Futures Contract vs Arbitrage
Futures Contract and Arbitrage are two Financial Markets & Investing concepts in AP Economics that students often mix up. A futures contract is an agreement to buy or sell an asset at a set price on a specific future date. Arbitrage is buying an asset in one market while selling the same asset at a higher price in another, locking in a profit with no exposure to price moves. Here is how they compare side by side.
Farmers and airlines use futures to lock in prices and hedge against swings in commodities like grain or oil. Speculators trade them to profit from price changes. They are standardized and traded on exchanges.
A true arbitrage needs the same asset, or two bundles that are economically identical, priced differently at the same moment. The trader buys where it is cheap and sells where it is dear in one motion, so the position closes immediately and the profit does not depend on which way prices go next. Those trades themselves push the low price up and the high price down, which is why observable gaps are small, short-lived and mostly captured by fast automated traders. This mechanism enforces the law of one price and keeps currency cross rates consistent with each other. Arbitrage is not speculation: a speculator holds a position and bears the risk of the price moving, while an arbitrageur is hedged by construction.
Futures vs Arbitrage: The Contract Against the Strategy That Prices It
| Futures Contract | Arbitrage | |
|---|---|---|
| What it is | A standardised contract with a set price and delivery date | A strategy of buying and selling the same value at two prices |
| Risk carried | Directional, and losses can run past the margin posted | Close to none in the textbook case, since both legs lock in together |
| Positions required | One leg is enough to hold a view | At least two, opened at the same moment |
| Source of the profit | The underlying moving your way | The gap between two prices, whichever way the market goes |
| Effect on prices | Adds one more buyer or seller at the going price | Closes the gap it feeds on, then has nothing left to do |
| Who uses it | Hedgers, speculators and arbitrageurs alike | Traders with low costs and fast execution |
| How long the chance lasts | The contract runs until its delivery date | Only until enough traders act on the same gap |
Arbitrage is what forces a futures price to equal spot plus the cost of carry
Suppose a storable commodity trades at 60 in the spot market, and financing plus storage for six months costs 4 a unit. The fair six-month contract price is therefore 64. If the contract instead trades at 70, an arbitrageur buys a unit at 60, funds and stores it for 4, and simultaneously sells the futures at 70, then delivers at expiry. The profit is 70 less 64, or 6 a unit, and it is fixed the instant both legs are open no matter what the spot price does afterwards. That same trade is what removes the opportunity, since buying spot pushes 60 upward while selling futures pushes 70 downward until the gap narrows back to the 4 that carrying costs justify. Run it the other way when the contract is too cheap. At a quoted 61 the locked-in gain is 3 a unit, though this version needs someone able to sell the physical unit short, which is harder than storing one, and that asymmetry is why underpriced contracts can persist longer than overpriced ones. The general form is worked through at /calculate/arbitrage-profit.
Convergence at expiry is what makes the pair riskless, and it is what most fake arbitrages are missing
The trade closes cleanly because on delivery day the contract and the asset become the same position, so the two prices must meet. Any gap surviving that moment would be free money for whoever bought the cheaper one and settled immediately. The difference between the two prices, called the basis, therefore narrows toward zero as the date approaches. Everything that resembles arbitrage without being it fails one of the conditions. Buying a contract expiring in three months while selling one expiring in nine is a bet on the shape of the curve, not a locked pair, because the legs settle at different times against different spot prices. Costs count too, since a quoted gap of 6 is only real if the spread, the financing and the storage all fit inside the 4 you assumed. Timing counts as well, because a hedged pair can still be closed out early by a margin call if the futures leg moves against you before delivery pays you back. Some underlyings cannot be carried at all, so the link is weak by nature: electricity has no cheap storage, and its contract prices reflect expected conditions on the delivery day rather than spot plus carry. The claim behind /glossary/efficient-market-hypothesis is not that gaps never open, only that watchers close them quickly.
Frequently asked questions
Is trading futures a form of arbitrage?
Rarely. Holding one futures position is a directional bet, since you profit when the underlying moves your way and lose when it does not. Arbitrage needs at least two positions opened together whose combined value is fixed regardless of direction. The same contract serves either purpose, which is the point worth carrying away: the instrument does not decide the strategy, the combination of positions around it does.
What determines the fair price of a futures contract?
The spot price plus the cost of carrying the asset to delivery, meaning financing and storage, less any income the asset throws off in the meantime. A commodity at 60 with 4 of carry over six months implies a fair contract price of 64. When the quoted price strays far from that figure, someone can lock in the difference, and the act of locking it in drags the two prices back toward each other.
Why do futures and spot prices converge at expiry?
Because on the delivery date the contract obliges an exchange of the asset at the contract price, so holding the contract and holding the asset amount to the same thing. Any surviving gap would hand free money to whoever bought the cheaper of the two and settled at once. The basis, meaning the difference between the two prices, therefore shrinks toward zero as the delivery date gets closer.
Related comparisons
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