1. 2. 3. 4. 5.
Lợi nhuận :các khái niệm cơ bản Rủi ro: các khái niệm cơ bản Rủi ro riêng lẻ Rủi ro thị trường (rủi ro danh mục) Rủi ro và lợi nhuận: CAPM/SML
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Investment returns
The rate of return on an investment can be calculated as follows:
Return =
(Amount received – Amount invested) ________________________ Amount invested
For example, if $1,000 is invested and $1,100 is returned after one year, the rate of return for this investment is: ($1,100 - $1,000) / $1,000 = 10%.
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What is investment risk?
Two types of investment risk
Stand-alone risk Portfolio risk
Investment risk is related to the probability of earning a low or negative actual return. The greater the chance of lower than expected or negative returns, the riskier the investment.
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Probability distributions
A listing of all possible outcomes, and the probability of each occurrence. Can be shown graphically.
Firm X
Firm Y -70 0 15 100
Rate of Return (%)
Expected Rate of Return
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Selected Realized Returns, 1926 – 2004
Small-company stocks Large-company stocks L-T corporate bonds L-T government bonds U.S. Treasury bills Average Return 17.5% 12.4 6.2 5.8 3.8 Standard Deviation 33.1% 20.3 8.6 9.3 3.1
Source: Based on Stocks, Bonds, Bills, and Inflation: (Valuation Edition) 2005 Yearbook (Chicago: Ibbotson Associates, 2005), p28.
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Investment alternatives
Economy Prob. 0.1 0.2 0.4 0.2 0.1 T-Bill 5.5% 5.5% 5.5% 5.5% 5.5% HT -27.0% -7.0% 15.0% 30.0% 45.0% Coll 27.0% 13.0% 0.0% -11.0% -21.0% USR 6.0% -14.0% 3.0% 41.0% 26.0% MP -17.0% -3.0% 10.0% 25.0% 38.0%
Recession Below avg Average Above avg Boom
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Why is the T-bill return independent of the economy? Do T-bills promise a completely risk-free return?
T-bills will return the promised 5.5%, regardless of the economy. No, T-bills do not provide a completely risk-free return, as they are still exposed to inflation. Although, very little unexpected inflation is likely to occur over such a short period of time. T-bills are also risky in terms of reinvestment rate risk. T-bills are risk-free in the default sense of the word.
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How do the returns of HT and Coll. behave in relation to the market?
HT – Moves with the economy, and has a positive correlation. This is typical. Coll. – Is countercyclical with the economy, and has a negative correlation. This is unusual.
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Calculating the expected return
^
r = expected rate of return r = ∑ ri Pi i =1 ^ N
^
r HT = (-27%) (0.1) + (-7%) (0.2) + (15%) (0.4) + (30%) (0.2) + (45%) (0.1) = 12.4%
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Summary of expected returns
HT Market USR T-bill Coll. Expected return 12.4% 10.5% 9.8% 5.5% 1.0%
HT has the highest expected return, and appears to be the best investment alternative, but is it really? Have we failed to account for risk?
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Calculating standard deviation σ = Standard deviation σ = Variance = σ2 σ = (ri − ˆ)2 Pi r ∑ i =1 N
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Standard deviation for each investment σ= ∑ i =1
N
(ri − r ) 2 Pi
2 2
^
σ T − bills
(5.5 - 5.5) (0.1) + (5.5 - 5.5) (0.2) = + (5.5 - 5.5)2 (0.4) + (5.5 - 5.5)2 (0.2) + (5.5 - 5.5)2 (0.1)
1
2
σ T − bills = 0.0% σ HT = 20.0%
σ Coll = 13.2% σ USR = 18.8% σ M = 15.2%
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Comparing standard deviations
Prob. T - bill
USR HT
0
5.5 9.8
12.4
Rate of Return (%)
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Comments on standard deviation as a measure of risk
Standard deviation (σi) measures total, or stand-alone, risk. The larger σi is, the lower the probability that actual returns will be closer to expected returns. Larger σi is associated with a wider probability distribution of returns.
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Comparing risk and return
Security T-bills HT Coll* USR* Market
* Seem out of place.
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Expected return, ^ r 5.5% 12.4% 1.0% 9.8% 10.5%
Risk, σ 0.0% 20.0% 13.2% 18.8% 15.2%
Coefficient of Variation (CV)
A standardized measure of dispersion