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Investing 101. Lecture 4 Basic Portfolio Building. Review. Explain supply and demand? What is GDP? What are Consumer/Producer surplus? Reservation Price? What is an interest rate? What is an exchange rate?. Does anyone have anything to share?. Stock update?
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Investing 101 Lecture 4 Basic Portfolio Building
Review • Explain supply and demand? • What is GDP? • What are Consumer/Producer surplus? Reservation Price? • What is an interest rate? • What is an exchange rate?
Does anyone have anything to share? • Stock update? • Anything special happening in life? • Anyone have any questions on unrelated random financial topics? • I don’t expect to get through all of today’s material in two hours, may stay 15 min and/or go into next day.
Main Teaching Points • Variance and standard deviation • Security market line (SML) • Capital allocation line (CAL) • Capital assets pricing model (CAPM) • Covariance and correlation • Diligent asset allocation • Pulling it all together.
Warning • There are lots of slides in today’s class. • Many of them are pictures and graphs. • If you are a spatial mathematician you will want to pay close attention. • There are some eqns you do NOT have to understand them, so if they confuse you do your best to block them out. • Lets get started we have A LOT to learn and much to pull together.
Empirical Rule • Has anyone heard of it??? • 68 95 99 • The key to risk in stocks.
The Security Market Line Risk GOOG SBUX TELUS Return Risk Free
Asset Allocation • Asset Allocation is the portfolio choice among broad investment classes: • One risky asset and one risk-free asset • Two risky assets • Two risky assets and one risk-free asset • Many risky assets and one risk-free asset
Asset Classes • Risky Assets • Stocks (S&P Comp. Index) • Mean Real Return: 10% • Standard Deviation: 20% • Bonds • Mean Real Return: 4% • Standard Deviation: 10% • Correlation with Real Stock Return: 0.2 • T-Bills (Risk-free asset) • Real Return: 1%
Portfolio of Risk-Free Asset and Risky Asset • What is the expected return and the standard deviation of a portfolio that invests: • w in stocks • 1-w in the risk-free asset?
Capital Allocation Line • Expected Return of Portfolio: • Standard Deviation of Portfolio: • Substituting for w, gives the Capital Allocation Line (CAL):
Capital Allocation Line E(r) P r f r 0
Capital Allocation Line E(r) The Capital Allocation Line P r Slope = E (rp) - rf f rp r 0
Capital Allocation Line • The Capital Allocation Line shows the risk-return combinations available by changing the proportion invested in a risk-free asset and a risky asset • The slope of the CAL is the reward-to-variability ratio
Capital Assets Pricing Model • Now that we know that different stocks hold different levels of risk, we can use this knowledge to price the stocks. • We use CAPM to find the rate at which to discount the future dividends of a stock. • Perpetuity stock = D1/k • Growth stock = D1/k-g • Where D = dividend, g = growth, k = discount rate.
CAPM Equation • k = rf + B(Rm-rf) • Where rf = Risk free rate Rm = Return of the market and B = beta. • Beta is the correlation b/w the returns of the market and the returns of the stock.
R stock RMkt
Risk Aversion • Now the question is, which risk-return combination along the CAL do you want? • To answer this we need to bring your preferences for risk into the picture • We will use indifference curves to represent risk aversion • Indifference curves represent utility functions
Indifference Curves u=3 E(r) u=2 B u=1 A N Van C Surrey r 0
Asset Allocation • Now we can combine the indifference curves with the capital allocation line • If investors are maximizing their utility, they will choose the highest possible indifference curve • The highest curve is tangent to the CAL
Asset Allocation E(r) CAL P Indifference Curves r f r 0
Portfolio Frontier • The portfolio frontier depicts the feasible portfolio choices for investors holding stocks and bonds • The minimum variance portfolio includes 86% bonds and 14% stocks • Portfolios below the minimum variance portfolio are inefficient • The portfolio frontier above the minimum variance portfolio is called ‘efficient frontier’
Correlation: Two Risky Assets • To see the importance of correlation, we will look at the set of feasible portfolios under three different assumptions: • 1) ρAB = 1 • 2) ρAB = -1 • 3) ρAB = 0 • Then we will discuss the intermediate cases
Perfect Correlation E(r) A B (r) 0
Perfect Correlation E(r) A = 1 AB B (r) 0
Perfect Negative Correlation E(r) A =1 AB B = -1 AB (r) 0
No Correlation E(r) = 0 AB A = 1 AB B = -1 AB (r) 0
Asset Allocation with Risk-Free Asset • Introducing a risk-free asset besides stocks and bonds improves the investment opportunities
Diversification • “It is part of a wise man … not to venture all his eggs in one basket” - Miguel de Cervantes • “Put all your eggs in one basket and watch that basket” - Mark Twain
The variance of the return of a portfolio that includes N different assets depends on the weight w and on the covariances : The Benefits of Diversification
Diversification • The standard deviation of a portfolio tends to decrease as more risky assets are added to the portfolio Std. Deviation Of Portfolio Firm-specific Risk Market Risk Number of Securities