Episode 408: Elroy Dimson - Investing & Optimism
The Rational Reminder Podcast · 2026-05-07 · 1h 14m
Episode notes
In this episode, we are joined by Elroy Dimson, Professor of Finance at Cambridge Judge Business School and co-creator of the Dimson-Marsh-Staunton (DMS) dataset, for a sweeping and deeply insightful conversation on financial history, market behavior, and the evolution of global investing. Elroy walks us through the origins of the groundbreaking Triumph of the Optimists, the challenges of assembling over 100 years of global return data, and the critical biases that once shaped our understanding of markets. We explore how expanding beyond U.S.-centric data reshaped expectations for the equity risk premium, why economic growth doesn't necessarily translate into higher stock returns, and what history reveals about diversification, factor investing, and investor behavior. Elroy also shares lessons from his work with major institutions like Norway's sovereign wealth fund, discusses the surprising long-term outperformance of railways, and offers a grounded perspective on future expected returns. This episode is a masterclass in using history to inform better financial decisions. Key Points From This Episode: (0:04:00) Introduction to Elroy Dimson and the significance of the DMS dataset.