Jensen's Alpha — What Is Alpha in Investing?

Definition

Alpha (α), also known as Jensen's alpha, is a measure of excess investment return beyond what the CAPM (Capital Asset Pricing Model) predicts for a given risk level (beta).

Simply put: alpha tells you how much more (or less) you earned than you should have, considering the risk you took.

Interpretation

• α > 0 — portfolio beat the benchmark after adjusting for risk (manager added value)
• α = 0 — portfolio performed exactly as the model predicted
• α < 0 — portfolio lost to the benchmark (manager subtracted value)

Formula

α = Rp - [Rf + β × (Rm - Rf)]

Where:

• Rp = actual portfolio return
• Rf = risk-free rate
• β = portfolio beta
• Rm = market return (benchmark)

Example

Your portfolio earned 15%, the market (S&P 500) 12%, risk-free rate 3%, portfolio beta 1.2.

α = 15% - [3% + 1.2 × (12% - 3%)]
α = 15% - [3% + 10.8%]
α = 15% - 13.8% = +1.2%

Your alpha is +1.2% — you earned 1.2% more than the model predicted for your risk level.

Why is alpha important?

Alpha is a key metric for evaluating:

• Fund managers — is the active fund worth higher fees?
• Your portfolio — do your decisions add value vs simple index ETF?

Studies show that 80–90% of active funds generate negative alpha after fees. That's why many experts recommend passive investing (ETFs).

Alpha vs beta

• Beta = how much market risk you're taking
• Alpha = how much additional return you're generating beyond that risk

Passive investors aim for beta = 1 and alpha = 0 (same results as the market). Active investors seek positive alpha.

How Freenance can help?

Freenance can calculate your portfolio's alpha by comparing results to a selected benchmark. Check if your investment decisions truly add value — or whether it's better to switch to a simpler ETF portfolio.

👉 Measure your portfolio's alpha with Freenance — freenance.io

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