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Document Date: November 2, 2006
An Introduction To Derivatives And Risk Management , 7th
Edition
Don Chance and Robert Brooks
Technical Note: Futures Risk Premiums, Ch. 9, p. 309
This technical note supports the material in the Asset Risk Premium Hypothesis
section of Chapter 9 Principles of Pricing Forwards, Futures, and Options on Futures.
We explore here the relationship between futures prices and expected spot prices under
various assumptions about market microstructure. Insights are supported with
observations from the gold, copper and natural gas futures markets.
Futures prices and expected spot prices
We explore the relationship between spot asset prices and futures or forward
contracts when arbitrage is and is not possible. We do not distinguish between forwardor futures markets here.
Asset Price in Secondary Market
The price of the spot asset ( ) could be represented as the present value of the
expected future asset value (
0S
( )T0 SE ) adjusted for any holding costs (future value of
storage, insurance and such), any benefits (convenience yield, dividends, and such) (all
carry costs are denoted ), and a spot asset risk premium (θ ( )T0,S Sφ ), expressed as:
( ) ( )T0,ST00 SSES φ−θ−=
Using a standard supply and demand graph, we illustrate this result in Figure 1.
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Figure 1. Asset Supply and Demand Curves
Price
Asset Supply
Asset Demand
E0[PA]
PA
QA Quantity
Insights:
• The clearing price and quantity are determined by asset supply and demand in the
secondary asset market
• The asset price is the present value of expected future cash flows, discounted at a
risk adjusted discount rate
Net Hedging: A Digression
It is reasonable to assume that hedgers are willing to pay a futures risk premium
to reduce their risk. Figure 2 illustrates the net hedging theory when net hedgers are long.
The phrase net hedger is used because in any futures market there are typically hedgers
on both the long and short side of the market. One can add up all the hedgers that are long
and all the hedgers that are short. Subtracting these two totals, one can determine whether
a particular futures contract has net long or net short hedgers. These net hedgers are long
the futures contracts and are willing to contract at futures prices above the expected
future spot price. Net speculators provide the hedging protection for a futures risk
premium above the expected future spot price. This market is said to be in normal
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contango as the futures price is above the unobservable expected future spot price. The
figure below illustrates the case where net hedgers are long and speculators demand a risk
premium.
Figure 2. Net Positions of Hedgers and Speculators when Net Hedgers are long:
Normal Contango
0,f φ
Equilibrium Futures Price
Net Hedgers
Net Speculators
Expected Future Spot Price
Futures Price
Short Contracts Long Contracts
Recall that hedgers are willing to pay a premium to reduce their risk. If net
hedgers are short the futures contract they are willing to hedge at futures prices below the
expected future spot price. Net speculators will provide the hedging protection for a
futures risk premium below the expected future spot price. This market is said to be in
normal backwardation as the futures price is below the unobservable expected future spot
price, illustrated in Figure 3.
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Figure 3. Net Positions of Hedgers and Speculators when Net Hedgers are short:
Normal Backwardation
Futures Price
0,f φ
Equilibrium Futures Price
Net Hedgers Net Speculators
Expected Future
S ot Price
Short Contracts Long Contracts
Futures Price in Unarbitraged Derivatives Market
The price of the futures contract on the spot asset could be represented as the
expected future asset value adjusted for any holding costs (margin, impact of marking-to-
market and such), any benefits (embedded options and such), and a futures risk premium
(which could be positive or negative depending on net hedging demand):
( ) ( ) ( )T0,f T00 SSETf φ−θ−=
Assuming no holding costs or benefits from having a position in the futures market,
( ) ( ) ( )T0,f T00 SSETf φ−=
Thus, in an unarbitraged market we expect to find that the futures price is a function of
the expected future spot asset value adjusted for perhaps a significant futures risk
premium. Figure 4 depicts equilibrium in a futures markets where arbitrage is not
feasible.
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Figure 4. Equilibrium in Unarbitraged Futures Market
Insights:
• Speculators must earn a positive risk premium to be induced to participate
• Hedgers are assumed to be net long
• The difference between the futures price and the expected future asset price is the
compensation to the speculator (futures risk premium)
• Greater hedging demand results in higher compensation to speculators
• The difference between expected the future spot asset price and today’s asset
price depends on both the risk-free rate and any asset risk premiums
Futures Price in Fully-Arbitraged Derivatives Market
Recall that only when the futures market is fully arbitraged, we have
( ) θ+= 00 STf .
Solving for the future value of costs and benefits and substituting this result into the spot
price equation, we have:
( ) ( )T0,ST00 SSES φ−θ−= .
Hedger Demand – Net Long
Speculator Supply – Net ShortPrice
PF,UA E0[PA]
PA
QF,UA QA Quantity
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Thus substituting S0,
( ) ( ) ( )T0,ST00 SSETf φ−= .
Thus, the futures price does not equal the expected future asset price. This equation is a
direct outcome, however, of assuming the market is arbitrage-free and there are no
market imperfections. Every derivatives market has some imperfections and hence this
result is not exactly correct. Figure 5 illustrates both the unarbitraged case and the fully
arbitraged case.
Figure 5. Equilibrium in Unarbitraged and Arbitraged Futures Market
Insights:
• A fully arbitraged futures market implies that the futures price is equal to the
future value of the asset price, adjusted for the marginal dealer’s cost of funds
(“risk-free” interest rate).
• The difference between the current futures price and the expected future asset
price is the asset’s risk premium.
• The difference between the quantity of long futures positions in a fully-arbitraged
market and the quantity of long futures positions in an unarbitraged market
represents the net additional supply of short contracts provided by arbitragers
Hedger Demand – Net Long
PF,A = FV[PA]
E0[PA]
Speculator Supply – Net ShortPrice
PF,UA
PA
QF,UA QA QF,FA Quantity
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• Arbitrageurs, however, are net short futures contracts and will hence buy the same
amount of the underlying asset, driving the asset price up, resulting in less
demand by arbitrageurs.
• Assuming the asset market price does not materially change, the difference
between the quantity of long futures positions in a fully-arbitraged market and the
quantity of long futures positions in an unarbitraged market represents the net
societal benefit from satisfying greater hedging demand.
• There is no futures risk premium in fully arbitraged futures markets.
• The futures price reflects the asset risk premium (the difference between the
expected future asset price and current futures price).
Based on the analysis above, futures markets can be classified into three types, fully-
arbitraged, quasi-arbitraged, and un-arbitraged. In a futures market that is fully-
arbitraged, both carry arbitrage and reverse-carry arbitrage can be conducted by a wide
array of market participants. In a futures market that is quasi-arbitraged, either carry
arbitrage or reverse-carry arbitrage can be conducted by a wide array of market
participants, but not both. In a futures market that is un-arbitraged, neither carry arbitrage
nor reverse-carry arbitrage can be conducted by market participants.
Market Classification Illustrated
Fully-Arbitraged Market
One characteristic of a fully arbitraged market is the stochastic nature of futures
contracts that differ only by maturity. Assuming the carry model, the percentage
difference in futures prices of different maturities is: (denoted %TP for percentage term
premium)
( ) ( )( )
( )
1
S
SS
Tf
Tf Tf TP%
T
T
T0
T0T0
0
00
−θ
θ=
θ+
θ+−θ+=
−τ+=
τ+
τ+
.
Notice that the difference in futures prices depends solely on the difference in the
maturity and the carry costs. We assume the longer time to maturity, the higher the carry
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costs. Hence, one would expect that at a point in time, the percentage difference in
futures prices would be slightly positive and stable. Figure 6 illustrates gold futures
contracts. Since 1985 gold futures contracts exhibit the characteristics common for fully-
arbitraged markets. In the late 1970s and early 1980s there appeared some evidence that
gold futures were not fully arbitraged. For example, at the end of 1979 and in early 1980,
there were periods of time when the percentage term premium was large and both
positive and negative.
A large positive term premium implies a profitable arbitrage trade: enter a long
position in the distant contract and a short position in the near contract. When the near
contract expires, buy the underlying asset with borrowed money and deliver it when the
distant contract expires.
A large negative term premium implies a profitable arbitrage trade: enter a short
position in the distant contract and a long position in the near contract. When the near
contract expires, short sell the underlying asset and lend money and cover the short
position when the distant contract expires.
Figure 6. Term Premium for Gold Futures
-20.00%
-15.00%
-10.00%
-5.00%
0.00%
5.00%
10.00%
15.00%
20.00%
Jan-75 Jan-77 Jan-79 Dec-80 Dec-82 Dec-84 Dec-86 Dec-88 Dec-90 Dec-92 Dec-94 Dec-96 Dec-98 Dec-00
Calendar Time
P e r c e n t a g e P r e m i u m
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Quasi-Arbitraged Market
A quasi-arbitrage market is rare to find. One side of the carry arbitrage must be
feasible, whereas the other is not. The copper futures market during the late 1980s and
mid-1990s fit this classification scheme. Figure 7 illustrates the copper futures market.
Notice that apparent ceiling in the percentage term premium. There are large negative
term premiums but not large positive term premiums.
In the copper market, by the late 1980s traders apparently had entered the copper
arbitrage business. Recall, a large positive term premium implies a profitable arbitrage
trade: enter a long position in the distant contract and a short position in the near contract.
When the near contract expires, buy the underlying asset with borrowed money and
deliver it when the distant contract expires. The only requirement is to be able to store
copper cheaply, not a difficult task.
Short-selling copper, however, is more difficult. By 1997, firms with an inventory
of copper apparently entered the reverse carry arbitrage business. Recall a large negative
term premium implies a profitable arbitrage trade: enter a short position in the distant
contract and a long position in the near contract. When the near contract expires, short
sell (or sell out of inventory) the underlying asset and lend money and cover the short
position when the distant contract expires. Apparently, by 1997 both sides of the carry
arbitrage were feasible, and hence copper graduated to a fully-arbitraged futures market.
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Figure 7. Term Premium for Copper Futures
-20.00%
-15.00%
-10.00%
-5.00%
0.00%
5.00%
10.00%
15.00%
20.00%
Jan-75 Jan-77 Jan-79 Dec-80 Dec-82 Dec-84 Dec-86 Dec-88 Dec-90 Dec-92 Dec-94 Dec-96 Dec-98 Dec-00
Calendar Time
P e r c e n t a g e P r e m i u m
Un-Arbitraged Market
This type of market is easy to find. Neither side of the carry arbitrage is feasible.
The natural gas futures market fits this classification scheme at this time, as illustrated in
Figure 8. Notice that the percentage term premium can vary dramatically.
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Figure 8. Term Premium for Natural Gas Futures
-20.00%
-15.00%
-10.00%
-5.00%
0.00%
5.00%
10.00%
15.00%
20.00%
Jun-93 Jun-94 Jun-95 May-96 May-97 May-98 May-99 May-00 May-01 May-02 May-03
Calendar Time
P e r c e n t a g e P r e m i u m
Valuation models need to be tailored to the category of futures market. A fully-
arbitraged market would apply a carry model for valuation purposes. The carry model is
solely dependent on the cost of carrying the underlying asset through time and the
appropriate discount rate. The quasi-arbitrage market would apply the carry model for
valuation purposes at some times and not at others. The un-arbitraged market requires an
entirely different approach to valuation.
References
Black, F. “The Pricing of Commodity Contracts.” Journal of Financial
Economics 3 (1976), 167-179.
French, K. R. “Detecting Spot Price Forecasts in Futures Prices.” The Journal of
Business 59 (1983), S39-S54.
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