Beta & Market Model
How much of a listing's movement its exchange benchmark explains — and how much it does not.
On any given day a listing moves partly because the whole market moved and partly because something happened to the company. This page regresses the listing's daily returns on its exchange benchmark's and splits the two apart: beta is how hard it responded to the market, R² is how much of its movement the market accounts for, and what is left over is the company's own.
- Reading a move correctly. A 3% fall on a day the index fell 2% is a very different event at beta 1.5 than at beta 0.4.
- Judging "outperformance". A high-beta listing beats the index in every rising market without doing anything clever.
- Knowing what diversification can reach. The idiosyncratic share is the risk that holding more names on the same exchange did not remove.
- Deciding whether index-level news matters. At a low R², the index tells you very little about this listing.
It is the return you could have earned over the same period without taking market risk — in practice the yield on a short government bill in the listing's own currency (India: the 91-day T-bill, in recent years around 6–7%; the US 3-month Treasury bill is the equivalent).
The model asks because it compares excess returns: the listing's return above that rate against the benchmark's return above it. Both sides get the same subtraction, so beta and R² barely move — it shifts alpha, by roughly (1 − beta) × the rate. Choosing it is really a choice about how to read alpha.
Leave it at 0% to read alpha as plain performance against the benchmark with no financing assumption. This app does not fetch a live bill yield — the number is yours, and the result states back which one was used.
Alpha here is what the benchmark did not account for over the window measured. It is a description of the past, never an expected return, a target, or a recommendation.