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o CAPM directly connects risk (beta) with expected return.
o Higher risk → higher expected return.
2. Beta as a Key Measure
o Beta shows how sensitive a stock is to market movements.
o Example: A beta of 1.5 means the stock is 50% more volatile than the market.
3. Market-Oriented
o CAPM assumes investors compare every asset to the overall market portfolio.
4. Simplicity
o Provides a straightforward formula for calculating expected returns.
5. Cost of Equity Estimation
o CAPM is widely used by companies to estimate the cost of equity when
making investment decisions.
6. Focus on Systematic Risk
o CAPM only considers systematic risk (market-wide risk), not unsystematic risk
(company-specific risk).
Assumptions of CAPM
CAPM is built on several assumptions, which make it elegant but also unrealistic:
1. Investors are Rational and Risk-Averse
o Assumes all investors make logical decisions and prefer less risk.
2. Perfect Capital Market
o No transaction costs, taxes, or restrictions.
3. Homogeneous Expectations
o All investors have the same expectations about returns, risks, and future
performance.
4. Risk-Free Borrowing and Lending
o Investors can borrow or lend unlimited money at the risk-free rate.
5. Single Period Investment Horizon
o Assumes investors plan for only one period (like one year).
6. Market Portfolio is Efficient
o Assumes all investors hold a mix of assets that perfectly represents the
market.
7. Only Systematic Risk Matters
o Company-specific risks can be diversified away, so only market risk affects
returns.
Criticisms of CAPM
While CAPM is elegant, it faces criticism:
• Unrealistic Assumptions: Real markets have taxes, transaction costs, and irrational
investors.
• Beta Limitations: Beta may not fully capture risk; past volatility doesn’t always
predict future risk.