Risk and return (w2) Flashcards
What is the difference between nominal and real interest rate?
Nominal = growth rate of money
Real = growth rate of purchising power
How is real interest rate (rr) calculated?
Real interest rate = (rn - i) / (1 + i)
What is the Fisher Equation?
rr = rn + E(i)
Denotes the relationship between demanded nominal rates and inflation
As expected inflation E(i) increases, so does the expectation for the nominal rate (rn) to minimise the decrease in real rate (rr)
To ensure the value of money does not decrease overall
How to calculate a risk free rate of return on a zero coupon bond?
Risk free return at time t=1
rf = face value / price at maturity -1
rf = fv / P(t) - 1
Face value = par value –> price received at maturity
How is holding period return determined?
HPR = (Price in period t1 - Price in period t0 + Dividends in t1) / Price in period 0
HPR = (P1 - P0 + D1) / P0
Why are long term, low-risk investment unattractive?
Because of the negative correlation between inflation and real interest rate, the nominal rate often does not compensate for the soaring inflation, decreasing the value of the investment
How are expected returns of an investment calculated? Why is it important to estimate those?
Expected return = sum of (probability x return) for all states
E(r) = Σp(s) * r(s)
Important as when entering an investment, future return is unknown = must be estimated
Expected return = weighted mean
You’ll need E(r)
How to calculate variance of an investment?
Var = sum of [probability * (return in state - expected return) ]
Var = Σ p(s) * [ r(s) - E(r) ]^2
Note: return for each state is adjusted by the expected return to track deviation around the mean
Note: because it is a variance, r(s) - E(r) is SQUARED to ensure all values are positive
Risk = deviation around the mean
How to calculate variance when probabilities are unknown? How to convert it into SD?
VAR = 1/n * Σ r(s)
SD = sqrt of var
note: for SD, n becomes n-1
SD = sqrt of final VAR equation
What is risk premium?
The difference between the return on a risk free asset r(f) and the risky investment
Calculated as a difference between the HPR of both
What is Sharpe Ratio?
Sharpe Ratio = risk premium / SD of excess return
Note: since the risk free asset has a SD = 0, SD of excess return = SD of a risky asset
Sharpe Ratio = the slope of CAL
How does SD measures risk?
SD measures volatility
Therefore, the lower the SD the safer the stock
–> If SD is present, positive SD is preferred
If SD > E(r)
–> Expected returns do not compensate for the risk
–> The returns can be expected to be negative
How to estimate investment returns using historical data?
Since future states and their probabilities are unknown
Expected return = sum of historical returns / number of time periods
E(r) = 1/n * Σ r(s)
Probabilities of scenarios are replaced with historical outcomes which are observable
Why is normal distribution of the returns important?
3 reasons
- If returns follow a normal distribution, SD is an accurate measure of risk
- If all security returns are symmetrical, so will be the return of the portfolio
–> E(r) and SD can be used for estimating scenarios
What are the 2 consequences of not normally distributed returns?
- SD does not reflect risk accurately
- Sharpe ratio no longer gives an accurate measure of portfolio performance