What it means
Alpha is the portion of a portfolio's return that cannot be explained by exposure to a benchmark or to standard risk factors. It's the part attributed to skill - what an active manager actually adds beyond what you could get cheaply through an index.
Why it matters
Alpha is the central claim of active management: that paying higher fees produces returns the index can't. Most active managers don't generate alpha after fees, which is why passive investing has eaten ~50% of the U.S. equity market.
How to use it
Compare a portfolio's annual return to a relevant benchmark (e.g., S&P 500 for U.S. large caps), then adjust for beta. If the residual is consistently positive across multiple periods, that's a signal - but watch for survivorship bias and short windows.
A fund returning 12% in a year the S&P returned 10%, with a beta of 1, generated ~2% of alpha.
Want a worked example or a deeper dive? Ask Rocky how this concept applies to your specific watchlist or trade idea.
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