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The General Use of Predictive Models. Weather Sports Accuracy?. Efficient Portfolios. To find the Optimal risky Portfolio we have used: Mean return Variance Standard Deviation Covariance Correlation The benefits of diversification. Pricing Models for Individual Securities.
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The General Use of Predictive Models • Weather • Sports • Accuracy? Intermediate Investments F303
Efficient Portfolios • To find the Optimal risky Portfolio we have used: • Mean return • Variance • Standard Deviation • Covariance • Correlation • The benefits of diversification Intermediate Investments F303
Pricing Models for Individual Securities • Defining terms • CAPM: a model that provides a precise prediction of the relationship we should observe between the risk of an asset and its expected return • Arbitrage: The exploitation of security mis-pricing to earn risk free economic profits • Equilibrium Pricing: pricing situation under which there are no opportunities for Arbitrage • Beta: The sensitivity of a security’s return to systematic risk Intermediate Investments F303
CAPM and CAL, CML & SML • Capital Allocation Line (CAL) • Capital Market Line (CML) • Security Market Line (SML) • CAPM expected return-beta relationship = E(ra) = rf + Betaa [ E(rm) – rf] • Purpose of CAPM Intermediate Investments F303
Underlying Assumptions for CAPM (p. 233) • Investors cannot affect prices by their own individual trades • All investors have the same holding periods • All investments are publicly traded and investors can borrow or lend at the risk free rate • There are no taxes or transaction costs • All investors will select the optima portfolio (market portfolio) • All investors have the same expectations about the variables affecting securities Intermediate Investments F303
What does this imply for a market in equilibrium? • All investors will choose to hold the market portfolio • The market portfolio will fall on the efficient frontier and be the optimal risky portfolio • The risk premium on M will be proportional to the variance of the market portfolio and the investors’ typical degree of risk aversion E(rm) – rf = A*Varm Note: The greater the value of A* the more risk averse the investor Intermediate Investments F303
What does this imply for a market in equilibrium? • The risk premium on individual assets will be proportional to the risk premium on the market portfolio, M, and to the beta coefficient of the security on the market portfolio. So, the rate rate of return on a single asset is determined by the rate of return on the Market and the security’s beta. Intermediate Investments F303
Beta • Beta is the regression coefficient obtained from regressing a security’s return against the returns of the market portfolio Beta = Cov (Ri , Rm) / Varm Intermediate Investments F303