问题如下：
What is the relationship between CAPM and the market model?
解释：
These models are frequently confused because they both demonstrate a relationship between every asset and the market portfolio.The market model is an empirical model based on realized rates of return, whereas CAPM is based on expected and unobserved variables. It also provides a method of decomposing asset returns into two components: a systematic (or market) component and a residual (or non-market) component:
rp = ap + bprM + εp
where rp = Rp - r is the excess return of the portfolio return Rp over the risk-free rate r and rM = RM - r is the excess return of the market portfolio RM over the riskfree rate r.
The residual component ep is uncorrelated with the market excess return rM. The systematic component is beta multiplied by the market excess return. The market model thus appears to be a natural framework for estimating beta.CAPM is an equilibrium pricing model, which suggests that each asset is priced so that its expected return compensates for its contribution to the market portfolio risk. The asset's expected return is thus found to be proportional to its beta. For a well-diversified portfolio, an asset's risk contribution will approximate its risk contribution to the market portfolio.
老师好，这个知识点在讲义上没找到，只需要了解即可吧？