Alpha Decay
Alpha Decay — Speed at which a signal loses predictive power as capital competes for it.
Definition
Alpha Decay refers to speed at which a signal loses predictive power as capital competes for it. Keep that definition fixed when comparing series, managers, or regimes — renaming the same tape does not create a new signal.
Why it matters
It is an operating object: if the definition drifts, routing, risk limits, and audit trails drift with it. When speed at which a signal loses predictive power as capital competes for it shifts, related hedges, limits, and narratives usually need an explicit update rather than a quiet assumption.
Case
Suppose a desk is positioned for the opposite of what alpha decay is saying. If speed at which a signal loses predictive power as capital competes for it moves against that book, the first question is not “is the story clever?” but whether size, hedges, and stop logic still match the observation.
How to read it
Verify ownership, inputs, and failure alerts the same way you would for a production control. Prefer a short written null hypothesis for Alpha Decay: what would falsify the current reading in the next window?