Though the profound importance of the market risk premium to finance is unquestioned, its actual measurement has been problematic for both academics and analysts alike. What exactly is the magnitude of the ex post market risk premium? What is its relationship with the expected or ex ante premium? Though finance theory estimates an historical equity premium of 1-2%, simple arithmetic averaging of historical data gives a greater mean of 5-6%, an anomaly known as the equity premium puzzle. More recent findings provide a still greater equity premium point estimate. This paper explores the hypothesis that statistical misspecification of historical equity premium data may be an important contributing factor for such contradictions.

In 2001, Martin Leibowitz organized an Equity Risk Premium (ERP) Forum for CFA Institute, in which the participants discussed issues related to the ERP and made estimates for the future. This forum was repeated by Leibowitz, Brett Hammond, and Laurence Siegel in 2011, setting a precedent for a decennial forum. Siegel organized and moderated the discussion in 2021, and the proceedings from that event make up the current book. The participants in 2021 were (in alphabetical order) Robert Arnott, Clifford Asness, Mary Ida Compton, Elroy Dimson, William Goetzmann, Roger Ibbotson, Antti Ilmanen, Martin Leibowitz, Rajnish Mehra, Thomas Philips, and Jeremy Siegel. Each participant made a presentation, which was then discussed by the whole group. Finally, a roundtable discussion involving all of the participants was moderated by Laurence Siegel. Ibbotson and Dimson discussed historical returns in different countries. Ibbotson focused on the United States, while Dimson took a global industrial-country view. The history goes back almost a century (Ibbotson) or more than a century (Dimson), providing a look at how returns have evolved over a wide variety of conditions. Ibbotson also presented his method for making probabilistic forecasts of returns. Dimson, who is British, showed that “American exceptionalism” is one way to understand the results. Asness looked at the effectiveness of Robert Shiller’s CAPE (cyclically adjusted price-earnings ratio) valuation measure for forecasting. Valuations rose over the period he studied, and a lively discussion was had about why this may have occurred. Arnott focused on the growth rate of dividends, which has been very slow in per-share terms, and argued (with much debate from the other participants) that buybacks are only a partial substitute for dividends. Leibowitz, also looking at valuation as the lodestone of return forecasts, set forth a “growth adjustment” that brought his forecast in line with those made by others. Compton, a consultant to pension plans, discussed the challenges of communicating lower expected returns to clients. She also emphasized that expected returns “don’t always come true,” they’re just someone’s best forecast. Ilmanen broke up the expected return into its component parts: dividends, real growth, inflation, and so forth. Doing this, he said, allows one to debate the estimates for each part and ascertain how accurate each of the estimates is. Philips started by presenting a method for forecasting bond returns. He then turned to equities, for which he compared forecasts with subsequent realizations using a variety of forecast methods. Mehra discussed a number of issues related to the existence of premiums (equity risk, value, small cap, and so forth) and concluded that, although some of these are unstable, the ERP is highly stable. Jeremy Siegel advocated a “back to basics” approach using dividend and earnings yields, dividend and earnings growth rates, payout ratios, and price-to-earnings ratios. He emphasized that earnings can be calculated in a number of different way, and said that accounting practices have become more conservative over the years. Goetzmann concluded the session by reporting that one company, a water mill in France, had almost 600 years of historical return data and that an asset pricing model could be tested using those data. According to this model, the stock price is the present value of expected future dividends and is supported by the evidence. In sum, because of high valuations and low interest rates, the participants expect lower total returns in the future than in the past. A forward-looking ERP of 4% to 5% was the consensus of the group.

Das Thema Risikoprämie für Aktien (Equity Risk Premium) wird hier zum ersten Mal verständlich erklärt. Die Risikoprämie für Aktien stellt einen Renditeausgleich dar für das erhöhte Risiko, das ein Anleger bei der Investition in Aktien eingeht, im Vergleich zu einer Investition in risikofreie Staatsanleihen. Die Risikoprämie ist zwar von der Theorie her einfach, jedoch in der Praxis ein sehr komplexes Phänomen. Für Finanzentscheidungen ist es von größter Bedeutung, daß man das Prinzip der Risikoprämie versteht und es anwenden kann. Cornell erläutert das Thema Schritt für Schritt sehr anschaulich und ohne terminologischen Ballast. Zunächst wird die Risikoprämie im Zusammenhang mit der Geschichte des Aktienmarktes betrachtet. Der Haussemarkt der 90er dient dabei als Fallstudie. Cornell zeigt, welche Rückschlüsse man durch die Analyse der Risikoprämie im historischen Verlauf für den Aktienmarkt ziehen kann, z.B. ob Aktienkurse steigen oder fallen oder ob sich der Aktienmarkt verändert. Vorausschauende Schätzungen der Risikoprämie werden anhand verschiedener konkurrierender Modelle analysiert, wobei die Vorzüge der jeweiligen Methode mitbewertet werden. 'Equity Risk Premium' ist das erste Buch, das dieses wichtige Prinzip der Risiko-Nutzen-Analyse erschöpfend behandelt. Es vermittelt einen tiefen Einblick und deckt alle Grundlagen ab, damit Investoren fundierte Finanzentscheidungen treffen können. Ein absolutes Muß für institutionelle Anleger, Geldmanager und Finanzvorstände, die auf eine fundierte Marktanalyse zurückgreifen müssen. (06/99)

This volume offers contributions to questions relating to the economics of innovation and technological change. Central to the development of new technologies are institutional environments and among the topics discussed are the roles played by universities and the ways in which the allocation of funds affects innovation.

A radical, definitive explanation of the link between loss aversion theory, the equity risk premium and stock price, and how to profit from it The Risk Premium Factor presents and proves a radical new theory that explains the stock market, offering a quantitative explanation for all the booms, busts, bubbles, and multiple expansions and contractions of the market we have experienced over the past half-century. Written by Stephen D. Hassett, a corporate development executive, author and specialist in value management, mergers and acquisitions, new venture strategy, development, and execution for high technology, SaaS, web, and mobile businesses, the book convincingly demonstrates that the equity risk premium is proportional to long-term Treasury yields, establishing a connection to loss aversion theory. Explains stock prices from 1960 through the present including the 2008/09 "market meltdown" Shows how the S&P 500 has consistently reverted to values predicted by the model Solves the equity premium puzzle by showing that it is consistent with findings on loss aversion Demonstrates that three factors drive valuation and stock price: earnings, long term growth, and interest rates Understanding the stock market is simple. By grasping the simplicity, business leaders, corporate decision makers, private equity, venture capital, professional, and individual investors will fully understand the system under which they operate, and find themselves empowered to make better decisions managing their businesses and investment portfolios.

The recent collapse of the stock market has refocused attention on the question of the equity risk premium. One of the most comprehensive studies of the equity premium, completed by Fama and French in 2000, is now significantly out of date and requires refreshing. This article provides that update. We find that various procedures for estimating the premium from historical data are now converging to an annual equity premium over short-term commercial paper on the order of four percent.