Low Volatility Anomaly
The Low Volatility Anomaly is a fascinating and counterintuitive phenomenon observed in financial markets, where securities with lower risk (or volatility) tend to outperform those with higher risk over the long term. This observation contradicts the traditional finance theory, particularly the Capital Asset Pricing Model (CAPM), which posits a direct relationship between risk and expected return—higher risk should theoretically be compensated by higher returns. The Low Volatility Anomaly has generated considerable interest among researchers, academics, and practitioners, leading to the development of various investment strategies aiming to exploit this anomaly.
Understanding Volatility and Risk
Definitions
- Volatility: Volatility refers to the degree of variation of an asset’s returns over time, which is commonly measured by the standard deviation or variance of returns. High volatility indicates large price swings, whereas low volatility signifies more stable prices.
- Risk: In the context of investment, risk often refers to the uncertainty regarding the returns an investment might produce. Risk is typically quantified by measures like standard deviation, variance, Value at Risk (VaR), and beta (a measure of a stock’s volatility relative to the market).
Traditional Finance Theory
In traditional finance theory rooted in the CAPM, risk and return are linearly related. The model suggests that investors should expect higher returns as compensation for taking on higher risk. According to the CAPM:
[ \text{Expected Return} = R_f + [beta](../b/beta.html) ( R_m - R_f ) ]
Where:
- ( R_f ) is the risk-free rate,
- ( R_m ) is the expected market return,
- ( [beta](../b/beta.html) ) is the measure of a stock’s volatility in relation to the market.
The Anomaly
Contrary to the CAPM, empirical evidence shows that portfolios of low-volatility stocks have historically delivered higher risk-adjusted returns than portfolios of high-volatility stocks. This is surprising because it implies that investors can achieve superior returns without taking on higher risk.
Historical Evidence
Early Research
The Low Volatility Anomaly was first documented by Robert Haugen and James Heins in the 1970s. They found that low-volatility stocks had higher average returns and lower risk compared to high-volatility stocks, challenging the prevailing market efficiency hypothesis.
Subsequent Studies
Numerous studies have since confirmed and expanded upon these findings. For instance:
- Baker, Bradley, and Wurgler (2011) found that low-volatility stocks outperformed high-volatility ones across 33 developed and emerging markets.
- Ang, Hodrick, Xing, and Zhang (2006) examined U.S. stock returns and discovered that low-volatility stocks consistently generated higher risk-adjusted returns than their high-volatility counterparts.
Global Perspective
The Low Volatility Anomaly is not confined to any single market; it has been observed globally across different asset classes, including equities, bonds, and commodities.
Explanations for the Anomaly
Behavioral Finance
Several behavioral finance theories have been proposed to explain the Low Volatility Anomaly:
- Lottery Preferences: Investors may overpay for high-volatility stocks with lottery-like payoff characteristics, expecting large gains despite their low probability. This leads to an overvaluation of high-volatility stocks and undervaluation of low-volatility ones.
- Overconfidence: Overconfident investors may prefer volatile stocks, believing they can time the market or select outperforming stocks, thereby pushing up prices of high-volatility stocks.
- Benchmarking and Career Concerns: Fund managers often benchmark their performance against market indices. To avoid underperformance relative to the benchmark, they might overweight high-volatility stocks, which can move more sharply and quickly, hoping to match or exceed market returns. This inflates the prices of high-volatility stocks and depresses the prices of low-volatility stocks.
Market Structure
Market structure-related reasons also contribute to the Low Volatility Anomaly:
- Leverage Constraints: Many institutional investors face constraints on the use of leverage. Since low-volatility stocks naturally offer lower returns, these investors may avoid them in favor of riskier, higher-return stocks. This preference drives up the prices of high-volatility stocks and suppresses those of low-volatility ones.
- Institutional Mandates: Investment mandates and guidelines might prevent certain investors from fully exploiting low-volatility opportunities. For instance, many funds are mandated to stay fully invested, limiting their ability to tilt heavily toward low-volatility stocks.
Investment Strategies
Low Volatility Strategies
Investment strategies based on the Low Volatility Anomaly typically involve constructing portfolios of low-volatility stocks with the expectation of achieving higher risk-adjusted returns. Some common approaches include:
- Minimum Volatility Portfolios: These portfolios are constructed to minimize total portfolio volatility. This approach may involve using mathematical optimization techniques to select a combination of stocks that produce the lowest possible volatility for a given return level.
- Risk Parity: This strategy divides investment capital among asset classes such that each contributes equally to the overall portfolio risk. It often results in a significant allocation to low-volatility assets.
- Low-Volatility Factor Investing: This approach involves selecting stocks based on their volatility characteristics, often using factors like historical volatility or beta to identify low-volatility candidates.
ETF and Fund Offerings
Many financial institutions offer products designed to exploit the Low Volatility Anomaly, including Exchange-Traded Funds (ETFs) and mutual funds. Some notable examples include:
- iShares Edge MSCI Minimum Volatility USA ETF (USMV): This ETF aims to provide exposure to U.S. stocks with lower volatility characteristics.
- Invesco S&P 500 Low Volatility ETF (SPLV): This ETF focuses on the 100 least volatile stocks in the S&P 500 Index.
- PowerShares S&P International Developed Low Volatility Portfolio (IDLV): This ETF targets low-volatility stocks in developed markets outside the U.S.
Performance and Drawbacks
Performance
Low-volatility strategies have generally performed well, particularly during periods of market stress or downturns. They tend to exhibit less drawdown and provide a smoother return profile compared to high-volatility strategies.
Drawbacks
Despite their advantages, low-volatility strategies are not without drawbacks:
- Underperformance in Bull Markets: In strongly rising markets, low-volatility stocks may underperform their high-volatility counterparts as risk appetite increases and investors chase higher returns.
- Sector Concentration: Low-volatility portfolios may become concentrated in certain sectors, such as utilities or consumer staples, which typically exhibit lower volatility.
- Limited Upside: While low-volatility strategies aim to provide better risk-adjusted returns, they may offer limited upside potential during rapid market upswings.
Future Prospects
The enduring nature of the Low Volatility Anomaly suggests it is likely to persist, but ongoing research is essential for better understanding its underlying causes and for refining investment strategies. Furthermore, as more investors become aware of and seek to exploit the anomaly, its efficacy could diminish over time due to increased competition and market efficiency.
For more information on companies and products related to low-volatility investing, you can visit the following links: