Beta equation

Beta Equation Security
Beta Equation Security definition :
The market beta of a security is determined as follows: Regress excess returns of stock y on excess returns of the market. The slope coefficient is beta.

Beta equation (Mutual Funds)
The beta of a fund is determined as follows:
[(n) (sum of (xy)) ]-[ (sum of x) (sum of y)]
[(n) (sum of (xx)) ]-[ (sum of x) (sum of x)]
where: n = # of observations (36 months) ...

Beta equation (security)
The market beta of a security is determined as follows: Regress excess returns of stock y on excess returns of the market. The slope coefficient is beta. Define n as number of observation numbers.
Beta= ...

Beta equation
The beta of a security is determined as follows:
[(n) (sum of (xy)) ]-[ (sum of x) (sum of y)]
[(n) (sum of (xx)) ]-[ (sum of x) (sum of x)] ...

not necessarily a complete measure of risk (you may need multiple betas). Also, note that the beta is a measure of comovement, not volatility. It is possible for a security to have a zero beta and higher volatility than the market.
Beta equation ...

[CFTC] beta equation The beta of a stock is determined as follows: [(n) (sum of (xy)) ]-[(sum of x) (sum of y)] / [(n) (sum of (xx)) ]-[(sum of x) (sum of x)]; where: n = # of observations (24-60 months), x = rate of return for the S&P 500 Index, ...

See also: Observation, Expense, Bills, Systematic risk, Convertible Bond