The Meaning of Excess Return (Alpha)
A fund boasts that it 'made 15% this year.' But if the whole market rose 20%, this fund actually lagged the market. Excess return looks at exactly this 'versus a benchmark' performance.
What is excess return
Excess Return is your investment return minus the return of a 'comparison standard (benchmark).' If the benchmark is the S&P 500 and your return is 15% while the S&P 500 rose 20%, the excess return is −5%. You didn't beat the market—you lost to it.
Excess return is sometimes defined 'versus the risk-free rate.' Depending on the context, you need to check whether the standard is a benchmark index or a safe deposit rate.
Alpha — a metric of management skill
Alpha means the 'excess return that beat the benchmark even after accounting for risk.' It looks not simply at whether you made more, but whether you did better relative to the risk taken.
Strictly, like Jensen's alpha, it's calculated as the difference between the return predicted by the CAPM model (the expected return commensurate with the risk) and the actual return. A positive (+) alpha means you produced excess performance through skill relative to risk, and a negative (−) alpha means you merely took on more risk without producing performance.
'High return' and 'having alpha' are different. If you generated a return by taking on large risk, there may be no alpha.
Points to watch when looking at excess return
Excess return depends heavily on 'which benchmark you compared against.' Some deliberately pick an easy standard to inflate their skill, so you should first scrutinize whether the benchmark is appropriate.
Also, short-period excess return may be luck. To gauge true skill, you need to see whether excess return appears steadily over several years, and whether it remains after subtracting costs. In reality, active management that steadily beats the market (benchmark) over the long term is rare.
常见问题
Q. Are excess return and alpha the same thing?
They're similar but not exactly the same. Excess return is simply 'my return − the benchmark return.' Alpha goes further to account for risk (beta, etc.) and isolates only 'the excess that isn't explained by the risk taken.' Alpha is the stricter concept.
Q. Do index funds have an alpha of 0?
In theory, an index fund tries to track the market (benchmark) exactly, so it doesn't aim for alpha. In practice, because of management fees and tracking error, it often produces a slightly lower—that is, marginally negative (−)—excess return versus the benchmark.
📋 结果基于历史数据计算,过去的收益不代表未来的收益。
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