Covered Calls: Risk-Managed Yield Enhancement

Covered Calls: Risk-Managed Yield Enhancement

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The Elegance of the Option: Revisiting Basic Principles

Financial derivatives, such as options, have been part of the economic landscape since ancient times, often serving as mechanisms for managing risk (Bodie, Merton, and Cleeton, 2008). The covered call is a specific option strategy, hinged on the sale of call options against a held stock position. This strategy, integration of the foundational principles of derivatives and equity investment, offers an intriguing risk-return proposition to consider. The sale of a call option provides the holder the right but not the obligation to buy an underlying asset at a specific price (the strike price) before a specific time (the expiry date). The seller, or writer, of the option, is obligated to fulfill this contract if the holder exercises their right. This is the crux of a call option, as detailed by Hull (2017).

Understanding the payoff structure of a call option is essential. In the words of Black and Scholes (1973), “The call option is a bet on the price of the underlying asset rising.” If the stock price remains below the strike price at expiration, the option will expire worthless, and the writer will retain the premium as income. However, if the stock price rises above the strike price, the holder will exercise the option, and the writer will be obligated to sell the stock at the strike price.

Call Option Pay-off Diagram

Anatomy of a Covered Call Strategy: Yield Augmentation and Risk Mitigation

Now, let’s turn our attention to the covered call strategy, an income-oriented approach derived from the basic option structure. Writing a covered call means selling a call option on an underlying asset that the writer already owns. This is in contrast to writing naked calls, which involves selling call options without owning the underlying asset, a strategy characterized by a significantly higher risk profile (Chance and Brooks, 2015).

Covered call writing provides two main sources of return: the premium income from selling the call option and the potential capital gain from the underlying asset. A key advantage of this strategy, as illustrated by Whaley (2002), is that it allows investors to generate additional income from their portfolio while providing a degree of downside protection through the premium received. This makes it an attractive strategy in a flat or slightly rising market.

However, there’s a trade-off: the upside potential is capped. If the stock price rises above the strike price, the holder will exercise the option, and the writer will have to sell the stock at the strike price. The writer will miss out on any additional gain beyond the strike price, although they still benefit from the capital gain up to the strike price and the premium income (Merton, 1998).

The Empirical Evidence: Covered Calls in Practice

Historically, empirical evidence suggests that covered call strategies have offered attractive risk-adjusted returns. According to a study by Szado (2009), covered call strategies tended to outperform their benchmark indices in terms of both total return and Sharpe ratio during the 20-year period from 1988 to 2008. The Sharpe ratio is especially pertinent in this context as it allows investors to understand the return of an investment compared to its risk. Essentially, the higher the value of the Sharpe ratio, the more attractive the risk-adjusted return. Thus, the superior Sharpe ratio of covered calls during this period signifies a more beneficial risk-to-reward trade-off.

Moreover, research by Fedyk, Johnson, and Xu (2018) confirms that covered call writing can enhance portfolio yield without dramatically increasing risk. Their findings suggest that the premium income can provide a buffer against potential losses in the underlying stock, reducing portfolio volatility and helping to improve the risk-return trade-off.

However, it’s essential to bear in mind the limitations of the strategy. A covered call strategy is not designed to provide protection in a sharply declining market, and the income from the premium might not be sufficient to offset substantial capital losses in such scenarios (Black, 1975). It’s also important to note that it requires continuous monitoring and adjustment, as described by Whaley (2002).

S&P500 returns v.s. BXM Covered Call returns, 1987- 2009

Theoretical Perspectives: Economic Implications and Optimal Utilization

A deeper exploration into the economic theory surrounding covered calls exposes the multifaceted nature of this strategy. Cox and Rubinstein (1985) pointed out that covered call writing effectively converts a non-linear payoff into a linear one, making the risk-return profile more akin to that of a bond than a stock.

This notion is particularly crucial when considering the optimal utilization of covered calls. As argued by Merton (1973), in an ideal world of frictionless markets, there would be no need for covered call strategies. Investors could create the same payoff structure through dynamic trading strategies involving only the underlying asset and a risk-free bond.

However, in the real world, frictions such as transaction costs and taxes do exist. Therefore, covered calls can serve as a convenient and cost-effective way for investors to achieve a bond-like payoff with equity-like returns (Brennan and Schwartz, 1979). They can be particularly useful for risk-averse investors seeking to generate regular income from their equity investments or for institutional investors managing large equity portfolios (Black and Scholes, 1973).

Integrating Theory with Practice

Covered call writing embodies the intersection of theoretical constructs with pragmatic market application. It’s an elegant strategy that allows investors to tap into the inherent potential of options as risk management tools while simultaneously enhancing portfolio yields. Yet, like any financial strategy, covered calls come with their share of caveats and nuances. Investors must account for market conditions, transaction costs, tax implications, and their personal risk-return objectives before embarking on this strategy. An in-depth understanding of the mechanics of options, along with meticulous monitoring, is essential to employ this strategy effectively. The covered call, therefore, stands as a testament to the ingenuity of financial engineering. It highlights how a sophisticated understanding of derivative contracts can be used to sculpt risk and return profiles to fit the diverse needs of investors in an ever-evolving market landscape.


Black, F., & Scholes, M. (1973). The pricing of options and corporate liabilities. Journal of Political Economy, 81(3), 637-654.

Bodie, Z., Merton, R. C., & Cleeton, D. L. (2008). Financial economics (2nd ed.). Pearson.

Brennan, M. J., & Schwartz, E. S. (1979). The pricing of equity-linked life insurance policies with an asset value guarantee. Journal of Financial Economics, 3(3), 195-213.

Chance, D. M., & Brooks, R. (2015). Introduction to derivatives and risk management (10th ed.). Cengage Learning.

Cox, J. C., & Rubinstein, M. (1985). Options markets. Prentice-Hall.

Fedyk, T., Johnson, T. C., & Xu, M. (2018). The economics of option trading by retail investors. Management Science, 64(12), 5743-5760.

Hull, J. C. (2017). Options, futures, and other derivatives (10th ed.). Pearson.

Merton, R. C. (1973). Theory of rational option pricing. The Bell Journal of Economics and Management Science, 4(1), 141-183.

Szado, E. (2009). Defining the covered call. Journal of Trading, 4(1), 28-39.

Whaley, R. E. (2002). Risk and return of the CBOE buywrite monthly index. The Journal of Derivatives, 10(2), 35-42.