Joe Sluys

Founder and ceo

Prior to setting up SquareBook in 2017 Joe was CEO of Sentronex, a financial markets technology and consultancy business that he founded in 2005. Under Joe’s leadership Sentronex grew to work with over 50 regulated institutions including Goldman Sachs, JP Morgan and BlackRock. The Sentronex client list included a substantial number of UK IPO Sponsors and Nomads. As CEO Joe made two strategic company acquisitions before selling the business in 2016 to pursue SquareBook.

Over the last decade, Joe has served as director of SNX Systems and non-executive director of netConsult Ltd. Joe also works as a mentor and occasional lecturer in entrepreneurship at Edinburgh University.An economics graduate from Sussex University, Joe has been involved with the IPO market since joining the investment bank WestLB in 1999.

Richard Balarkas

Co-Founder and Non-Executive Chairman

Richard is an industry veteran with over 30 years experience leading innovation in electronic trading, stock exchanges and market structure. He has a proven track record in building and running successful global businesses with $1bn revenue streams. He advises and sits on the boards of several firms including CBOE Ltd (Europe’s largest stock exchange), Saxo Capital Markets, Compliance Solutions Strategies, Goldex and FIX Protocol. Richard served as CEO and President of Instinet Europe; Global Head of electronic trading at Credit Suisse, Global COO for equity trading at BZW; and Head of National Market Development at the London Stock Exchange. Richard is the founding CEO of CISCO (City Group for Smaller companies), now renamed QCA (Quoted Company Alliance) where he successfully spearheaded the campaign to establish stock exchanges for European SME’s.

Mark Parnell-Hopkinson

Co-Founder and Chief Technical Officer

Since 1995 when he first started working in financial services, Mark has held a number of key positions at City brokers, IT providers and stock exchanges. These include Head of Operations, Managing Director and CTO. Mark was founding CTO at Plus Markets where he was part of the team that gained authorisation. Mark and Joe worked together at Sentronex.

Fred Huibers


Fred brings more than 30 years’ experience in corporate finance and investment to SquareBook. Previously, he was Head of Asset Management at Rabobank before he moved to ING, where he was responsible for international Equity Capital Market activities. Most recently, Fred entered academia as a Professor of Corporate Finance and Fintech at the Amsterdam University of Applied Sciences. He is one of the world’s leading authorities on primary market issuance and continues to carry out ground-breaking research in this field.

Barry Wingate


Barry has over 20 years experience working in investment banking and financial markets. He led the coverage of the energy services sector within HSBC’s Global Banking division before working with Buckthorn Partners on private equity transactions. Barry’s experience in high profile M&A and capital markets transactions gives him a wealth of connections amongst financial intermediaries, sponsors and corporates.

Square Book Finance Ltd (Company Reg No. 11971730) is authorised and regulated by the Financial Conduct Authority (number 812594)