increasingly severe and frequent cyber threats and to eliminate gaps in their cyber defenses.

Tenable has more than one million users and almost 20,000 customers worldwide who rely on its solutions to continuously monitor enterprise networks for vulnerabilities and threats, from some of the most recognizable brands in the world such as Deloitte, Visa, BMW, Adidas and Microsoft to public sector organizations including all arms of the entire U.S. Department of Defense. Tenable has experienced rapid growth and expansion over the years due to the global demand for its products. The company grew billings over 50% last year and has a run rate that exceeds $100 million.

'Security and vulnerability continues to be one of the largest concerns for companies across all sectors,' said Richard Wells, managing director of Insight Venture Partners. 'Tenable fits clearly within our strategy of investing in growing companies that are providing large global industry solutions. We are pleased to partner with Tenable's team to further advance the company's strategic goals.'

To position the company for continued growth, Tenable has added over 200 new employees this year and significantly expanded its channel network worldwide. With entities in 10 countries serving customers around the world, Tenable will continue to invest in international expansion with immediate plans to expand its efforts into 10 more countries including: China, Mexico, Ireland, Sweden, United Arab Emirates and India.

'Tenable's strong adoption across a diverse set of great customers reflects its position as a critical enterprise security platform,' noted Ping Li, partner at Accel. 'Discerning CISOs worldwide increasingly view Tenable products as the central hub for managing and improving their security posture amidst an ever-worsening threat landscape.'

Over the past year, Frost and Sullivan named Tenable's SecurityCenter CV as the best Continuous Network Monitoring Solution and SC Magazine Europe named Tenable the Best Security Company in 2015. Network World Asia twice awarded the company top honors for vulnerability management and continuous monitoring. Tenable was named one of the fastest growing technology companies for the sixth consecutive year by the Deloitte Fast 500 program. Tenable has also earned 'best place to work' recognition from The Washington Post, Washingtonian magazine, and The Baltimore Sun.

About Tenable Network Security

Tenable Network Security provides continuous network monitoring to identify vulnerabilities, reduce risk, ensure compliance and respond to threats. Our family of products includes SecurityCenter Continuous View, which provides the most comprehensive and integrated view of network health, and Nessus, the global standard in detecting and assessing network data. Tenable is relied upon by many of the world's largest corporations, not-for-profit organizations and public sector agencies, including the entire U.S. Department of Defense. For more information, please visit tenable.com.

Insight Venture Partners

Insight Venture Partners is a leading global venture capital and private equity firm investing in high-growth technology and software companies that are driving transformative change in their industries. Founded in 1995, Insight has raised more than $13 billion and invested in more than 250 companies worldwide. Our mission is to find, fund and work successfully with visionary executives providing them with practical, hands-on growth expertise to foster long-term success. For more information on Insight and all of its investments, visit http://www.insightpartners.com or follow us on twitter: @insightpartners.

Accel

Accel is a leading early and growth-stage venture capital firm, powering a global community of entrepreneurs. Accel backs entrepreneurs who have what it takes to build a world-class, category-defining business. Founded in 1983, Accel brings more than three decades of experience building and supporting hundreds of companies. Accel's vision for entrepreneurship and business enables it to identify and invest in the companies that will be responsible for the growth of next-generation industries. Accel has backed a number of iconic global platforms, which are powering new experiences for mobile consumers and the modern enterprise, including Atlassian, BlaBlaCar, Braintree, Cloudera, Crowdstrike, Dropbox, Etsy, Facebook, Flipkart, GoFundMe, Kayak, Lookout, Qualtrics, Spotify, Slack, Supercell, Venmo, and others.


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