© 2012 McGraw-Hill Ryerson LimitedChapter The Market Portfolio ◦ Portfolio of all assets in the economy. In practice a broad stock market index, such as the S&P TSX or S&P 500 Composite Index, is used to represent the market. ◦ The market portfolio is used as a benchmark to measure the risk of individual stocks Beta ◦ Sensitivity of a stock’s return to the return on the market portfolio ◦ Beta (denoted ) is a measure of market risk LO1, LO2
© 2012 McGraw-Hill Ryerson LimitedChapter Measuring beta: Example: Turbot Charged Seafood has the following returns on its stock, relative to the listed changes in the return on the market portfolio. The first three months, every time that the market return was 1% the return for Turbot were 0.8%, 1.8% and -0.2% respectively. In the next three months, every month the market return was -1% and the Turbot returns were -1.8%, 0.2% and -0.8% respectively. Beta of Stock j = j = % change in return of Stock j % change in return of the market LO1, LO2
© 2012 McGraw-Hill Ryerson LimitedChapter MonthMarket Return %Turbot Return % Average = +0.8% Average = -0.8% 1.6% LO1, LO2
© 2012 McGraw-Hill Ryerson LimitedChapter Market Return (%) Stock Return (%) Calculating Beta = slope of line = Calculating Beta for Turbot LO1, LO2
© 2012 McGraw-Hill Ryerson LimitedChapter There are two ways of measuring beta: Beta of Stock j = j = cov(r j, r m ) mm 2 Where: Cov (j,m) = covariance of the stock’s return with the market’s return m = standard deviation of the market LO1, LO2
© 2012 McGraw-Hill Ryerson LimitedChapter The other way… Where: jm = correlation of the stock’s return with market’s return j = standard deviation of the stock m = standard deviation of the market Beta of Stock j = j = jm j mm LO1, LO2
© 2012 McGraw-Hill Ryerson LimitedChapter Example: Correlation of the stock’s return with the market’s return ( jm ) = 0.70 Covariance of the stock’s return with the market’s return (cov jm ) = 420 Standard deviation of the market ( m ) = 20% Standard deviation of the stock ( j ) = 30% j = 0.7(30) 20 = = 1.05 LO1, LO2
© 2012 McGraw-Hill Ryerson LimitedChapter LO1
© 2012 McGraw-Hill Ryerson LimitedChapter Portfolio Beta: the weighted average of the betas of the individual assets; with the weights being equal to the proportion of wealth invested in each asset The beta of a portfolio of two assets: Portfolio Beta = ( fraction of portfolio x beta of in 1 st asset 1 st asset ) + ( fraction of portfolio x beta of in 2 nd asset 2 nd asset ) LO1
© 2012 McGraw-Hill Ryerson LimitedChapter Example: You have a portfolio with 50% of your money invested in Cameco and 50% in Royal Bank stock The beta for Cameco is 1.51 while Royal Bank beta is 0.63 Portfolio beta = [0.5 1.51] + [0.5 0.63] = 1.07 LO1