Example 23.4
Hedging Market Risk
We also could approach the hedging problem in Example 23.4 using a similar regres-
sion procedure as that illustrated in Figure 23.3 for foreign exchange risk. The predicted
value of the portfolio is graphed in Figure 23.4 as a function of the value of the S&P 500
index. With a beta of .8, the slope of the relationship is 24,000: A 2.5% increase in the
index, from 1,000 to 1,025, results in a capital gain of 2% of $30 million, or $600,000.
Therefore, your portfolio will increase in value by $24,000 for each increase of one point
in the index. As a result, you should enter a short position on 24,000 units of the S&P 500
index to fully offset your exposure to marketwide movements. Because the contract multi-
plier is $250 times the index, you need to sell 24,000/250 5 96 contracts.
Notice that when the slope of the regression line relating your unprotected position to
the value of an asset is positive, your hedge strategy calls for a short position in that asset.
The hedge ratio is the negative of the regression slope. This is because the hedge position
should offset your initial exposure. If you do poorly when the asset value falls, you need
a hedge vehicle that will do well when the asset value falls. This calls for a short position
in the asset.
Active managers sometimes believe that a particular asset is underpriced, but that the
market as a whole is about to fall. Even if the asset is a good buy relative to other stocks
in the market, it still might perform poorly in a broad market downturn. To solve this
problem, the manager would like to separate the bet on the firm from the bet on the
market: The bet on the company must be offset with a hedge against the market exposure
that normally would accompany a purchase of the stock. In other words, the manager
seeks a market-neutral bet on the stock, by which we mean that a position on the stock
bod61671_ch23_799-834.indd 811
bod61671_ch23_799-834.indd 811
7/25/13 2:01 AM
7/25/13 2:01 AM
Final PDF to printer
812
P A R T V I
Options, Futures, and Other Derivatives
is taken to capture its alpha (its abnormal risk-adjusted expected return), but that market
exposure is fully hedged, resulting in a position beta of zero.
By allowing investors to hedge market performance, the futures contract allows the port-
folio manager to make stock picks without concern for the market exposure of the stocks
chosen. After the stocks are chosen, the resulting market risk of the portfolio can be modu-
lated to any degree using the stock futures contracts. Here again, the stock’s beta is the key
to the hedging strategy. We discuss market-neutral strategies in more detail in Chapter 26.
Predicted Value
of Portfolio
Slope
= 24,000
S&P 500
Index
$30.6 million
$30 million
1,000
1,025
Do'stlaringiz bilan baham: |