Dimitris Maniatis

Chief Executive Officer

Dimitris is Upstream’s Chief Executive Officer responsible for further expanding Upstream’s growth by leading its new innovative products to market. He joined Upstream in 2017 to head Secure-D. Under his leadership Secure-D has grown into an award-winning, carrier-grade security platform, trusted by 30 mobile network operators in emerging markets. Before joining Upstream, Dimitris was in advertising through ‘all things web’, the digital marketing agency he founded in 2009. In 2014 ‘all things web’ became part of IPG and was relaunched as Reprise Digital Greece, member of the global digital marketing agency network of IPG. Dimitris holds a degree in Software Engineering, from the University of Manchester, in the UK.

Kostas Kastanis

Deputy Chief Executive Officer

Kostas is Deputy Chief Executive Officer, leading the strategic development and deployment of Upstream’s product stack with a view to expanding their footprint. He joined Upstream in 2015, initially as Head of Strategy and later as Head of Zero-D, the company’s pioneering ad-funded free mobile internet platform, leading it to an addressable market of 250 million people. Prior to joining Upstream, Kostas spent 8 years with McKinsey & Company, consulting banking, telco and tech companies in Europe, Africa and Asia. He spent another 3 years with MasterCard, driving business development for Mobile Wallets in SE Europe. Kostas is a graduate of the Athens University of Economics & Business in Operations Research, holds a Master’s of Science degree in Decision Sciences from the same university as well as an MBA from INSEAD.

George Kalyvas

Chief Operating Officer

George joined Upstream in 2009 and now leads the company’s largest in population department, as Chief Operating Officer. He has built a versatile profile over the years, serving from project and account management roles to being Head of Product of the company for 3 years. George is now overseeing the company’s commercial and technical operations, globally.
He is an Engineer by education, a holder of Bachelor’s and Master’s degree in Computer Engineering from the National Technical University in Athens, and an MBA holder from Cass Business School, City University, London.

Raul Martinez

Chief Commercial Officer

Raul is Chief Commercial Officer driving Upstream’s revenue growth acceleration across existing and new markets. He joined Upstream in January 2020. Prior to joining Upstream, Raul spent more than 8 years with the Millicom Group, leading marketing, commercial and strategy functions in Latin America and Africa in Millicom’s Mobile and Mobile Money Divisions. Prior to this, Raul was leading Revenue Management and Pricing in one of Latin America’s leading Airlines after completing various commercial and strategy roles. Raul holds a Business & Economics degree from ESEN in El Salvador and a Sloan Master’s from London Business School.

Natalia Mila

Chief Technology Officer

Natalia joined Upstream in 2008 as a senior software engineer. She has worked in several roles within the company, as a team leader and later on as chief architect and head of engineering, leading the design and implementation of Upstream’s mobile commerce platform. She is now the company CTO, responsible for its technical product, engineering and infrastructure functions.
She has more than 17 years of work experience in enterprise software, in companies such as Intracom and Intralot S.A. She holds a Bachelor’s degree in Computer Science from the National and Kapodistrian University of Athens, and a Master’s degree in Distributed and Multimedia Information Systems, from Heriot-Watt University, Edinburgh.

Chrysa Karamanidi

Chief Innovation Officer

Chrysa Karamanidi joined Upstream in 2009 and soon progressed to leadership roles heading the company’s Performance Marketing, Digital Marketing and Latin America Operations divisions. In 2018 Chrysa was tasked with the development, growth and introduction to market of Upstream’s omnichannel vision, One-D, a marketing platform for accelerating digital services adoption, post-paid base growth, ARPU increase and churn reduction for mobile operators. As of beginning of 2020 Chrysa is Upstream’s Chief Innovation Officer aligning R&D and product portfolio development and roadmap with business strategy and growth targets. She holds a bachelor’s degree in Management Science and Technology from the Athens University of Economics and Business, as well as a Master of Science in Marketing from the University of Bath.

Panos Martinis

Chief Financial Officer

Panos is Chief Financial Officer at Upstream. Panos oversees the company’s finance and legal department and is responsible for financial planning and the coordination of investor relations for the business. Before joining Upstream, Panos was Business Planning and Intelligence Manager at Dell where he played a key role in the company’s penetration in the corporate market. Panos also worked in Washington D.C. as a Consultant at LECG Inc. and as an Associate at Deloitte & Touche L.L.P.
He holds a Bachelor’s degree in Finance and Public Policy Management from The Wharton School, University of Pennsylvania and a Master’s degree in Finance and Economics, from The London School of Economics.