2/24/2018 S-1 Table of Contents Expand our ecosystem Our open and thriving ecosystem fosters deeper relationships with our users and makes Dropbox more valuable to them over time. The scale and reach of our platform is enhanced by a number of third­party applications, developers, and technology partners. As of December 31, 2017, Dropbox was receiving over 50 billion API calls per month, and more than 500,000 developers had registered and built applications on our platform. Our Market Opportunity Over the past decade, Dropbox has pioneered the worldwide adoption of file sync and share software. We’ve since expanded our capabilities and introduced new product experiences to help our users get work done. For the second consecutive year, Gartner has named Dropbox a leader in their Magic Quadrant for Content Collaboration Platforms. Our addressable market includes collaborative applications, content management, project and portfolio management, and public cloud storage. IDC estimates that investment in these categories will total more than $50 billion in 2019. As one of the few large­scale collaboration platforms that serves customers of all sizes, we also have an opportunity to reach a broad population of independent knowledge and creative workers. We believe that this market hasn’t traditionally been included in IT spending estimates. Risk Factors Summary Our business is subject to numerous risks and uncertainties, including those highlighted in the section titled “Risk Factors” immediately following this prospectus summary. These risks include, but are not limited to, the following: • Our business depends on our ability to retain and upgrade paying users, and any decline in renewals or upgrades could adversely affect our future results of operations. • Our future growth could be harmed if we fail to attract new users or convert registered users to paying users. • Our revenue growth rate has declined in recent periods and may continue to slow in the future. • We have a history of net losses, we anticipate increasing expenses in the future, and we may not be able to achieve or maintain profitability. • Our business could be damaged, and we could be subject to liability if there is any unauthorized access to our data or our users’ content, including through privacy and data security breaches. • Our business could be harmed by any significant disruption of service on our platform or loss of content. • We generate revenue from sales of subscriptions to our platform, and any decline in demand for our platform or for content collaboration solutions in general could negatively impact our business. • Our business depends upon the interoperability of our platform across devices, operating systems, and third­party applications that we do not control. • We operate in competitive markets, and we must continue to compete effectively. • We may not be able to respond to rapid technological changes, extend our platform, or develop new features. 5 https://www.sec.gov/Archives/edgar/data/1467623/000119312518055809/d451946ds1.htm 12/235