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Explore the fundamentals of risk and return in investing, including dollar returns, percentage returns, historical averages, and arithmetic versus geometric averages. Learn how to calculate and analyze risk premiums, variance, and standard deviation.
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1 Class Introduction and A Brief History of Risk and Return
Class Introduction • Class Expectations • Review of Syllabus • Text • Calculator • Grading • Assignments • Form Groups
Returns: Dollar and Percentage • Quick Review: • What is a return? • Dollar terms • Selling Price + Distributions – Buying Price = Dollar Returns • Percentage terms • Dollar Returns / Original Investment • Why do we like percentage returns? • Comparable across different investments
Dollar Returns • Total dollar returnis the return on an investment measured in dollars, accounting for all interim cash flows and capital gains or losses. • Problem 1 – 100 Shares of Stock • Buying Price $89 • Dividend Received during year $1.20 • Selling Price $97 Dollar Return Per Share $97.00 + $9.20 -$89.00 = $9.20
Percent Returns • Total percent returnis the return on an investment measured as a percentage of the original investment. • Problem 1 – 100 Shares of Stock • Buying Price $89 • Dividend Received during year $1.20 • Selling Price $97 Dollar Return = ($97 + $1.20) - $89 = $9.20 Percentage Return = $9.20 / $89 = 0.10337 or 10.34%
Historical Average Returns • A useful number to help us summarize historical financial data is the average. • Using the data in Table 1.1, if you add up the returns for large-company stocks from 1926 through 2005, you get about 984 percent. • Because there are 80 returns, the average return is about 12.3%. How do you use this number? • If you are making a guess about the size of the return for a year selected at random, your best guess is 12.3%. • The formula for the historical average return is:
Arithmetic Averages versusGeometric Averages • The arithmetic average return answers the question: “What was your return in an average year over a particular period?” • The geometric average return answers the question: “What was your average compound return per year over a particular period?” • How to calculate a geometric average. Geo Average = (Ending Value/Beg. Value)(1/n-1) – 1 where n is the number of years and n -1 is the number of returns • If you are working with returns you take the cumulative return Geo Average = (1+ Cumulative Return)(1/n) – 1
Example: Calculating a Geometric Average Return • Problem 5 Jurassic Jalopies and Stonehenge Construction • The spreadsheet below shows us the geometric average return.
Arithmetic Averages versusGeometric Averages • The arithmetic average tells you what you earned in a typical year. • The geometric average tells you what you actually earned per year on average, compounded annually. • When we talk about average returns, we generally are talking about arithmetic average returns. • For the purpose of forecasting future returns of more than one year: • The arithmetic average is probably "too high" for long forecasts. • The geometric average is probably "too low" for short forecasts. • Unless we match the investing horizon with the horizon we used for calculating the return. For example, if you take a ten-year history, calculate a ten-year geometric average then this is the right rate for predicting a ten-year return.
The Historical Record:Total Returns on Large-Company Stocks.
The Historical Record: Total Returns on Small-Company Stocks.
Return Variability: The Statistical Tools • The formula for return variance is ("n" is the number of returns): • Sometimes, it is useful to use the standard deviation, which is related to variance like this:
Return Variability Review and Concepts • Varianceis a common measure of return dispersion. Sometimes, return dispersion is also call variability. • Standard deviationis the square root of the variance. • Sometimes the square root is called volatility. • Standard Deviation is handy because it is in the same "units" as the average. • Normal distribution:A symmetric, bell-shaped frequency distribution that can be described with only an average and a standard deviation. • Does a normal distribution describe asset returns?
Historical Returns, Standard Deviations, and Frequency Distributions: 1926—2005
Frequency Distribution of Returns on Common Stocks, 1926—2005
Risk and Return • Risk-free rate:The rate of return on a riskless, i.e., certain investment. • Risk premium:The extra return on a risky asset over the risk-free rate; i.e., the reward for bearing risk. • By looking at Table 1.3, we can see the risk premium earned by large-company stocks was 8.5%. The T-Bill average return was 3.8% and the large company stocks average return was 12.3%.
Risk and Return • The risk-free rate represents compensation for just waiting. • Therefore, this is often called the time value of money. In your previous class (BA 340 or BA 360) this was the real rate of return and inflation. • First Lesson: If we are willing to bear risk, then we can expect to earn a risk premium, at least on average. • Second Lesson: Further, the more risk we are willing to bear, the greater the expected risk premium.
Useful Internet Sites • cgi.money.cnn.com/tools/millionaire/millionaire.html(millionaire link) • finance.yahoo.com(reference for a terrific financial web site) • www.globalfindata.com(reference for historical financial market data—not free) • www.robertniles.com/stats(reference for easy to read statistics review)