Acquisitions have long played a key role in Cisco's build, buy, partner, invest and co-develop innovation strategy. They help position us to enter new growth markets and extend our leadership in priority areas such as security. That's why I am excited about our intent to acquire Duo Security, the leading provider of unified access security and multi-factor authentication delivered through the cloud.
Duo helps protect organizations against cyber breaches by making security easy and effective based on the trustworthiness of users and devices. The company's cloud-based software solution verifies the identity of users and the health of their devices before granting them access to applications -helping prevent breaches and account takeover. Read more about how this acquisition will impact our technology strategy in a blog by David Goeckeler, executive vice president and general manager of Cisco's networking and security business.
In addition to Duo's expected impact on Cisco's strategy, I am extremely impressed by the Duo team and the business it has built. Dug Song and Jon Oberheide, Duo's co-founders, have a rich history in security and have created an organization and culture that have led to Duo being one of the most admired companies in security. Duo has distinguished itself with customers because of its ease of use and the experience end-users have with its products. In fact, about 75 percent of Duo's customers are up and running in less than a week, compared to six to 12 months for comparable products. This focus on customer success has led to over 12,000 customers, including over 100 of the Fortune 500 companies, strong renewal rates, and a very impressive net promoter score.
And customer experience is only the start in what has made Duo a great company, not only in security, but in SaaS in general. Duo has demonstrated strong top-line growth, that is substantially all subscription-based, with healthy margins, built upon a successful go-to-market engine that has allowed it to access customers from small- and medium-sized businesses to multinational enterprises.
Finally, it is worth recognizing that Cisco is both the leader in networking and also the largest enterprise security vendor in the world. This means that Duo's opportunity with Cisco extends well beyond security to Cisco's entire intent-based networking strategy. Cisco's ability to drive Duo's relevance across the entire extended enterprise, both through our integrated security and network architecture, as well as through our go-to-market channels, gives me confidence that we have the opportunity to deliver significant value with this acquisition.
Duo has about 700 employees working from offices in Ann Arbor, Mich.; Detroit, Austin, Texas; San Mateo, Calif. and London. We expect the acquisition to close in the first quarter of Cisco's fiscal year 2019.
I am very excited to welcome the Duo Security team to Cisco.