Covered Calls Uncovered Roni Israelov and Lars N
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Financial Analysts Journal Volume 71 · Number 6 ©2015 CFA Institute Covered Calls Uncovered Roni Israelov and Lars N. Nielsen Typical covered call strategies collect the equity and volatility risk premiums but also embed exposure to a naive equity reversal strategy that is uncompensated. This article presents a novel risk and performance attribu- tion methodology that deconstructs the strategy into these three exposures. Historically, the equity exposure contributed most of the risk and return. The short volatility exposure realized a Sharpe ratio of nearly 1.0 but contributed only 10% of the risk. The equity reversal exposure contributed approximately 25% of the risk but provided little return in exchange. The authors propose a risk-managed covered call strategy that eliminates the uncompensated equity reversal exposure. This modified covered call strategy has a superior Sharpe ratio, reduced volatility, and reduced downside equity beta. quity index covered calls are the most easily by natural buyers can lead to a risk premium. accessible source of the volatility risk pre- Litterman (2011) suggested that long-term inves- Emium for most investors.1 The volatility risk tors, such as pensions and endowments, should be premium, which is absent from most investors’ port- natural providers of financial insurance and sellers folios, has had more than double the risk-adjusted of options. returns (Sharpe ratio) of the equity risk premium, Yet, many investors remain skeptical of covered which is the dominant source of return for most call strategies. Although deceptively simple—long investors. By providing the equity and volatility equity and short a call option—covered calls are not risk premiums, equity index covered calls’ returns well understood. Israelov and Nielsen (2014) identi- have been historically attractive, nearly matching the fied and dispelled eight commonly circulated myths returns of their underlying indexes with significantly about covered calls. These myths sound plausible; lower volatility.2 otherwise, they would not have such longevity. But Options are a form of financial insurance, and they can be a problem if they affect portfolio con- the volatility risk premium is compensation paid by struction decisions. The securities overwritten and option buyers to the option sellers who underwrite the strikes and maturities of the call options that this insurance. Bakshi and Kapadia (2003) analyzed are sold should be explicitly selected to achieve the delta-hedged option returns to show that equity portfolio’s allocation to the equity and volatility risk index options include a volatility risk premium. premiums without taking unnecessary risk. Price Bollen and Whaley (2004) and Gârleanu, Pedersen, targets, downside protection, and income generation and Poteshman (2009) showed how option demand are diversions. One source of confusion on covered calls may be Roni Israelov is vice president and Lars N. Nielsen is due to the opacity of the strategy’s risk exposures. principal at AQR Capital Management, Greenwich, Our article’s first contribution is a novel performance Connecticut. attribution methodology for portfolios holding Editor’s note: Roni Israelov and Lars N. Nielson man- options, such as the covered call strategy. We dem- age option portfolios and covered calls at AQR Capital onstrate how to decompose the portfolio return into Management and may have a commercial interest in three distinct risk exposures: passive equity, equity the topics discussed in this article. market timing, and short volatility. Editor’s note: This article was reviewed and accepted Our performance attribution methodology pro- by Executive Editor Robert Litterman. vides investment managers with a tool to effectively and transparently communicate their strategy’s Authors’ note: The views and opinions expressed herein are those of the authors and do not necessarily reflect performance to their investors and allows investors the views of AQR Capital Management, LLC (“AQR”), to properly place the covered call’s risk exposures its affiliates, or its employees, nor do they constitute an and returns in the context of their overall portfolios. offer, a solicitation of an offer, or any advice or recom- Further, it provides a framework by which portfolio mendation to purchase any securities or other financial managers can evaluate the impact of strike, maturity, instruments by AQR. underlying security selection, risk management, and 44 www.cfapubs.org © 2015 CFA Institute. All rights reserved. Covered Calls Uncovered leverage on their strategy’s risk and returns. Proper however, do not hedge the time-varying equity expo- performance attribution facilitates improved port- sure arising from option convexity. Further, the risk folio construction. and return contribution of an unhedged short option For example, selling at-the-money options is position’s dynamic equity exposure is by and large expected to provide the highest exposure to short not reported by those who manage to those who volatility. Covered call strategies that sell low-strike invest in covered call strategies and is unaddressed options have less equity exposure than those that in the covered call literature. sell high-strike options. The risk-adjusted perfor- We use our performance attribution to docu- mance of short volatility may be higher for low-strike ment that market timing is responsible for about options because of the implied volatility smile that one-quarter of the at-the-money covered call’s risk. is in part due to demand for portfolio protection. The timing bet is smallest immediately after option By attributing the covered call’s performance to its expiration and largest just prior to option expiration. underlying exposures, a portfolio may be explicitly In fact, on the day before the call option expires, the constructed to achieve specific objectives. equity timing position provides on average nearly Although we use our performance attribu- the same risk as the passive equity exposure. We tion to better understand covered call strategies, further show that covered call investors have not it may be more broadly applied to any portfolio been compensated for bearing this risk. Because the that includes options. The returns of these portfolios embedded market timing is hedgeable by trading may be attributed to their passive and time-varying the underlying equity, covered call investors do equity exposures and to their volatility exposure. not need to take that bet to earn the volatility risk For example, protected strategies that are long an premium. In other words, by shorting an option, index and long a protective put option typically covered calls include a market-timing exposure have significantly lower returns than their under- that bets on equity reversals whose risk is mate- lying index. Our performance attribution would rial, uncompensated, and unnecessary for earning indicate the long volatility’s contribution to the the volatility risk premium. strategy’s performance degradation and how much Having identified the covered call’s active less equity risk premium has been earned owing equity exposure as an uncompensated contributor to the put option’s average negative equity expo- to risk, our final contribution is the analysis of a risk- sure. In a similar manner, Israelov and Klein (2015) managed covered call strategy that hedges away applied our performance attribution to explain the the identified dynamic equity exposure. On each risk and return characteristics of a more complex day, the covered call’s active equity exposure may option portfolio—an equity index collar strategy be measured by computing the delta of the strategy’s that is long an index, short a call option, and long call option. The strategy trades an offsetting amount a protective put. of the S&P 500 Index so that the covered call’s equity ■ Discussion of findings. We demonstrate our exposure remains constant. This risk management proposed performance attribution by analyzing exercise mimics the delta-hedging approach taken and comparing two covered call strategies. The by volatility desks. In so doing, the risk-managed first strategy mimics the CBOE S&P 500 BuyWrite covered call achieves higher risk-adjusted returns Index (BXM), selling one-month at-the-money than does the traditional covered call because it call options on option expiration dates. The sec- continues to collect the same amount of equity and ond strategy mimics the CBOE S&P 500 2% OTM volatility risk premiums but is no longer exposed to BuyWrite Index (BXY), selling one-month 2% out- equity market-timing risk. The risk-managed strat- of-the-money call options on option expiration egy improved the covered call Sharpe ratio from 0.37 dates. Our performance attribution shows that to 0.52 by reducing its annualized volatility from passive equity is the dominant exposure for both 11.4% to 9.2%. covered call strategies. Short volatility contributes The risk-managed covered call has an addi- less than 10% of the risk but, with a Sharpe ratio tional benefit beyond improving risk-adjusted near 1.0, adds approximately 2% annualized return returns. The strategy’s goal, design, and execu- to the covered call strategies. tion are clear, and they transparently map to its Option-savvy market participants, such as performance. The strategy seeks to collect equity market makers, are well aware that options include and volatility risk premiums and does so by being market timing, an active equity exposure. In fact, long equity and short volatility. We may explicitly they often use a delta-hedging program specifically construct a portfolio by choosing how much risk designed to reduce the risk arising from this dynamic to allocate to the two desired exposures and sub- exposure. The covered call benchmark (CBOE S&P sequently measure their resulting contributions to 500 BuyWrite Index) and most covered call funds, the strategy’s performance. November/December 2015 www.cfapubs.org 45 Financial Analysts Journal Covered Call Performance is $100. We may take the long equity exposure and Attribution split it in half. Panel A depicts a portfolio that owns $50 of equity and $50 of cash.