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Who we are
At Big Pi we bring a well-rounded perspective to tech investing - having experienced the journey from every angle. Big Pi team members have helped build tech companies from zero to global; developed groundbreaking technology with unique IP and global impact; invested across diverse industries & tech subsectors, sizes and stages; advised businesses & shareholders, from securing early and growth stage fundraising across the capital structure to executing rollup strategies, large scale M&A and multi-billion-dollar IPOs.
Our team has worked through booms and crises, with small and large enterprises across the globe. We have also demonstrated time and again that Greece and the Southeast European region (including their diaspora) can provide fertile terrain for technology companies serving international markets, thanks primarily to exceptional talent and cost-effective operating hubs - themes that we are systematically further building on. We invest both our capital and expertise, helping entrepreneurs & businesses navigate their paths to success.
Cassandra joined Big Pi in June 2023. She engages in all stages of the investment process, from sourcing, to due diligence and deal closing, to portfolio monitoring. In addition, she oversees the Fund’s finance and investor reporting requirements.
Prior to joining Big Pi, Cassandra spent nine years conducting translational biomedical research in academia and the pharmaceutical industry at the University of Cambridge, Harvard Medical School, and Almirall S.A. She has authored nine peer-reviewed articles in top-tier scientific journals, including Nature Medicine. In parallel with her Ph.D. studies, she applied her life science expertise towards evaluating startups and identifying risks as a part-time Analyst at Start Codon VC.
Cassandra holds a Ph.D. in Oncology from the University of Cambridge, an M.Res. in Biomedical Research from Imperial College London, and a B.Sc. in Biomedical Science with an Extramural Year in Industry from King’s College London.
Nikos has been a Partner at Prime Ventures, a pan-European Venture Capital and Growth Equity Fund based in Amsterdam, with around $1 billion in Assets under Management, which he joined in 2015. Nikos has led investments in several European technology companies, ranging from €5-€30 million per company. He has invested and/or served on the Boards of Blueground, Holidu, aiMotive (acquired by Stellantis), Zappi, Bright Computing (acquired by NVIDIA).
Before Prime Ventures, Nikos worked in the venture capital sector with the corporate VC fund of Randstad (Randstad Innovation Fund) and with Dutch Expansion Capital.
He holds an integrated Masters in Computer Engineering and Informatics from the Engineering School of the University of Patras and a MSc in Finance and Investments (with distinction) from Rotterdam School of Management.
Melina joined the team in January 2023. Her responsibilities involve deal sourcing, evaluation, due diligence, deal structuring, and portfolio support.
Before joining Big Pi, Melina worked as a management consultant at McKinsey & Company, where she contributed to strategy and operations projects for pioneer companies in various sectors, such as Energy, Banking, Insurance, and Telecommunications.
She holds an Integrated Master's in Electrical and Computer Engineering from the National Technical University of Athens, with her diploma thesis focusing on deep learning.
Marco co-founded Upstream with Alex Vratskides in 2002, and was its CEO until 2017. During his tenure, Upstream reached revenues of €230m and a team of +400 employees, until Actis acquired a majority in 2014. Marco is also a shareholder and co-founder of Persado, which started as an R&D unit within Upstream, and was spun out as a stand alone company in 2012, with Bain Capital Ventures as lead investors. 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, SoftOne, and Softomotive (acquired by Microsoft). Marco is a board member at the Hellenic Federation of Enterprises (SEV), Endeavor, the Foundation for Economic and Industrial Research (IOBE), Junior Achievement and diaNEOsis think tank. Marco received the EY Greek “Entrepreneur of the Year” award, in 2013, and holds an MA from Warwick University and an MPhil from Oxford University.
Maria is the Office Manager, responsible for business operations and team support.
She joined the team in June 2023, since then she coordinates and organises office administrative procedures, and liaises with external parties.Prior to joining Big Pi, Maria was the Office Manager of Upstream for two years, where she managed the administrative and day-to-day requirements of over 300 employees.
Maria holds a BSc. in Political Science and Public Administration from the National and Kapodistrian University of Athens and an MA. in International Relations and Strategic Studies from Panteion University.
Alex is an engineering academic and entrepreneur. In 2005 he co-founded Vidyo, a videoconferencing systems company that was acquired by Enghouse in 2019. 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 is also co-founder and Executive Chairman of Coretas, a company using AI on social media to optimize targeting in digital marketing. Prior to transitioning to professional investing, he has been an active angel investor with exits to Facebook and Dell.
He has been involved in video compression and communication research and standardization for nearly 30 years, with more than 150 patents internationally. His inventions are used in global video coding standards such as H.264/AVC and H.265/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 is also a certified offshore skipper and sailing instructor of the American Sailing Association and an avid musician (bouzouki).
Guy has significant product and scaling experience with technology companies. He was a co-founder of Persado ($100m ARR AI company), Bryq and early employee and later CEO of Upstream.
He is a holder of multiple patents for innovative AI solutions in marketing and HR Tech. He has also been an active angel investor and Board Member in many startups including Spotawheel, Carge (exit to PPC), Pandas and Convert Group.
Guy holds a M.A. in Social Psychology from Sorbonne University.
Fanis brings 15 years of investment banking and in-house corporate finance/CFO experience.
Prior to joining Big Pi Ventures, he worked at FlexCar, the vehicle-as-a-service scale-up. Initially, he held the position of Corporate Finance Director, overseeing the multi-hundred million financing activities (equity & debt) for the group, before assuming the role of Group CFO, responsible for all finance-related functions across FlexCar’s four geographical markets.
Fanis commenced his career at Société Générale’s TMT corporate finance team in London, where he stayed for three years. He then spent seven years at Akira Partners, the London-based boutique investment bank specializing in the TMT sector. Throughout his investment banking career he has executed a wide spectrum of M&A, growth capital, JV and public-to-private transactions, advising clients ranging from scale-up/growth capital companies to large corporates and private equity funds.
Fanis holds a BSc in Economics and Finance from the University of Bristol (first class) and a Master’s degree in Finance from Imperial College Business School.
Vassilis is a Business Development & Strategy leader with a strong track record of commercial partnerships and global sales campaigns in the technology industry.
He is currently the Head of Ecosystem for Matter Labs, the inventor of ZKsync, an Ethereum L2 protocol designed to scale blockchains like the Internet. Prior to Matter Labs, Vassilis held various leadership positions at Microsoft.
Vassilis is also an angel investor in Crypto and AI startups like Modulus Labs, Giza AI and Hyperbolic. He is based in Seattle, USA.
George is an Operating Partner at Big Pi Ventures, where he oversees some of our portfolio companies. Additionally, he founded Greek Grape Company in 2017, which specializes in growing late seedless table grapes sustainably for major European supermarkets.
From 2013-2017, George served as President of SouthWestern Europe for IPG MediaBrands, where he was 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 served as Executive Director of Ogilvy & Mather, Greece's leading and most profitable communications group, and as Google's country manager, where he established the local office. After leaving Google, George founded 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 and a BSc in Management Sciences from Warwick University. He has also attended multiple executive courses in various topics, including Private Equity (Oxford), Finance (Alba), and Negotiations (Harvard), and has completed multiple online courses (ranging from Shipping and AI to Introduction to Molecular Biology). He is fluent in Greek, English, and French and has a working knowledge of Italian.
In his youth, George was an avid athlete who participated in multiple sports, earning six national medals and being part of the National Greek team in Shotokan Karate for four years. He currently serves as vice president of the Greek Karate Federation.
Aristos is a pioneer of private equity and venture capital in Greece. He was a founding partner of Big Pi’s first fund and he is still advising some of its portfolio companies. He holds the title of Emerirus Partner as he is not involved with Big Pi’s later funds. He has been recognized in 2023 by the Hellenic Development Bank of Investments with a lifetime achievement award for the development of the Greek VC ecosystem.
Over his long career as investment manager, he has invested in technology startups (with Openfund), as well as 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 served on the boards of over 20 companies and taken on an active executive role in some.
In addition, Aristos is a well-known analyst of the Greek economy and society. He has extensive experience in management consulting and public policy advice. He is on the board of think tanks like IOBE and diaNEOsis, and Vice-Chair of ESETEK, which advises the government on research and technology policy.
Aristos holds a BA in Social Studies from Harvard and an MSc in Economics from Birkbeck College, London.