How to Measure Your Portfolio's Risk-Adjusted Performance

Fajasy
Updated: September 26, 2023

Contents

In this article, I will show you how to measure your portfolio's risk-adjusted performance. While many investors often focus on calculating the total return over a period of time, inclusive of capital gains, dividends, interest, and/or distributions, this only paints half the picture. Further, simply comparing your portfolio's performance to a benchmark might give you a sense of how well you're doing, but it doesn't provide a comprehensive view of the risks you've taken to achieve those returns.

Risk-adjusted performance metrics delve deeper, allowing you to understand not just the rewards, but the risks associated with your investment choices. By the end of this article, you'll have a clearer understanding of why looking solely at returns can be misleading and how the risk metrics discussed will provide the other half of the story, ensuring a holistic view of your investment's performance.

To illustrate each metric, we will present three portfolio examples in tabular format. This practical approach allows for easy application to your own investment portfolios.

Understanding Risk-Adjusted Performance

Risk-adjusted performance is a fundamental concept in portfolio management. It's essential for investors to comprehend the returns they anticipate or have achieved relative to the associated risks. This section provides a brief overview of the principles of risk-adjusted performance and its importance in managing portfolios.

What is Risk-Adjusted Performance?

Risk-adjusted performance assesses the returns of an investment portfolio while factoring in the associated risks. It goes beyond mere returns, examining the level of risk undertaken to achieve them. This approach allows investors to make apples-to-apples comparisons between different investments, irrespective of their risk profiles. For example, while two portfolios might both show similar returns, if one exhibits greater volatility, it may be less appealing than another with more consistent returns.

Why is Measuring Risk-Adjusted Performance Important?

Measuring risk-adjusted performance is important for several reasons:

  1. Informed Decision Making: Provides investors with a clearer picture of the returns they can expect relative to the risks they are taking.
  2. Comparative Analysis: Allows for a more apples-to-apples comparison between different investment opportunities.
  3. Risk Management: Helps investors understand the volatility of their portfolio and whether it aligns with their risk tolerance and investment goals.
  4. Performance Evaluation: Enables investors to assess how well a portfolio manager or investment strategy is performing, considering the risks involved.

Evaluating Portfolio Performance

Metrics like Alpha and the Information Ratio provide a lens into how a portfolio measures up against its benchmark and its relative standing. This section explores these key indicators and their impact on portfolio management.

Alpha

Alpha (aka Jensen's Alpha) is a metric that measures an investment's performance over a specific time period relative to a benchmark, often an index like the S&P 500. It quantifies how much a security or portfolio has outperformed or underperformed this benchmark, once adjusted for beta. In essence, if the market's excess return is zero, alpha can be interpreted as the security's expected excess return. This means alpha encapsulates the anticipated return on a security beyond the risk-free rate and any returns driven by market movements.

For those whose investment portfolios aim to outperform a different benchmark other than the S&P 500, alpha can be computed in relation to that chosen benchmark. Beyond its primary definition, alpha also serves as an indicator of the value a portfolio manager adds or detracts. A portfolio with a positive alpha has outperformed its benchmark, considering the risk taken, while a negative alpha denotes underperformance.

The formula for Alpha is shown below:

Alpha (α) = Rp - [Rf + β(Rm - Rf)]

where:

  • α = Alpha
  • Rp = Portfolio's expected return
  • Rf = Risk-free rate
  • β = Beta (systematic risk of portfolio)
  • Rm = Market's expected return

For investors, alpha is an important metric, providing insight on a manager's proficiency or the efficacy of a specific investment strategy. An alpha of 1.0 signifies that the portfolio has surpassed its benchmark by 1%, while an alpha of -1.0 denotes underperformance by 1%.

Below is a table detailing the components of Alpha for three distinct portfolios:

Notably, from the table above, Portfolio B, with a beta of 1.0, aligns with the market on a risk-adjusted basis (alpha of 0%). In contrast, Portfolio A, with a beta of 0.9, indicates less volatility than the market and yields a positive alpha of 0.2%. Thus, while both portfolios yield the same overall return, Portfolio A achieves it with reduced volatility, making it a more efficient choice for risk-adjusted performance.

Information Ratio

The Information Ratio assesses the risk-adjusted performance of a portfolio relative to a selected benchmark. It is determined by computing the difference between the portfolio's average return and that of the benchmark, and then dividing this by the tracking error. This tracking error, or "active risk," quantifies the consistency between the portfolio's returns and the benchmark's by measuring their standard deviation difference. In essence, the Information Ratio not only gauges how a portfolio's returns align with its benchmark but also provides investors with a perspective on a manager's ability to deliver consistent returns, factoring in the portfolio's inherent volatility.

The Information Ratio formula is shown below:

Information Ratio = (Rp - Rb) / σe

where:

  • Rp = portfolio's expected return
  • Rb = benchmark's return
  • σe = tracking error (volatility of portfolio return relative to benchmark return)

A portfolio manager could opt for a passive strategy, such as replicating the index, which would result in a tracking error close to zero. If the Information Ratio is negative, it indicates that the portfolio underperformed the selected benchmark during the specified period. Conversely, a higher Information Ratio is preferable as it signifies better performance relative to the benchmark.

The Information Ratio is really only useful when a clear benchmark for the portfolio is identifiable. For portfolios operated independently of any benchmark, the Information Ratio might not provide meaningful insights.

Below is a table detailing the components of the Information Ratio for three distinct portfolios:

As the table above shows, Portfolio A offers the best risk-adjusted performance relative to the benchmark, while Portfolio C might warrant a review of its investment strategy given its underperformance. Portfolio B, on the other hand, simply tracks the benchmark.

Assessing Portfolio Risk

Risk assessment is a multifaceted endeavor. By exploring metrics like Standard Deviation, Historical Maximum Drawdowns, and Value at Risk, investors can gain a comprehensive understanding of the potential volatility and downside risks inherent in their portfolios.

Standard Deviation

Standard deviation serves as a crucial instrument to assess the potential risk and upside of any given stock. It quantifies the degree to which a dataset diverges from its mean, thereby illustrating the dispersion of data. This measure provides a nuanced view of the distribution of data, enabling more informed investment decisions. Utilizing standard deviation is essential as relying solely on average return performance can be insufficient for comprehensive risk assessment and portfolio management.

The formula for standard deviation is shown below:

Standard Deviation (σ) = √[ Σ ( Xi - μ )² / N ]

where:

  • σ = Standard deviation
  • Σ = The sum of all
  • Xi = Each individual value in the dataset
  • μ = The mean or average value of the dataset
  • N = The number of values in the dataset

A higher standard deviation indicates greater potential risk, making it essential for understanding portfolio return fluctuations over time. However, its effectiveness is limited in scenarios with non-normally distributed returns, very short-term investments, or when a focus on downside risk is paramount. In such cases, alternative metrics like Value at Risk (VaR) (discussed below) might offer more nuanced insights.

For our three portfolio examples, we'll consider only monthly returns over a 6-month period for each portfolio, as detailed in the table below:

As the table above illustrates, Portfolio C exhibits the highest volatility with a standard deviation of 2.5%, reflecting greater dispersion in its returns over the 6-month period. In contrast, Portfolios A and B, both with a standard deviation of 1.7%, demonstrate more consistent returns, indicating moderate volatility.

Historical Maximum Drawdowns

The historical maximum drawdown is a measure that shows the largest decrease in value an asset or portfolio has experienced over a specific period. It helps investors understand the past risks and potential losses during market downturns. By examining the historical maximum drawdown, investors can make better decisions about managing risks and building their portfolios.

The Max Drawdown formula is shown below:

Max Drawdown = (Py / Px) - 1

where:

  • Max Drawdown = Represents the magnitude of the largest loss
  • Px = Peak value of the investment or portfolio
  • Py = Trough value after the peak value

For investors who want to understand the worst-case scenarios their portfolios have faced, the historical maximum drawdown is a useful tool. It gives a clear picture of how assets have performed during challenging market conditions in the past. This information can guide investors in preparing for potential future downturns.

However, it's essential to remember that past performance doesn't guarantee future results. Just because an asset had a certain drawdown in the past doesn't mean it will face the same challenges in the future. Also, for assets with a short history or those that have undergone significant changes, the historical maximum drawdown might not provide a full risk assessment.

Below is a table detailing the components of the historical max drawdown for three distinct portfolios (assume a 12-month period):

As the table above suggests, Portfolio A has been more resilient in managing losses over time.

Value at Risk

The Value at Risk (VaR), is a statistical metric that quantifies the potential loss an investment or portfolio might face over a period of time, given a specific confidence level. Essentially, VaR gives investors a numerical value that represents the worst-case scenario for their investments, up to a certain probability.

For instance, a VaR of $100,000 at a 95% confidence level implies that there's a 5% chance the portfolio could more than $100,000 over the specified period. To elaborate, the 95% confidence level indicates that in 95 out of 100 cases (or 95% of the time), the losses will be $100,000 or less, while in the remaining 5 cases (or 5% of the time), the losses could exceed $100,000.

The VaR formula is shown below:

VaR = V - Vα

where:

  • VaR = Value at Risk
  • V = Current value of investment or portfolio
  • Vα = Potential loss at specified confidence level (α)

VaR is particularly useful for investors who want a clear, quantifiable measure of the downside risk associated with their investments. It offers a straightforward way to gauge potential losses, making it easier to align investment strategies with risk tolerance levels.

The limitations of VaR include its focus on potential losses up to a specified confidence level, without shedding light on potential losses beyond that threshold. Furthermore, VaR's reliance on historical data comes with the caveat that past performance doesn't necessarily predict future outcomes.

The table below illustrates the Value at Risk (VaR) at a 95% confidence level for three portfolios (assume a 12-month period):

As the table above shows, Portfolio B has the highest VaR at $7,500, indicating that there's a 5% chance that this portfolio could incur losses greater than $7,500 over the specified period. This suggests that Portfolio B carries a higher potential downside risk compared to the other two portfolios, making it a riskier investment choice in terms of potential losses.

Analyzing Risk-Adjusted Performance Metrics

Achieving returns is one aspect; understanding the risk taken to realize those returns is another. This section introduces the Sharpe Ratio, Sortino Ratio, and Treynor Ratio, three fundamental metrics that provide insights into the risk-adjusted performance of a portfolio.

Sharpe Ratio

The Sharpe Ratio offers investors a means to evaluate the risk-adjusted performance of a portfolio. At its core, the Sharpe Ratio measures the excess return an investment has generated for each unit of risk taken, relative to a risk-free investment. The formula for this metric is straightforward: it subtracts the risk-free rate (commonly represented by the yield on 3-month government bonds, which are seen as virtually guaranteed and highly liquid) from the portfolio's return, and then divides the result by the portfolio's standard deviation, a measure of its volatility.

The Sharpe Ratio formula is shown below:

Sharpe Ratio = (Rp - Rf) / σp

where:

  • Rp = portfolio's expected return
  • Rf = risk-free rate
  • σp = standard deviation of portfolio

For investors seeking to evaluate the effectiveness of their investments, the Sharpe Ratio serves as a valuable metric. A portfolio with a higher Sharpe Ratio indicates a history of yielding superior returns relative to its risk level. This becomes especially advantageous when contrasting various investments or portfolios since the Sharpe Ratio offers a consistent benchmark for risk-adjusted performance. The formula's numerator, (Rp - Rf), represents the portfolio's return over and above the risk-free rate, highlighting the potential benefits of assuming additional risk. On the other hand, the denominator provides a measure of the portfolio's volatility, shedding light on the unpredictability of its returns.

The limitations of the Sharpe Ratio include its reliance on historical data, which, while insightful, doesn't assure future results. Additionally, while the Sharpe Ratio measures a portfolio's total volatility, it doesn't differentiate between upward and downward fluctuations.

Below is a table detailing the components of the Sharpe Ratio for three distinct portfolios (assume a 12-month period):

As the table above illustrates, Portfolio A has the highest Sharpe Ratio, indicating that it has generated the highest excess return for each unit of risk taken. Portfolio C has the lowest Sharpe Ratio, suggesting it has a less favorable risk-adjusted return compared to the other two portfolios.

Sortino Ratio

The Sortino Ratio, akin to the Sharpe Ratio, serves as a tool for investors to evaluate the risk-adjusted return of a portfolio. However, while both ratios share the same numerator, which represents the excess return over the risk-free rate, they differ in their denominators. The Sharpe Ratio uses the standard deviation of the entire portfolio, capturing both upward and downward volatility. In contrast, the Sortino Ratio employs the downside deviation, which focuses solely on the standard deviation of negative returns. This distinction arises from the practical observation that investors are primarily concerned with negative returns, viewing them as "bad risk."

Downside deviation offers a more precise measure of potential losses, making the Sortino Ratio a preferred metric for some investors when assessing excess return per unit of undesirable risk. This specificity means the Sortino Ratio doesn't account for the portfolio's upside potential, which some might argue is a limitation.

The Sortino Ratio formula is shown below:

Sortino Ratio = (Rp - Rf) / σd

where:

  • Rp = portfolio's expected return
  • Rf = risk-free rate
  • σd = downside risk (standard deviation of negative returns)

Both the Sharpe and Sortino Ratios are most relevant when one deems standard deviation as a fitting measure of risk. This implies that a portfolio encompasses both idiosyncratic (company-specific) risks and market risks. Additionally, these ratios operate under the assumption that returns follow a normal distribution. If a portfolio's returns deviate significantly from this norm and one still relies on standard deviation, there's a risk of underestimating the portfolio's actual risk.

In summary, while the Sharpe Ratio provides a broad view of a portfolio's volatility, the Sortino Ratio narrows its focus to downside risk, making it especially valuable for those keen on understanding their exposure to potential losses.

Below is a table detailing the components of the Sortino Ratio for three distinct portfolios (assume a 12-month period):

The table above shows that Portfolio A has the highest Sortino Ratio, indicating the highest excess return per unit of bad risk. Portfolio C has the lowest Sortino Ratio, suggesting it has the least favorable risk-adjusted return when considering only the downside volatility.

Treynor Ratio

The Treynor Ratio is a metric designed to evaluate the risk-adjusted performance of an investment or portfolio, focusing specifically on systematic or market risk. Like the Sharpe and Sortino Ratios, the Treynor Ratio's numerator represents the excess return of a portfolio over the risk-free rate. However, its distinctiveness lies in the denominator, which uses the portfolio's beta. Beta gauges the sensitivity of a portfolio's returns relative to the broader stock market's movements, making it a direct measure of market risk.

The Treynor Ratio formula is shown below:

Treynor Ratio = (Rp - Rf) / β

where:

  • Rp = portfolio's expected return
  • Rf = risk-free rate
  • β = beta (systematic risk of portfolio)

While standard deviation encompasses both market risk and asset-specific (idiosyncratic) risk, beta solely captures market risk. It's worth noting that idiosyncratic risk pertains to individual company factors and can be mitigated through proper diversification. In contrast, market risk remains inherent and cannot be diversified away.

The Treynor Ratio becomes particularly relevant for portfolios where idiosyncratic risk has been effectively diversified out, leaving only market risk. If an investor is confident that their portfolio is well-diversified, eliminating company-specific risks, the Treynor Ratio offers a valuable perspective. However, its utility diminishes for portfolios that adopt a "market neutral" strategy, targeting a beta of zero. In such scenarios, the Treynor Ratio becomes inapplicable due to the division by zero. In essence, the Treynor Ratio offers insights into the returns generated per unit of market risk, making it a valuable tool for portfolios primarily exposed to systematic risks.

Below is a table detailing the components of the Treynor Ratio for three distinct portfolios (assume a 12-month period):

As the table above shows, Portfolio A has the highest Treynor Ratio, indicating that it generates the highest return per unit of market risk. Portfolio C has the lowest Treynor Ratio, suggesting it has a less favorable risk-adjusted return concerning systematic risk.

Measuring Market Sensitivity and Diversification

A portfolio's behavior in relation to the broader market can be indicative of its risk profile and diversification. Through metrics like Beta and R-Squared, this section offers insights into market sensitivity and the extent to which a portfolio's movements can be attributed to market-wide fluctuations.

Beta

Beta is a key metric used to evaluate a portfolio's responsiveness to market shifts, offering insights into how the returns of a portfolio might fluctuate relative to a chosen benchmark, commonly a market index such as the S&P 500.

The formula for beta is shown below:

Beta (β) = Cov(Rp, Rm) / Var(Rm)

where:

  • β = beta (systematic risk of portfolio)
  • Rp = Portfolio's return
  • Rm = Market's return
  • Cov(Rp, Rm) = Covariance between the portfolio's return and the market's return
  • Var(Rm) = Variance of the market's return

After finding beta, here's how it can be interpreted:

  • β > 1: Indicates higher sensitivity to market movements with potential for greater volatility.
  • β = 1: Portfolio is expected to move in sync with the market.
  • β < 1: Denotes lower market sensitivity, suggesting the portfolio might be less volatile than the market.

Understanding beta is crucial for investors as it highlights a portfolio's systematic risk and guides informed investment decisions aligned with risk tolerance. However, it's important to note that beta is most applicable when investors are assessing market risk and when the portfolio has a clear relationship with the benchmark. In cases where a portfolio is designed to be market-neutral or when it does not closely follow the market index, the utility of beta may be limited, and alternative risk assessment tools might be more suitable.

Below is a table detailing the components of Beta for three distinct portfolios (assume a 12-month period):

As the table above illustrates, Portfolio A has the highest beta, indicating the highest sensitivity to market fluctuations. Portfolio B has a beta of 0, suggesting it is not influenced by market movements. Portfolio C has a negative beta, indicating it moves in the opposite direction of the market. Note that the variance of the market return (Var(Rm)) remains constant for all portfolios because it's solely based on the market's performance, which is the same for each portfolio in this scenario.

R-Squared

R-Squared provides insight into the correlation between a portfolio's movements and those of a benchmark index. It is quantified as a percentage, ranging from 0 to 100.

The formula for R-Squared is shown below:

R-Squared (R²) = [Cov(Rp, Rm)²] / [Var(Rp) * Var(Rm)]

where:

  • R² = R-Squared
  • Rp = Portfolio's return
  • Rm = Market's return
  • Cov(Rp, Rm) = Covariance between the portfolio's return and the market's return
  • Var(Rp) = Variance of the portfolio's return
  • Var(Rm) = Variance of the market's return

An R-Squared value nearing 100 signifies that most of the portfolio's variations are influenced by market-wide factors represented by the benchmark. However, a high R-Squared doesn't guarantee future performance, and its value can be misleading if based on an inappropriate benchmark. Conversely, a low R-Squared indicates that the portfolio's performance is largely dictated by factors specific to individual stocks or sectors, rather than broad market trends.

For investors, R-Squared offers insight into portfolio diversification, highlighting the balance between market-driven performance and specific investment choices. However, as with other metrics discussed in this article, it's crucial not to lean entirely on R-Squared, as it might not fully encompass all risks or the intricacies of a portfolio's behavior.

Below is a table detailing the components of R-Squared for three distinct portfolios (assume a 12-month period):

As evident in the table above, Portfolio A and C exhibit notably high R-Squared values, signifying that a substantial portion of their fluctuations can be attributed to market factors. Conversely, Portfolio B stands out with an R-Squared value of 0, implying that its performance remains largely independent of market dynamics.

The Bottom Line

Understanding how to measure your portfolio's risk-adjusted performance is crucial for long-term investing success. Assessing portfolio risk involves delving into metrics like Value at Risk (VaR) to anticipate potential losses, analyzing Historical Max Drawdowns to gauge past vulnerabilities, and using Standard Deviation to capture return fluctuations. On the performance front, the Information Ratio offers insights into the returns of a portfolio relative to a benchmark, while Alpha provides a lens into the excess returns generated. Beyond these, risk-adjusted performance metrics such as the Sharpe, Sortino, and Treynor Ratios are pivotal in understanding the returns achieved relative to the risks undertaken. Metrics like Beta and R-Squared further illuminate a portfolio’s market sensitivity and diversification level.

It's important to emphasize that a comprehensive understanding of a portfolio's real risk-adjusted performance should involve a holistic assessment of all these metrics in tandem. Relying on a single metric may provide an incomplete picture. Fortunately, these metrics can be readily calculated using tools like Excel. For example, in this article where I discuss the Capital Asset Pricing Model (CAPM), I provide step-by-step instructions on how to calculate the risk-free rate, beta, expected returns of the market, standard deviation, r-squared, and excess returns (alpha) in Excel.

In conclusion, a thorough investment analysis extends beyond mere return metrics. By integrating both risk and performance indicators, investors can strategically balance anticipated gains with inherent risks, ensuring a sound and informed investment strategy.

Disclaimer: Because the information presented here is based on my own personal opinion, knowledge, and experience, it should not be considered professional finance, investment, or tax advice. The ideas and strategies that I provide should never be used without first assessing your own personal/financial situation, or without consulting a financial and/or tax professional.

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