ABOUT REBECCA LEWIS
Decisions
are human.
As CEO of a public equity firm managing US$5 billion for leading institutions, I spent much of my working life making decisions. Travelling through markets with some of the world’s best investors taught me about judgement beyond the data. How we decide when the future is uncertain reveals much about who we are, and what we stand for.
Like you, my most important choices have happened far beyond work. My route has taken me from state school in the North of England to Cambridge University, from teaching mathematics to teenagers to leading an investment firm. Fifteen years living in Asia and hundreds of visits to companies and markets broadened my perspective. Coming out, marrying my wife and becoming a mum have shaped me as much as any professional experience.
Investment taught me to look closely at businesses. Leadership taught me to pay attention to people. Teaching teenagers taught me to make complex ideas accessible. Today, training in coaching and psychotherapy is deepening my curiosity about how we understand ourselves and find our way.
It’s this curiosity that I bring to On Judgement: an interest in the person behind the decision, and in what their experience might help the rest of us recognise in our own lives.
What have you learnt that has never been taught?
Rebecca Lewis · Host, On Judgement
REBECCA LEWIS · HOST, ON JUDGEMENT
Beyond the CV.
At Arisaig Partners, I served on the investment committee, travelled extensively to understand companies and markets, and worked alongside endowments, foundations, pension funds and families making decisions about long-term capital.
My route here has not been a straight line. From state school to Cambridge. From teaching to investing. Fifteen years living overseas. Coming out, becoming a partner and a mum. And, more recently, training in psychotherapy.
Different worlds, but the same question keeps returning: how do we make a decision when the outcome is unknowable and the responsibility is ours?
What have you learnt that could never be taught?
That is the question behind On Judgement: conversations with exceptional investment decision-makers about experience, uncertainty, mistakes, conviction and the things no model can tell us.
Watch the episodes
It’s time to make institutional-grade thinking accessible.
Conversations with people who have had to decide. Investors, founders and leaders share the choices that shaped their portfolios, their careers and their lives.
We explore conviction, uncertainty, trade-offs and mistakes—so you can reflect on your own approach to judgement.
HOSTED BY REBECCA LEWIS
Career
People not the screen
Nearly two decades investing taught me that the most important information isn’t on a screen. At a USD 5bn public equity firm, thousands of meetings helped me understand companies and markets, with sustainability central to that work. I worked alongside endowments, foundations, pension funds and families making decisions about long-term capital and what makes businesses endure.
I led the firm through founder succession aligning strategy, culture and people to a new generation of partners. More recently, I integrated AI into investment research and explored where human judgement remains.
Before investment, I taught mathematics and led a year group at United World College of South East Asia in Singapore. Teaching taught me to make complex thinking accessible. Sustainability research and work with the UN Global Compact broadened my perspective.
I sit on a range of fund and company boards debating allocations, strategy and stewardship, and nonprofit boards weighing funding decisions. Different organisations, with a shared responsibility to ask good questions and make thoughtful choices.
Education
Lean into learning
From state school to Cambridge University (twice), then INSEAD and Harvard Business School, I have always been drawn to learning, and to the effort it takes to understand something properly. Psychology gave me a way to think about how people see the world. Training as a teacher challenged me to explain ideas clearly. Business and leadership study then helped me connect that human understanding with the decisions organisations face.
Study & qualifications
Harvard Business School
Advanced Management Programme, 2021.MIT Sloan
Sustainability Strategy, 2012.INSEAD
Master of Business Administration, 2009.University of Cambridge
BA Hons/ MA Natural Sciences (Psychology) (1999) and PGCE Mathematics (2003)
HARVARD BUSINESS SCHOOL
Advanced Management Programme, 2021
INSEAD
MBA, 2009
MIT SLOAN
Sustainability Strategy, 2012
Passions
High performance sport
Sport has shaped how I think about effort, resilience and working with others. As a former GB heptathlete and a member of Cambridge’s winning Women’s Blue Boat in 1999, I learned to value preparation, resilience and the shared responsibility of a team. Those lessons have stayed with me long after the finish line.
Behavioural finance
I am interested in how experience, emotion and assumptions shape judgement, and how understanding ourselves can help us make better decisions. Beyond my psychology degree, I am continuing my studies through executive coaching with Meyler Campbell (2026–2027) and psychotherapy training at the Connexus Institute (2024–2027).
Diversity & inclusion
I want to help create space for people whose perspectives might otherwise go unheard. I am a mentor with Girls Are Investors (GAIN) and also recognised as an LGBTQ Gamechanger in 2023. Both connect with a belief that runs through my work and my life: we make better judgements when we listen to people who see things differently.