FINS2624 Chapter Notes - Chapter 9-12: Risk-Free Interest Rate, Capital Asset Pricing Model, Risk Premium
Chapter 9
- The CAPM assumes that investors are single-period planners who agree on a common input
list from security analysis and seek mean-variance optimal portfolios
- The CAPM assumes that security markets are ideal in the sense that: they are large and
investors are price takers, there are no taxes or transaction costs, all risky assets are publicly
traded, investors can borrow and lend any amount at a fixed risk free rate
- With these assumptions all investors hold identical risky portfolios. The CAPM holds that in
equilibrium the market portfolio is the unique mean-variance efficient tangency portfolio.
Thus a passive strategy is efficient
- The CAPM market portfolio is a value weighted portfolio. Each security is held in a proportion
equal to its market value divided by total MV of all securities
- If the market portfolio is efficient and the average investor either borrows nor lends, then the
risk premium on the market portfolio is proportional to its variance and to the average
coefficient of risk aversion across investors
- The CAPM implies that the risk premium on any individual asset or portfolio is the product of
the risk premium on the market portfolio and the beta coefficient, where it is equal to the
covariance of the asset with the market portfolio as a fraction of the variance of the market
portfolio
- When risk-free investments are restricted but all other CAPM assumptions hold, then the
simple version of the CAPM is replaced by its zero-eta potfolios epeted ate of etu
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Document Summary
The capm assumes that investors are single-period planners who agree on a common input list from security analysis and seek mean-variance optimal portfolios. With these assumptions all investors hold identical risky portfolios. The capm holds that in equilibrium the market portfolio is the unique mean-variance efficient tangency portfolio. The capm market portfolio is a value weighted portfolio. Each security is held in a proportion equal to its market value divided by total mv of all securities. If the market portfolio is efficient and the average investor either borrows nor lends, then the risk premium on the market portfolio is proportional to its variance and to the average coefficient of risk aversion across investors. When risk-free investments are restricted but all other capm assumptions hold, then the simple version of the capm is replaced by its zero-(cid:271)eta po(cid:396)tfolio(cid:859)s e(cid:454)pe(cid:272)ted (cid:396)ate of (cid:396)etu(cid:396)(cid:374)