Greg Fisher, PhD, CFA

I am currently a Visiting Fellow at the Institute of Economics, Scuola Superiore Sant’Anna, where my work focuses on applying complexity science to asset management. My research spans non-ergodicity, the role of narratives in markets, uncertainty, model limitations, and the institutional role of asset management.

This work is part of an agenda to bridge academia and investment practice, and to develop a coherent framework — what I call Complexity Arbitrage — for understanding uncertain, evolving financial systems.

My early career was in economics and markets at the Bank of England, after earning a degree in Economics from the University of Cambridge. At the Bank, I was part of the team managing the staff pension fund, with responsibilities spanning portfolio management and strategic asset allocation. I later joined a global macro hedge fund, focusing on translating macroeconomic insights into portfolio strategy, and qualified as a CFA charterholder.

Over time, I became increasingly sceptical of standard approaches in economics and finance — particularly their reliance on mechanistic thinking. This led me to pursue a PhD in complexity science, where I studied the emergence of informal institutions such as social norms and their influence on economic behaviour. Along the way, I developed strong coding skills for data analysis and modelling. The concepts I explored in the PhD — including emergence, feedback, path dependence, and uncertainty — have clear relevance for investment practice. In 2025, I became affiliated with the Economics Institute at Sant'Anna, Pisa.

Financial systems are often approached as if they behave like stable, predictable machines. In reality, markets are complex — dynamic and interdependent, shaped by feedback, shifting narratives, episodic regimes, and continual change.

My work is grounded in the idea that understanding such systems requires more than technical skill — it requires a deep ontology, pattern recognition, adaptability, and epistemic humility. These qualities are central to how I think about investing, modelling, and decision-making under uncertainty.

This perspective underpins all my work, and I invite you to explore how it might inform your own thinking about  decision-making under uncertainty.