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On ESG: Theory and Empirics

Paper Session

Sunday, Jan. 9, 2022 3:45 PM - 5:45 PM (EST)

Hosted By: American Finance Association
  • Chair: Stuart Gillan, University of North Texas

ESG Confusion and Stock Returns: Tackling the Problem of Noise

Florian Berg
,
Massachusetts Institute of Technology
Julian Koelbel
,
Massachusetts Institute of Technology
Anna Pavlova
,
London Business School
Roberto Rigobon
,
Massachusetts Institute of Technology

Abstract

How strongly does ESG (environmental, social and governance) performance affect stock returns? Answering this question is difficult because existing measures of performance, ESG ratings, are noisy. To tackle the bias, we propose a noise-correction procedure, in which we instrument ESG ratings with ratings of other ESG rating agencies, as in the classical errors-in-variables problem. The corrected estimates demonstrate that the effect of ESG performance on stock returns is stronger than previously estimated; the standard regression estimates of ESG ratings' impact on stock returns are biased downward by about 60%. Our dataset includes scores of eight ESG rating agencies for firms located in North America, Europe, and Japan. We determine which agencies’ scores are valid instruments (not all of them are) and estimate the noise-to-signal ratio for each ESG rating agency (some of which are very large). Overall, our results suggest that it is advantageous to rely on several complementary ratings. In our sample, stocks with higher ESG performance have higher expected returns. Our model provides several explanations for this finding.

The Cost of ESG Investing

Laura Lindsey
,
Arizona State University
Seth Pruitt
,
Arizona State University
Christoph Schiller
,
Arizona State University

Abstract

Even against increasing interest in socially responsible investing mandates, we find that implementing ESG strategies can cost nothing. Modifying optimal portfolio weights to achieve an ESG-investing tilt negligibly affects portfolio performance across a broad range of ESG measures and thresholds. This is because those ESG measures do not provide information about future stock performance, either in relation to risk or mispricing, beyond what is provided by other observable firm characteristics. That the stock market does not reflect significant equilibrium pricing of ESG information is rationalized in a model of responsible investing wherein investors differ in which ESG-related criteria are used to weight their portfolios.

Quantifying the Impact of Impact Investing

Andrew Lo
,
Massachusetts Institute of Technology
Ruixun Zhang
,
Peking University

Abstract

We propose a quantitative framework for assessing the financial impact of any form of impact investing, including socially responsible investing (SRI), environmental, social, and governance (ESG) objectives, and other non-financial investment criteria. We derive conditions under which impact investing detracts from, improves on, or is neutral to the performance of traditional mean-variance optimal portfolios, which depends on whether the correlations between the impact factor and unobserved excess returns are negative, positive, or zero, respectively. Using Treynor-Black portfolios to maximize the risk-adjusted returns of impact portfolios, we propose a quantitative measure for the financial reward, or cost, of impact investing compared to passive index benchmarks. We illustrate our approach with applications to biotech venture philanthropy, divesting from “sin” stocks, investing in ESG, and “meme” stock rallies such as GameStop in 2021.

Dissecting Green Returns

Lubos Pastor
,
University of Chicago
Robert Stambaugh
,
University of Pennsylvania
Lucian Taylor
,
University of Pennsylvania

Abstract

Green assets delivered high returns in recent years. This performance reflects unexpectedly strong increases in environmental concerns, not high expected returns. German green bonds outperformed their higher-yielding non-green twins as the “greenium” widened, and U.S. green stocks outperformed brown as climate concerns strengthened. To show the latter, we construct a theoretically motivated green factor—a return spread between environmentally friendly and unfriendly stocks—and find that its positive performance disappears without climate-concern shocks. A theory-driven two-factor model featuring the green factor explains much of the recent underperformance of value stocks. Our evidence also suggests small stocks underreact to climate news.

Sustainable Systematic Credit

Peter Diep
,
AQR Capital Management
Lukasz Pomorski
,
AQR Capital Management
Scott Richardson
,
AQR Capital Management

Abstract

Interest in sustainable investing has exploded in recent years, initially focused on public equity markets, but now evolving into fixed income. We assess various aspects of sustainable investing for developed market corporate bond markets (both Investment Grade and High Yield). Using a representative set of sustainability measures spanning environment, societal and governance (ESG) constructs we find: (i) credit spreads are only marginally associated with ESG measures, (ii) ESG measures are only marginally associated with standard return forecasting measures for corporate bonds, (iii) ESG measures are not reliably associated with future credit excess returns, and (iv) ESG measures are negatively associated with the future volatility of credit excess returns. While the direct investment impact of sustainability is modest, there is still considerable interest from asset owners to ensure credit allocations are sustainable. We find that it is possible to incorporate (i) both static and dynamic exclusion screens, (ii) positive tilts toward more sustainable issuers, and (iii) economically meaningful reduction in carbon intensity, with minimal portfolio distortions. Thus, a well-implemented systematic approach has the potential to offer attractive risk-adjusted returns in a sustainable manner.
JEL Classifications
  • G0 - General