Jensen's Alpha
Also called: Jensen alpha, Jensens alpha, CAPM alpha
Jensen's alpha is the return a portfolio earned beyond what CAPM says its beta deserved. It was the first rigorous attempt to separate skill from leverage, and the answer for most funds was uncomfortable: alpha near zero before fees and negative after. Its weakness is model dependence — much of what looked like alpha in single-factor tests turned out to be exposure to size, value and momentum once multi-factor models arrived.
Formula
α = Portfolio return − [Risk-free + β × (Market return − Risk-free)]
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