Investment Fundamentals Flashcards
CAPM assumptions
▶ investors are risk averse
▶ investors care only about mean and standard deviation or security returns are normally distributed
▶ NEW: investors have the same estimates of expected returns, volatilities and correlations (“homogeneous expectations”)
▶ NEW: investors can borrow/lend at the same riskfree rate
Security Market Line (SML)
- plot of the linear relationship between expected return and beta given by the CAPM
- SML is plotted in beta/return space ▶ as opposed to being plotted in standard deviation/return space (as in the CML)
the size effect
While small stocks do tend to have high beta, their returns are still high even after accounting for their higher beta
Regressions with a size factor (here Fama French’s SMB factor) as a second explanatory variable to beta - formula:
ri − rf = ai + bi * (rm − rf ) + si * rSMB + εi
Sort stocks on book-to-market (B/M):
High B/M → value stocks
Low B/M → growth stocks
value-minus-growth effect:
- Value stocks tend to have positive alphas
- growth stocks tend to have low or negative alpha
Fama-French 3-Factor Model:
- E (ri) = rf + bi * (E (rm) − rf ) + si * E (rSMB) + hi * E (rHML)
- rSMB - is the return on the ’size’ factor (return on a small cap portfolio minus return on a large cap portfolio)
- rHML - is the return on a ’value-minus-growth’ factor (return on high B/M portfolio minus return on a low B/M portfolio
- Also often written: E (ri) = rf + bi * E(MKT RF) + si * E(SMB) + hi * E(HML)
Empirical tests of the CAPM are difficult - CAPM could ’fail’ because:
▶ Behavioral biases
▶ No relation between return and marginal risk
▶ Frictionless market assumption in CAPM invalid: Non-tradable risks?
CAPM vs Multifactor Models
- CAPM: Expected returns are a function of covariance with the market portfolio
- Multifactor Models: ▶ Expected returns are a function of covariance with one or more “risk factors”. ▶ Assume that we have identified portfolios that we can combine to form an efficient portfolio; we call these portfolios factor portfolios
a one factor model
Typical factor portfolios:
Examples: Market Factor, Value Factor, Size Factor, Momentum Factor, High dividend, Quality, Volatility, …
Taking a factor/index model approach greatly simplifies the estimation of inputs, specifically covariances, into portfolio construction. The covariance between two stocks 𝑖 and 𝑗 can be simplified using their betas and the market variance - formula:
The covariance is then: σ2i,j = bi * bj * σ2m
Factor Models and Asset Allocation - we can simplify the variances/covariances of stocks for factor models, particularly index models, when estimating the inputs required for portfolio construction - moreover, firm-specific risks are uncorrelated across individual securities. For K risk factors we have:
Efficient Market Hypothesis – 3 versions
- Weak-form EMH: Stock prices already reflect all information contained in history of trading
- Semistrong-form EMH: Stock prices already reflect all public information
- Strong-form EMH: Stock prices already reflect all relevant information, including inside information
Post–earnings-announcement drift (PEAD)
tendency for stock prices to drift in the direction of an earnings surprise for several weeks following an earnings announcement
CAPM - how to calculate the beta
βi = σi,m/σ2m = ρi,m * σi/σm
CAPM – insights
- Developed by William Sharpe (published 1964, Nobel 1990) et al.
- In equilibrium, the tangency portfolio is the market portfolio
- (1) Leads to a relationship between the expected return on a security and its risk as measured by its beta
- (2) beta is the systematic risk of the security
The tangent portfolio is the market
portfolio - conditions
- Same beliefs ⇒ agree on tangency portfolio (PT )
- Everybody holds risky assets in same proportions ▶ Because risky holdings are proportional to the tangency portfolio (from two-fund separation) ▶ I hold 20% risk-free bond, 80% tangency port ▶ You hold -30% risk-free bond, 130% tangency port
- Thus, sum of everybody’s holdings has these properties: ▶ Proportional to tangent portfolio (by two-fund sep.) ▶ Equals the market portfolio (by definition).
The Capital Market Line (CML)
simply the CAL that combines investments in the riskfree asset and the market portfolio: E[ri] = rf + (E[m] − rf) / σm * σi
Contribution to excess expected return of market portfolio by individual stock - formula:
wi(E[ri] − rf )
Contribution to RISK of market portfolio by individual stock - formula:
- Not volatility (standard deviation), as firm-specific risk is diversified away, only market risk is priced
- Instead, the appropriate measure will be a function of how much that security contributes to the risk of the market portfolio, which in turn depends on the covariance of the security’s returns with the market portfolio
contribution to excess expected return of market portfolio for security i:
(E [ri] − rf) / σim –> In equilibrium this has to be the same for all securities (otherwise you can imporove the risk-return properties of the market portfolio) and it has to equal the ratio for the market as a whole:
What is beta in the CAPM equal to
βi = σi,m / σ2m = ρi,m * σi/σm
Capital Market Line (CML) - formula
rp = rf + σp * (rmkt − rf)/σmkt
What is the relation between β and standard deviation for efficient portfolios? Does this relation hold for inefficient portfolios?
- The relation between β and standard deviation for efficient portfolios is β = σp/σmkt
- Under this relation the CML agrees with the CAPM. This relation does not hold for inefficient portfolios
Formula for βi
βi = cov (ri, rm) / σ2m
OLS regression analysis for estimating beta
ri − rf = ai + bi (rm − rf ) + εi
If you assume a constant riskfree rate then, by the properties of OLS, specifically corr(rm, ϵi)=0, risk can be split into the following parts:
Sharpe Ratio formula
Sharpe Ratio = (Rp - Rf) / σm
Security Market Line (SML) - formula
ri = rf + βi * (rmkt − rf )
A security i’s alpha is defined as:
αi = E[Ri] − Rf − βi * (E[RM] − Rf )
Information Ratio (IR) - formula
- IR = αp / σ(ϵp)
- also known as the Appraisal ratio
- measures the extra return we can obtain
from security analysis
Treynor Ratio - formula
Tp = (E(rp)−rf) / βp
Constant (Gordon) Growth Model (simplified DDM) - P0 = …
P0 = D1 / (r − g)
Definition Return on equity (ROE) is defined as:
ROE = Earnings / Book value of equity
How is the reinvestment ratio of earnings also called?
The plowback ratio (or retention ratio) “b”
What is the payout ratio expressed as the plowback ratio?
1-b
Formula for “firm’s sustainable growth rate”:
g = Earnings_t+1 / Earnings_t − 1 = b ∗ ROE
P/E ratio expressed with r and b:
P/EPS = (1 − b) / (r − b × ROE)
Price-to-earnings ratio and future stock
returns - chart
low long-run growth rate (LLTG) vs high long-run growth rate (HLTG) stocks - performance - observation
- LLTG stocks appear undervalued and HLTG overvalued Observation
- LLTG portfolio earns a compounded average return of 15% in the year after formation, while the HLTG portfolio earns only 3%
- HLTG portfolio has higher market beta than the LLTG portfolio
Analyst biases/anomalies could also result from information frictions, such as:
- Sticky Information: It is costly to update forecasts frequently.
- Noisy Information: The available information contains significant noise, making it difficult to extract a clear signal about the forecasted variable.
- Rational Learning: Investors are rational but are still learning about the processes that dictate the variables being forecasted, and may not fully understand the underlying model yet