LM1 Time value of money Flashcards
What are the 3 ways that interest rates (r) can be thought of?
- Required rate of return
- Discount rate
- Opportunity cost
What are the 5 continuously changing determinants of interest rates?
- Real default risk-free rate (over a single period)
- Inflation premium
- Default risk premium
- Liquidity premium
- Maturity premium
What is the maturity premium?
Compensation for greater price sensitivity from changes in rates
What is pi^e?
The default risk-free rate plus the inflation premium
Over what time period are interest rates quoted?
Always annual
How do you calculate holding period return?
R = [(ending price - beginning price) + all income] / beginning price
How do you calculate multi-period holding period of return?
- Find the return for each holding period
- add 1 to each
- multiply them together
- subtract 1 at the end
How do you calculcate arithmetic return?
Add up all your returns and divide by T
How do you calculate geometric mean return?
- Take return from each period and add 1
- Multiply them together
- Put the number to the power of 1/T
- Subtract 1
When is the geometric mean equal to the arithmetic mean?
When all observations are equal. When there is variability, GM < AM
When would you use a geometric mean return?
When looking at a return over a number of periods.
This is because if you compound the arithmetic mean it does NOT equal the return over multiple periods
How do you get from the formula for arithmetic mean to the one for harmonic mean?
AM = sum(x) / n
- Invert the x:
sum(1/x) / n
- Invert the whole fraction:
n / sum(1/x)
Why is harmonic mean useful for reducing the effect of outliers?
- Observation weight is inversely proportional to its magnitude for HM.
- Therefore it reduces the effect of outliers
How can harmonic mean be used to deal with dollar cost averaging?
- Helps calculate average cost per share
- if you average the prices paid per share using AM you don’t get to the true average price
If I have a 6% trimmed mean and an untrimmed set of 200 observations, how many would I have in my yrimemd set?
176
200 - (6% x 2 x 200)