Active return is one of the most important measurements investors should make with their portfolios. And a full understanding of active return can provide powerful insights into how your investments are performing.
Many investors often compare their portfolio’s performance to a benchmark. Like, an index or composite that represents the market or strategy they’re making. At first glance, it may seem like evaluating “active return” is straightforward:
Active Return = Portfolio Return − Benchmark Return
While this formula is directionally correct, it oversimplifies what’s really happening beneath the surface. There is more to measuring active return than a simple equation. Active return is not only shaped by security selection, but also by asset allocation, and the characteristics of the benchmark itself.
Plus, simply subtracting returns can mislead investors about where outperformance or underperformance truly comes from.
This post explains what active returns really represent, why they aren’t as simple as subtracting one number from another, and how concepts like alpha, beta, and benchmarking help us evaluate the true drivers of investment performance.
What Active Returns Really Represent
Active returns measure the value added above a benchmark, but the “active” portion can come from several places.
The most straight-forward source is security selection, often referred to as alpha, which reflects whether the chosen investments perform differently than the benchmark’s holdings. Measuring the active return of a US stock portfolio against the S&P 500 means measuring security selection effect. The result of choosing stocks, and this performance, relative to the benchmark (S&P 500).
Its worth pointing out that most active investment managers underperform their benchmarks. This happens for a variety of reasons including emotional bias. But it also occurs because most active managers hold at least some portion of their portfolios in cash. Which the S&P 500 never does. So, since stocks outperform cash most periods, active managers will naturally underperform passive benchmarks.
So, measuring active return of a single asset class is straightforward. But things get a little less intuitive when measuring the active return of an entire portfolio.
When it comes to the active return of an entire portfolio, a more important source of active return is asset allocation. In other words, how much weight a portfolio places in stocks, bonds, or other asset classes compared to the benchmark allocation. A portfolio that holds 70% stocks while its benchmark holds 60% will naturally behave differently, even if it owns similar securities.
So, when we review the active return on an entire portfolio, it’s not a simple case of subtracting portfolio returns from the benchmark return. The amount of asset class allocation relative to the benchmark portfolio also matters. Plus, the rebalancing period and the aggregation period of the benchmark will also impact the results.
Why Active Returns Aren’t Just Simple Subtraction
This is why active returns are not as straightforward as subtracting one number from another when measuring an entire portfolio. Asset allocation matters to portfolio returns, in addition to security selection.
This is also why investors should dig deeper into why an active return occurred. Consider the volatility, concentration, sector allocation, and style preferences made by the portfolio. Including asset class allocation. The portfolio may have benefited from geographic tilts, style preferences, currency differences, or usually, holding a bit of cash when the benchmark was fully invested. Without breaking these effects apart, investors can’t tell whether a result reflects skill, risk-taking, or luck.
Why Allocation Matters—even Within a Single Asset Class
A global equity manager compared to a U.S.-only index will produce active returns simply because of geographic differences. A value-tilted manager will diverge from a broad-market benchmark due to style exposure. And if a portfolio has a higher beta—a higher sensitivity to market movements—it will outperform in rising markets and underperform in declining ones, regardless of security selection skill. All these differences show up as active returns.
Understanding Alpha and Beta
This is where concepts like alpha and beta provide clarity.
Beta captures how much of a portfolio’s movement comes from general market exposure. A higher beta amplifies both gains and losses and is not considered evidence of skill.
- A beta > 1 amplifies both gains and losses.
- A beta < 1 reduces both gains and losses.
Alpha represents the portion of return not explained by beta or allocation differences; it reflects value added through security selection or unique insights. Alpha is what investors typically want from active managers—evidence that they can outperform due to genuine insight. If a portfolio beats its benchmark but carries extra market exposure, much of that outperformance may simply be due to taking on more risk rather than generating true alpha.
The Importance of Proper Benchmarking
Because of this, benchmarking is more than just a simple comparison. It should provide the context that defines what “active” really means.
A good benchmark should be:
- Representative of the manager’s investable universe
- Transparent in its construction
- Unambiguous (weights and constituents are clear)
- Investable (you could theoretically replicate it)
A good benchmark should reflect the portfolio’s investable universe and risk characteristics. When the benchmark is mismatched—such as using a U.S. index for a global manager or a broad market index for a style-specific strategy—active returns become less relevant.
Pulling It All Together
Ultimately, active return is a diagnostic tool. It helps investors understand what decisions were made, how those decisions contributed to performance, and whether the results are likely to be repeatable. By viewing active return through the lens of allocation, selection, alpha, beta, and proper benchmarking, investors can more accurately evaluate performance and make better portfolio decisions.
Our family office provides bespoke consolidated performance reporting to wealthy investors. The benefits of our reporting services go far beyond simply measuring returns and provide actionable insights that investors can use to improve their portfolio performance. To learn more about our services, e-mail me at james@markdalemanagement.com
