Aristos is an economist and sociologist, who enjoys evaluating and formulating new business models.
He is a pioneer of private equity in Greece. In his 23 years as investment manager, he has invested in technology startups (with Openfund), and in growth companies across a wide range of industries, from table grapes and health clubs to book logistics and banking software (with Commercial Capital and Eikon Capital). He has participated in the boards of about fifteen companies and taken an active executive role in some of those.
Aristos is also a well-known analyst of the Greek economy and society, and has extensive experience in management consulting and in public policy advice. He holds a BA in Social Studies (Harvard), and an MSc in Economics (Birkbeck College, London).
He is the co-founder and Chief Scientist of Vidyo, an award-winning, venture-backed US-based company developing video communication software products and services (vidyo.com & vidyo.io). Vidyo has been awarded more than 190 patents worldwide, and connects millions of users around the world through its secure, scalable, cloud-based technology. Prior to Vidyo he was an Associate Professor of Electrical Engineering at Columbia University. He has also held an appointment as an Associate Professor at the University of Athens, in the Department of Informatics and Telecommunications.
He also Co-Chairs the Real-Time Communications Subgroup of the Alliance for Open Media, which just completed the design of a next-generation video codec for the Internet called AV1.
Alex has more than 100 publications, holds more than 140 patents internationally, and his inventions are used in several video coding and digital television standards, including AVC and HEVC. His awards include a WebRTC Pioneer Award (2014), a Marie Curie Chair from the European Commission (2007), and the ACM Multimedia Open Source Software Award (2004. He received his Ph.D. in Electrical Engineering from Columbia University in 1995 and his Diploma in Electrical Engineering from the National Technical University of Athens, Greece, in 1990.
He has been an active angel investor in Greece and the US.
Marco is an accomplished technology entrepreneur and active angel investor.
He co-founded Upstream with Alex Vratskides in 2002 and was its CEO until 2017. Upstream has built a mobile commerce platform operating in 42 emerging markets providing payment capabilities to 1.3b unbanked people and localized advertising reaching over 2b consumers. During his tenure the company reached revenues of Eur 230m and a team of over 350 people. In 2014 british private equity fund Actis acquired a majority stake in the business and Marco remains a shareholder and holds the role of board chairman.
Marco is also a shareholder of Persado which started as an R&D unit within Upstream and was spun out as a stand alone company in 2012. Persado, under the leadership of Alex Vratskides has become a leader and innovator in AI generated marketing language globally.
He is an early investor in numerous technology companies including Workable, Hellas Direct and Softomotive (acquired by Microsoft).
Before Upstream he was a Marketing strategist at McCann-Erickson (IPG), Grey (WPP) and DDB (Omnicom) in their London offices.
Marco is President of Junior Achievement Greece and board member at Endeavor, the Hellenic Federation of Enterprises (SEV), the Foundation for Economic and Industrial Research (IOBE), and diaNEOsis think tank. He received the EY Greek “Entrepreneur of the Year” award, in 2013.
He holds an MA from Warwick University and an MPhil from Oxford University.
George is an entrepreneur who loves ideas and scaling up teams and businesses
George is an Operating Partner at Big Pi Ventures looking after some of our Portfolio companies.
He has also founded Greek Grape Company in 2017, which specializes in growing late seedless table grapes for big European supermarkets in the most sustainable way. From 2013-2017, George was President of SouthWestern Europe for IPG MediaBrands, responsible for Interpublic’s (NYSE:IPG) media buying, planning and digital performance companies in Austria, Greece, Portugal, Switzerland and Turkey. Prior to IPG Mediabrands, George was the Executive Director of Ogilvy&Mather, Greece the best and most profitable communications group in the country and before that he was Google’s country manager where he set up the local office. After Google, George set up his own investment firm, driin, which was among the first tech angel investors in Greece.
George holds an MSc (with distinction) In Information Systems from the London School of Economics, a BSc in Management Sciences from Warwick University and has attended multiple executive courses in various topics like Private Equity (Oxford), Finance (Alba), Negotiations (Harvard) and multiple online courses (from Shipping, AI to Introduction to Molecular Biology). He also speaks Greek, English, French and can understand Italian.
When he was younger he was an avid athlete practicing many sports with highlight 6 national medals and being part for 4 years of the National Greek team in Shotokan Karate. He is now vice president of the Greek Karate Federation.
Team (full time)
Dimitris focuses on evaluating potential investment opportunities and oversees the Fund's reporting requirements
Dimitris joined Big Pi as an Investment Associate in December 2018 and was promoted to Principal in January 2021. He focuses on evaluating potential investment opportunities and oversees the Fund’s reporting requirements. His specialty and interest lie in the healthcare / pharma space.
Prior to joining big Dimitris gained 4 years of professional experience in Corporate Finance (PwC UK and Deloitte Greece) and 2 years in the pharmaceutical industry (Genesis Pharma Greece).
He holds a BEng in Chemical Engineering (UCL), MSc in Biotechnology (Imperial College), MSc in Social Sciences (LSE), and MSc in Biotech Management from Grenoble Business School.
Melina evaluates and supports technology-driven startups, utilizing her technical background to identify opportunities and risks.
She can be reached at
Melina joined the team in January 2023 as a Technology Investment Associate. Her responsibilities include evaluating and supporting technology-driven projects and startups, utilising her technical background to understand the underlying technologies and identify risks. Prior to joining Big Pi, Melina worked as a management consultant at McKinsey & Company. She holds an Integrated Master’s in Electrical and Computer Engineering from the National Technical University of Athens.
Operations Manager & Compliance Officer
She can be reached at
Maria joined Big Pi in 2018 and she is currently the Operations & Compliance Officer.
Before joining Big Pi, Maria developed a wide breadth of operational, regulatory and compliance experience working in the Finance and Shipping industries. She started her career in the Exports department at Corus Kalpinis Simos. She then moved to The Royal Bank of Scotland where the bulk of her professional experience to date was gained. Originally joining as a Credit Operations Specialist, she was promoted internally to Deputy Compliance Officer and, ultimately, Head of Business Operational Risk.
She studied law at both the London Metropolitan University (LL.B.) and the University of Southampton (LL.M.). She also holds an M.Sc. in Applied Economics from the Athens University of Economics and Business
Achilleas is Professor of Pharmacology at the Medical School of the University of Crete
Achilleas Gravanis, Co-founder of biotechnology spin-off Bionature Ltd. Professor of Pharmacology Medical School University of Crete. Researcher Institute of Molecular Biology & Biotechnology FORTH, Affiliated Research Professor Center of Drug Discovery Northeastern University Boston. He served as Member and Chairman of many research committees of the European Union, ex-chairman of Life Sciences Committee, National Council of Research & Τechnology, member of the Board of Hellenic Foundation of Research & Innovation. He has published 155 papers in PubMed (h-Index:50, Google Scholar).