Colin Hall - CEO

Colin Hall is the Head of Investments of GBL and the CEO of Sienna Capital.

Previously, he worked at Rhône Group, a private equity firm.

Mr. Hall holds an MBA from the Stanford University Graduate School of Business.

Johann Dumas - CFO

Johann Dumas joined Sienna Capital in October 2018 as CFO. He is based in Luxembourg.

Before joining Sienna Capital, Johann was the CFO of Quilvest Private Equity, a family-owned asset manager. Johann started his career in the audit department of KPMG Luxembourg where he specialized in IFRS and consolidation for leading industrial, commercial and private equity firms. Then, he headed the Finance department of Transcom, a global customer experience specialist.

Johann is chartered accountant in Luxembourg. He is a graduate of ICN Business School and holds a Master in Accounting and Finance from the University of Nancy. More recently, he graduated from the Advanced Management Program of INSEAD in 2017.

Ruairi Keeley

Ruairi is the Financial Analyst at Sienna Captial.

Mr. Keeley formerly worked as a Credit and Portfolio Analyst at 23 Capital and has previous experience with roles at EQT Partners, 3i Group and GFC Economics.

He holds an MA from the University of St Andrews.


Vincent Noël joined Sienna Capital’s Luxembourg office in 2015 as Financial Accountant/Controller.

Previously, he spent five years working at GDF Suez in Luxembourg.

He holds a BA in Accounting from the Haute École Robert Schuman in Libramont-Chevigny, Belgium.

Antonina Rogler

Antonina Rogler is an Accounts Assistant at Sienna Capital.

Mrs. Rogler worked in Finance and event management sectors as an administrative assistant and receptionist in Moscow and Paris.

Mrs. Rogler graduated in Management at The State University of Management in Moscow. She also holds a degree in Management from the Paris-Dauphine University in Paris.

Victoria Bond

Victoria Bond is Office Manager of the Sienna Capital London office and Executive Assistant to CEO Colin Hall.

Victoria joined Sienna Capital in December 2017 from executive search firm Egon Zehnder, prior to this she assisted the founders of Maverick Advertising & Design in London.

Victoria holds a BSc in Geography from University College London.