1、Risk and Return: Lessons from Market History,Chapter 10,Copyright 2010 by the McGraw-Hill Companies, Inc. All rights reserved.,McGraw-Hill/Irwin,Key Concepts and Skills,Know how to calculate the return on an investment Know how to calculate the standard deviation of an investments returns Understand
2、 the historical returns and risks on various types of investments Understand the importance of the normal distribution Understand the difference between arithmetic and geometric average returns,Chapter Outline,10.1 Returns 10.2 Holding-Period Returns 10.3 Return Statistics 10.4 Average Stock Returns
3、 and Risk-Free Returns 10.5 Risk Statistics 10.6 More on Average Returns 10.7 The U.S. Equity Risk Premium: Historical and International Perspectives,10.1 Returns,Dollar Returns the sum of the cash received and the change in value of the asset, in dollars.,Percentage Returns the sum of the cash rece
4、ived and the change in value of the asset, divided by the initial investment.,Dollar Return = Dividend + Change in Market Value,Returns,Returns: Example,Suppose you bought 100 shares of Wal-Mart (WMT) one year ago today at $45. Over the last year, you received $27 in dividends (27 cents per share 10
5、0 shares). At the end of the year, the stock sells for $48. How did you do? You invested $45 100 = $4,500. At the end of the year, you have stock worth $4,800 and cash dividends of $27. Your dollar gain was $327 = $27 + ($4,800 $4,500). Your percentage gain for the year is:,Returns: Example,Dollar R
6、eturn: $327 gain,Percentage Return:,10.2 Holding Period Return,The holding period return is the return that an investor would get when holding an investment over a period of T years, when the return during year i is given as Ri:,Holding Period Return: Example,Suppose your investment provides the fol
7、lowing returns over a four-year period:,Historical Returns,A famous set of studies dealing with rates of returns on common stocks, bonds, and Treasury bills was conducted by Roger Ibbotson and Rex Sinquefield. They present year-by-year historical rates of return starting in 1926 for the following fi
8、ve important types of financial instruments in the United States: Large-company Common Stocks Small-company Common Stocks Long-term Corporate Bonds Long-term U.S. Government Bonds U.S. Treasury Bills,10.3 Return Statistics,The history of capital market returns can be summarized by describing the: av
9、erage returnthe standard deviation of those returns the frequency distribution of the returns,Historical Returns, 1926-2007,Source: Stocks, Bonds, Bills, and Inflation 2008 Yearbook, Ibbotson Associates, Inc., Chicago (annually updates work by Roger G. Ibbotson and Rex A. Sinquefield). All rights re
10、served., 90%,+ 90%,0%,Average Standard Series Annual Return Deviation Distribution Large Company Stocks 12.3% 20.0% Small Company Stocks 17.1 32.6 Long-Term Corporate Bonds 6.2 8.4 Long-Term Government Bonds 5.8 9.2 U.S. Treasury Bills 3.8 3.1 Inflation 3.1 4.2,10.4 Average Stock Returns and Risk-Fr
11、ee Returns,The Risk Premium is the added return (over and above the risk-free rate) resulting from bearing risk. One of the most significant observations of stock market data is the long-run excess of stock return over the risk-free return. The average excess return from large company common stocks
12、for the period 1926 through 2007 was: 8.5% = 12.3% 3.8% The average excess return from small company common stocks for the period 1926 through 2007 was: 13.3% = 17.1% 3.8% The average excess return from long-term corporate bonds for the period 1926 through 2007 was: 2.4% = 6.2% 3.8%,Risk Premiums,Su
13、ppose that The Wall Street Journal announced that the current rate for one-year Treasury bills is 2%. What is the expected return on the market of small-company stocks? Recall that the average excess return on small company common stocks for the period 1926 through 2007 was 13.3%. Given a risk-free
14、rate of 2%, we have an expected return on the market of small-company stocks of 15.3% = 13.3% + 2%,The Risk-Return Tradeoff,10.5 Risk Statistics,There is no universally agreed-upon definition of risk. The measures of risk that we discuss are variance and standard deviation. The standard deviation is
15、 the standard statistical measure of the spread of a sample, and it will be the measure we use most of this time. Its interpretation is facilitated by a discussion of the normal distribution.,Normal Distribution,A large enough sample drawn from a normal distribution looks like a bell-shaped curve.,P
16、robability,Return on large company common stocks,99.74%, 3s 47.7%, 2s 27.7%, 1s 7.7%,0 12.3%,+ 1s 32.3%,+ 2s 52.3%,+ 3s 72.3%,The probability that a yearly return will fall within 20.0 percent of the mean of 12.3 percent will be approximately 2/3.,68.26%,95.44%,Normal Distribution,The 20.0% standard
17、 deviation we found for large stock returns from 1926 through 2007 can now be interpreted in the following way: If stock returns are approximately normally distributed, the probability that a yearly return will fall within 20.0 percent of the mean of 12.3% will be approximately 2/3.,Example Return a
18、nd Variance,Variance = .0045 / (4-1) = .0015 Standard Deviation = .03873,10.6 More on Average Returns,Arithmetic average return earned in an average period over multiple periods Geometric average average compound return per period over multiple periods The geometric average will be less than the ari
19、thmetic average unless all the returns are equal. Which is better? The arithmetic average is overly optimistic for long horizons. The geometric average is overly pessimistic for short horizons.,Geometric Return: Example,Recall our earlier example:,So, our investor made an average of 9.58% per year,
20、realizing a holding period return of 44.21%.,Geometric Return: Example,Note that the geometric average is not the same as the arithmetic average:,Perspectives on the Equity Risk Premium,Over 1926-2007, the U.S. equity risk premium has been quite large: Earlier years (beginning in 1802) provide a sma
21、ller estimate at 5.4% Comparable data for 1900 to 2005 put the international equity risk premium at an average of 7.1%, versus 7.4% in the U.S. Going forward, an estimate of 7% seems reasonable, although somewhat higher or lower numbers could also be considered rational,Quick Quiz,Which of the investments discussed has had the highest average return and risk premium? Which of the investments discussed has had the highest standard deviation? Why is the normal distribution informative? What is the difference between arithmetic and geometric averages?,
