The Curve

by s7ven

Contango and backwardation

Contango describes a forward curve where contracts for later delivery trade above contracts for earlier delivery. Backwardation describes the opposite: later months priced below nearer ones.

What the curve is

A futures market does not quote one price. It quotes a series of them, one per delivery month, each a separate contract with its own order book. Plot those prices against their delivery dates and you get the forward curve. Its shape is not decorative. It is the market's collective statement about what it costs to hold the underlying between now and then, and about how badly anyone wants it right now.

The traditional starting point is the cost-of-carry relationship. Holding a physical commodity for six months means paying to store it, insure it and finance it. If a distant contract traded at the same price as the near one, the trade of buying now, storing, and delivering later would be free money, and that trade is available to anyone with a warehouse. Arbitrage pushes the distant contract up until the spread roughly covers the carrying cost. That upward-sloping shape is contango.

Backwardation inverts it, and it cannot be arbitraged away as easily, because the reverse trade requires borrowing the physical commodity rather than merely storing it. Its usual explanation is a convenience yield: someone who actually needs the commodity in hand now, a refinery, a mill, a manufacturer, will pay a premium for immediate delivery that no financial position can replicate. Tight supply pushes near-month prices above distant ones.

Two curve shapes compared One curve rises from left to right across six delivery months, labelled contango. A second curve falls from left to right across the same months, labelled backwardation. CONTANGO BACKWARDATION M1 M2 M3 M4 M5 M6
The same six delivery months under two regimes. Neither shape is bullish or bearish in itself; both describe the relationship between contracts, not the direction of the underlying.

Convergence

Whatever shape the curve takes, one thing is fixed: as a contract approaches expiry, its price and the spot price converge. They must, because at delivery the contract simply is the commodity. The difference between the two before that point is the basis, and the curve is in effect a map of how the basis is expected to decay.

Why it matters for anyone holding a position

A futures contract expires. Anyone maintaining exposure beyond that date has to close the expiring contract and open the next one, an operation called the roll. In contango, the next contract costs more than the one being sold. In backwardation, it costs less. Repeated across many rolls, that difference compounds, and it is the reason a futures-based product can drift away from the spot price it appears to track. This is a mechanical consequence of curve shape, not a flaw in anyone's execution.

The words themselves

Both terms predate modern futures exchanges and come from the London Stock Exchange of the nineteenth century, where they described fees paid to defer settlement of a transaction rather than properties of a commodity curve. Contango referred to a charge a buyer paid to postpone; backwardation to a charge a seller paid for the same privilege. The mechanics they described disappeared with the settlement system that produced them, and the words survived by being borrowed into commodity markets for a related but distinct idea.

John Maynard Keynes gave the pattern its best-known theoretical treatment in the 1920s, arguing that producers hedging future output would systematically sell forward at a discount to expected spot, and that speculators taking the other side earn that discount as compensation for risk. The idea is usually called normal backwardation, and it has been argued over for a century since.

A note on the numbers below

Contract specifications change. Every figure on this site carries a verification state, and anything marked unverified has not yet been checked against the exchange's own contract page. Treat unverified rows as a placeholder, not a fact.

Illustrative curve terminology by market unverified
TermNear monthDistant monthCommon driver
ContangolowerhigherStorage, insurance and financing costs
BackwardationhigherlowerConvenience yield, immediate scarcity
FlatequalequalCarry roughly offset by convenience yield

Limitations

  • Curve shape is not a forecast. It is frequently described as the market's expectation of future prices. It is closer to a description of present carrying costs and present scarcity, and it changes as those change.
  • Cost of carry does not apply uniformly. Financial futures on indices and rates have no storage cost, so their curves are driven by interest rates and dividends instead, and the physical intuition misleads.
  • The near month is noisy. The contract closest to expiry is subject to delivery mechanics and thinning liquidity that can distort the front of the curve in ways unrelated to the wider market.

Related: basis, rollover, open interest