β is a measure of how a firm correlates to the market.
The higher the firm's debt, the more variable is its price and hence its β
Always assume given β is levered
If projects or leverage changes then we must adjust β
β = 1 (market)
β < 1 (risk of security is lower than average market)
β > 1 (risk of security is higher than average market risk)
If β is 0 there is no risk (government bond)
CAPM r
e
= r
f
+ β (r
m
- r
f
) OR r
f
+ (β X ERP)
Suppose RF is 5% and market risk premium is 7%.
Qantas has β of 1.33
According to CAPM what is expected return?
r
f
+ β (e
m
- r
f
) = 0.05 + 1.33 (0.07) = 14.31%
Therefore because qantas β of 1.33 investors will require a risk premium os 9.31% over RF rate.
Unleveling B.
B
u
= B
L
/ (1+ (1-t)((MV Debt)/(MV Equity)))
T is tax rate, B
L
is the observable levered β of equity (also known as project risk of a firm)
To reliever with new D/E ratio B
L
= B
u
(1 + (1-T) x (new D/new E)