Short answer — Between two comparable futures observed at the same instant, there is contango when the farther expiry is priced above the nearer one and backwardation when it is priced below. The definition applies to the stated segment: it is not equivalent to bullish or bearish and does not guarantee either the sign of roll yield or the final return.
Let T₁ < T₂ be two expiries and F(t,T₁), F(t,T₂) their prices at the
same timestamp t. Define the calendar spread as far minus near:
S₁,₂(t) = F(t,T₂) − F(t,T₁)S₁,₂ > 0: contango on theT₁ → T₂segment;S₁,₂ < 0: backwardation on the same segment;S₁,₂ = 0: flat segment at the precision being used.
The convention must be stated: a desk can quote the spread in the opposite order, reversing its sign without changing the economic relationship.
Why the segment must be stated
Saying that “the market is in contango” without naming the contracts, date and time discards information. A futures curve can rise between the front month and second month, fall between the second and third, and rise again farther out. That is a mixed curve, not a contradiction.
The comparison requires the same underlying and compatible specifications. Grade, delivery location, unit, currency, settlement mechanism and operating windows can turn a contractual difference into apparent slope. A thinly traded front month or one near first notice day can also produce a reading that does not represent the most actively traded part of the curve.
A comparison with spot price instead belongs to futures basis. On this page, contango and backwardation concern two futures expiries. Keeping the two relationships separate prevents one word from being used for measures with different references.
Curve shape, not a directional forecast
Contango does not automatically mean “the market will rise”; backwardation does not automatically mean “it will fall.” Futures prices are current contractual quotations. They can reflect carry, immediate availability, hedging flows, operating constraints and risk premia, not just an estimate of future spot.
For a storable commodity, an instructional cost-of-carry model is:
F(t,T) ≈ Sₜ × e^[(r + u − y) × τ]Here r represents financing, u proportional costs such as storage and
insurance, y convenience yield and τ time to expiry. If r + u − y is
positive, the model tends to produce higher prices for farther expiries; if
immediate availability has high economic value, the relationship can reverse.
This is a model, not a universal law. Seasonality, goods that cannot be stored perfectly, delivery grade and location, storage capacity, inventories, limits to arbitrage and hedging demand can dominate the relationship. The relevant cash flows and conventions differ for equity indices, currencies and rates.
Classification example
At 15:30, three comparable expiries are quoted as follows:
| Contract | Price |
|---|---|
| September | 100.00 |
| December | 103.00 |
| March | 101.50 |
Using the far-minus-near convention:
S(Sep,Dec) = 103.00 − 100.00 = +3.00The first segment is in contango. The next segment is:
S(Dec,Mar) = 101.50 − 103.00 = −1.50and is in backwardation. The precise description is “contango from September to December and backwardation from December to March in the 15:30 snapshot.” These numbers imply neither the next spot move nor the P&L of an investor who maintains a position.
Effect on longs, shorts and rolling
In a futures roll, a position moves from one contract to another through two transactions. For a long, on a contangoed segment the replacement contract is priced above the near contract; in backwardation it is priced below. For a short, the transactions have the opposite directions. This is the price relationship at the time of the switch, not yet the overall result.
| Segment at the roll | Long moving farther out | Short moving farther out |
|---|---|---|
| Contango | reopens at a higher nominal price | reopens the short at a higher nominal price |
| Backwardation | reopens at a lower nominal price | reopens the short at a lower nominal price |
Profit or loss comes from the entry and exit prices of each contract, the
multiplier and costs. Example: a long buys the near contract at 98 and sells it
at 100, realizing +2. At the same time, the investor buys the deferred
contract at 103 in contango; later it is sold at 106, realizing +3. Gross
result across the two legs is +5 units per contract before the multiplier,
despite contango. If the second contract is instead sold at 100, the total is
+2 − 3 = −1. The initial shape guaranteed neither outcome.
Quantity can also change to keep notional or risk constant; the legs of a calendar spread may not execute simultaneously; bid-ask, commissions, slippage and liquidity matter. The price gap alone must therefore not be booked as if it were an immediate loss or gain.
Why they do not guarantee roll yield
Roll yield depends on the index or analytical definition: selected contract, roll window and frequency, weights, any interpolation, collateral and treatment of costs. All else held constant, convergence of a high-priced contract towards a lower reference can penalize a long exposure, while convergence from a lower price can support it. But “all else held constant” is an assumption, not an outcome.
During the holding period, spot, the whole curve and individual spreads can move; the most liquid contract can change; delivery discontinuities can emerge. A short exposure reverses some signs but retains adverse-movement, margin and cost risks. A futures-linked product can also include collateral return, fees, tracking difference, leverage or resets.
CFTC and FINRA communications on products linked to commodity futures stress that results can diverge from spot price and that repeatedly renewing contracts is one component, not a mechanical promise.
Common error — “Contango means a certain loss for the long; backwardation means a certain gain.” This shortcut ignores curve evolution, actual convergence, timing, the roll rule, collateral and costs.
Checklist before using the label
- Which two expiries am I comparing?
- Are quotes, timestamp, underlying and specifications homogeneous?
- Is the spread far minus near or the reverse?
- Is the shape local, uniform or mixed along the curve?
- Am I confusing a futures comparison with basis against spot?
- Is an expiry near delivery or with low liquidity distorting the segment?
- For a roll, which contracts, dates, quantities and execution prices am I using?
- For return, have I separated contract movement, collateral and costs?
- Is the conclusion still descriptive, or am I inventing a forecast?
Sources
- U.S. Commodity Futures Trading Commission, Futures Glossary — institutional definitions of contango, backwardation, spreads and futures terminology.
- U.S. Commodity Futures Trading Commission, Customer Advisory: Learn About Risks Before Investing in Commodity ETPs or Funds — contract rolls and divergence between futures-linked products and spot prices.
- Financial Industry Regulatory Authority, Regulatory Notice 10-51 — risk, roll yield and the behaviour of products linked to commodity futures.
- CME Group, Understanding Futures Expiration & Contract Roll — transactions required to move between expiries.
- Campbell & Company, Deconstructing Futures Returns: The Role of Roll Yield, white paper hosted by CME Group — contango, backwardation, convergence and roll return.
- U.S. Commodity Futures Trading Commission, Economic Requirements — Policy Statement on Price Differentials — grade, location, differentials and the economic structure of deliverable contracts.