CHAPTER EIGHT
RISKFREE LENDING
AND BORROWING
DEFINING THE RISK FREE ASSET
WHAT IS A RISK FREE ASSET?
•
DEFINITION: an asset whose terminal value is certain
variance of returns = 0,
covariance with other assets = 0If
then
i 0
j i ij
ij
DEFINING THE RISK FREE ASSET
DOES A RISK FREE ASSET EXIST?
•
CONDITIONS FOR EXISTENCE:
Fixed-income security
No possibility of default
No interest-rate risk
no reinvestment riskDEFINING THE RISK FREE ASSET
DOES A RISK FREE ASSET EXIST?
•
Given the conditions, what qualifies?
a U.S. Treasury security with a maturity matching the investor’s horizonRISK FREE LENDING
ALLOWING FOR RISK FREE LENDING
•
investor now able to invest in either or both,•
a risk free and a risky assetRISK FREE LENDING
ALLOWING FOR RISK FREE LENDING
•
the addition expands the feasible set•
changes the location of the efficient frontier•
assume 5 hypothetical portfoliosTHE EFFECT OF RISK FREE LENDING ON THE EFFICIENT SET
INVESTING IN BOTH: RISKFREE AND RISKY ASSET
PORTFOLIOS X1 X2 ri
A.00 1.0 4 0
B .25 .75 7.05 3.02
C .50 .50 10.10 6.04 D .75 .25 13.15 9.06
E 1.00 .00 16.20 12.08
THE EFFECT OF RISK FREE LENDING ON THE EFFICIENT SET
RISKY AND RISK FREE PORTFOLIOS
A
D
rRF = 4%
Pr
P0
C B
E
THE EFFECT OF RISK FREE LENDING ON THE EFFICIENT SET
IN RISKY AND RISK FREE PORTFOLIOS
•
All portfolios lie on a straight line•
Any combination of the two assets lies on a straight line connecting the risk free asset and the efficient set of the risky assetsTHE EFFECT OF RISK FREE LENDING ON THE EFFICIENT SET
The Connection to the Risky Portfolio
r
P
THE EFFECT OF RISK FREE LENDING ON THE EFFICIENT SET
THE EFFECTS OF RISK FREE LENDING ON THE EFFICIENT SET
•
Two Boundaries Result
a line emanating from the risk free rate to the risk portfolio B(line segment r B)
a combination of risky assets with various weights(line segment r T)
there will be no efficient combined portfolioTHE EFFECT OF RISK FREE LENDING ON THE EFFICIENT SET
TWO NEW BOUNDARIES
T B
r
Pr
P0
THE EFFECT OF RISK FREE LENDING ON THE EFFICIENT SET
FOR RISK AVERSE
Portfolio A is the optimal A
r
P
THE EFFECT OF RISK FREE LENDING ON THE EFFICIENT SET
FOR RISK LOVER
B
Pr
PPortfolio B
is the optimal
0