Business A to Z

Beta Equation (Stocks)


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
y = rate of return for the stock


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