pellettSince 2001 Selwyn has founded and co-founded a number of technology start-ups initially focusing on network security solutions for telecommunications, financial services and government customers and telematics solutions for use in large vehicle fleets. As the co-founder, former CEO, Chair and now director of Endace Ltd he was instrumental in the company becoming the first New Zealand registered company to list on the UK's AIM stock market in June 2005. Endace has operating entities in New Zealand, Singapore, America, China and the England and in 2009 has a market capitalisation of $154 million.

In July 2007 Selwyn stood down as CEO of Endace to re-focus on acquisitions and the commercialisation of Imarda a Telematics (in-vehicle electronics) business. Imarda currently has operations in New Zealand, Singapore, Australia, USA and UK and has recently secured multi-million deals in the US and Australia. Selwyn has personally supervised the market entry of Endace and Imarda into America, Canada, UK, Ireland, Germany, Demark, Israel, UAE, Switzerland, Finland and almost every country in Asia Pac including China and Japan. He has also established multiple physical operating companies in Australia, Singapore, China, Malaysia, UK and America. Collectively Endace and Imarda now enjoy significant global commercial relationships with Tier 1 and Fortune 500 companies a few as well as significant relationships with many western intelligence gathering services.

His other current business interests include being a director of high-end audio distributor, Storm Distribution, an Australian based trucking company, North Star, and non-executive director of technology marketing and communications company, Swaytech.

Selwyn is passionate about helping New Zealand to develop a high-wage, high-growth, elaborately transformed and sustainable economy. He has consulted with government ministers and advisors on industry and economic policy, and been involved in numerous initiatives aimed at building and retaining skills and expertise to support economic growth in New Zealand. These include being a founding member of the NZ Intellectual Capital Foundation (NZInc), being a Trustee of the NZ HiGrowth Project and more recently the founder and driving force behind the NZ Productive Economy Council. He was also instrumental in establishing the first Hi-Tech Awards and has remained involved ever since.