Alpha is an important concept for investors to understand when evaluating investment returns and manager performance. In essence, alpha measures how much extra return an investment generates compared to its benchmark.

Grasping the difference between alpha and beta as return drivers enables smarter assessment of asset managers and your portfolio’s risk-adjusted returns. This guide provides a deep dive into the definition, interpretation, and limitations of using alpha in investment analysis.

Definition of Alpha

Alpha measures the excess return of an investment relative to its expected performance based on its risk level.

  • Positive alpha means the investment outperformed its risk-adjusted return expectation.
  • Negative alpha indicates the investment lagged its expected return given its beta risk profile.
  • Alpha of zero means the investment met expectations exactly without exceeding or missing them.

In short, higher alpha is better as it shows the manager generated excess returns beyond general market moves or benchmarks.

Alpha Versus Beta

Beta measures an investment’s volatility correlation with the overall market’s ups and downs. S&P 500 index funds have a beta of 1.0 – they move in sync with the market.

Alpha is return beyond what would be expected given the investment’s beta. For example:

  • S&P 500 returns 10% for the year. A fund with beta of 1.0 should also return about 10%.
  • If the fund instead returns 15%, its alpha is 5% – the amount it outperformed its beta expectation.

Positive alpha means the investment did better than predicted based on its relative riskiness.

How to Calculate Alpha

Alpha is determined by comparing actual returns to a relevant benchmark, usually over a 5-10 year period. The basic formula is:

Alpha = Investment Return – Benchmark Return

For example, if a fund returned 9% over 5 years when its benchmark returned 7% over the same period, the fund’s alpha would be:

Alpha = 9% Return – 7% Benchmark Return Alpha = 2%

So this fund outpaced its benchmark by 2% annually, indicating positive alpha generation.

Assessing Investment Manager Alpha

Alpha is commonly used to evaluate active investment managers. Comparing a manager’s returns to an appropriate index benchmark reveals if they consistently add value and skill on a risk-adjusted basis.

Higher alpha signals the manager’s security selection abilities and strategic decisions are paying off. This justifies the higher fees charged by actively managed funds versus passive index funds.

But beware of false or misleading alpha. Some managers take excessive risk to chase extra returns, giving the illusion of alpha. Also note alpha tends to mean revert over longer periods. Truly skillful alpha endures across full market cycles.

Alpha Limitations and Misuse

While a widely used metric, alpha has some limitations to consider:

  • Alpha depends heavily on benchmark choice. Different benchmarks can lead to drastically different alpha readings for the same performance.
  • Unmanaged factors like sector biases can affect alpha calculations, giving misleading results about manager skill.
  • Alpha doesn’t quantify potential risks taken to achieve excess returns.
  • Short-term alpha runs may be random rather than skill-based. Multi-year analysis gives more reliable alpha insights.
  • Fees are not incorporated into alpha, but obviously impact net realized returns.

So while a useful starting point, alpha requires deeper examination to assess investment manager efficacy and skill. Don’t rely solely on alpha figures when making decisions.

Frequently Asked Questions About Investing Alpha

Can individual investors generate alpha?

Yes, but it requires extensive research and knowledge. Most excess returns from individuals come from assuming more risk, not true skill.

What is a good alpha figure to target or expect?

Aim for 0.5% to 2% alpha annually for skilled active managers. Higher claims require skeptical examination for validity.

What types of funds and strategies tend to produce the highest alpha?

Less efficient market areas like small caps, high yield bonds, and emerging markets offer more alpha opportunities.

Do index funds generate alpha?

By definition no, index funds do not seek to create alpha. But smart strategic tilts toward certain factors like value or momentum can earn excess returns.

Is negative alpha always a sign of poor investments?

Not necessarily. Negative alpha could result from low-risk bonds or a diversified portfolio in a high-return environment.

Can an investment have positive alpha but negative absolute returns?

Yes, if the benchmark itself has even larger negative returns in a down market.

Is alpha useful for measuring individual stock returns?

Less so since single stocks are inherently riskier. Alpha has more validity in assessing entire portfolios and funds.

While alpha has some flaws, it remains one of the best single metrics for succinctly gauging investment skill and excess returns. Used appropriately, alpha offers quick insights into portfolio performance.


  • Gio Watts

    Gio Watts brings over 10 years of digital marketing experience to his role as marketing manager at Walletminded. In his current position, Gio oversees brand marketing, campaign management, and audience growth initiatives. Prior to joining Walletminded, Gio held marketing roles at several ecommerce and SaaS startups, most recently serving as senior marketing manager at CloudTable Inc. There, he specialized in paid social advertising and content marketing. Gio holds a bachelor’s degree in business marketing from the University of Oregon. He is a certified content marketing specialist and frequently guest lectures at his alma mater. When he's not devising omni-channel marketing campaigns, you can find Gio coaching youth basketball and indulging his passion for live music.

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