Commodity roll yield is the component of a commodity futures strategy's return attributed to maintaining exposure as contracts age and are replaced, measured under a stated benchmark and sizing convention. It helps explain why holding a futures-based commodity investment can produce a different return from the change in the commodity spot price.
The crucial distinction is between replacing a contract and earning or losing money while holding it. A price difference between two delivery months changes the terms of the new exposure. It does not, by itself, put that difference into the investor's cash account.
A roll is two trades, with two histories
A trader rolls a long futures contract by selling the contract already held and buying a later-dated contract. CME describes the roll as offsetting the current position and establishing a new one. The old contract's P&L depends on its own entry price; the new contract starts at the prevailing futures price. CME's contract-roll explanation describes this sequence.
Consider fictional futures on one specified commodity grade and location. Each contract represents 100 commodity units; the trader holds one long contract throughout. Prices below are USD per unit. There are no trading costs or interest, both contracts are closed before delivery, and funding requirements are outside the calculation.
| Event | Price | Cumulative trading P&L for that contract |
|---|---|---|
| Enter the old, nearer contract | 98 | USD 0 at entry |
| Close the old contract at the roll | 100 | |
| Enter the later contract at the same roll instant | 105 | USD 0 at entry |
| Later close that contract, assuming its price falls to 100 | 100 |
At the roll, the later contract is quoted 5 USD per unit above the nearer one: this pair is in contango. The trader does not pay USD 10,500 to buy physical inventory or incur a separate USD 500 trading loss when entering the new future. A newly entered future at its prevailing price has zero initial derivative value. Initial margin can still require a cash deposit; that deposit is collateral, not the contract's purchase price or a trading loss.
The later USD 500 loss arises from the assumed subsequent move from 105 to 100 in the same contract. If that contract instead stays at 105, its holding P&L is zero. If it rises to 110, its holding P&L is positive USD 500. None of these paths is determined by the curve observed at the roll. The same caution applies to a backwardated pair: a lower replacement quote does not guarantee a later gain.
Original synthetic two-contract ledger. The near and far quotes coexist at the roll; the later far-contract price of 100 is an assumed outcome. P&L amounts sum variation settlements with zero costs and interest; margin deposits, funding and delivery are excluded.
The cumulative trading result across both holding periods is . With daily variation margin, the gains and losses occur through settlement cashflows during the holding periods. Do not add the endpoint P&L again as a new payment when closing. CME's mark-to-market explanation explains the daily settlement mechanism.
Why contango is called a roll headwind
Imagine that, as each contract approaches expiry, it repeatedly falls toward an unchanged delivery-market price. Replacing a nearer contract with a higher-priced deferred contract then exposes the long investor to that assumed decline again. This is the intuition behind negative roll yield in contango. Reverse the stipulated convergence pattern and the roll component can be positive in backwardation.
Convergence is toward the relevant price at settlement, under the contract's delivery or cash-settlement terms. It does not lock in convergence toward today's spot price. Demand shocks, inventory changes, seasonality and movements of the whole curve can alter the realised result. The Commodities lesson, available with a free signed-in account, explains the physical specifications, storage and convenience yield behind these differences.
Quantity and denominator matter
Our ledger holds 100 units fixed. The quoted notional exposure changes from just before the roll to just after it. These notionals measure exposure; neither is the future's initial value.
A strategy keeping USD 10,000 of quoted notional fixed at the roll would instead choose
Its subsequent loss on the stipulated move to 100 would be . That comparison allows fractional exposure for teaching; actual contract sizes can prevent an exact notional match. It holds notional constant only when replacing the contract, without continuous rebalancing afterward.
Even the shorthand percentage “roll gap” needs a definition: , whereas . They use different denominators. Neither ratio is an immediate cash loss. For the fixed-quantity new holding period, is trading P&L divided by its entry notional, not a return on the margin deposit.
Read the return series before attributing it
For a commodity index, the selected contracts, roll dates, weights and reinvestment rules determine the measured futures return. A spot-price series measures something different. An analyst can define an arithmetic roll-attribution residual as the futures strategy's excess return minus a specified spot-price return; that is a chosen decomposition, not a separate cash distribution. The benchmark, denominator, period and arithmetic versus compounded convention must accompany the number.
In S&P's terminology, an excess return commodity index tracks the futures portfolio, while total return additionally includes the methodology's hypothetical collateral interest. The current S&P GSCI methodology makes that distinction. Its supporting index mathematics calculates contract daily returns using previously held weights and the contracts' new prices. Switching the quoted contract alone should not be counted as a holding-period price move.
A real fund also has fees, execution costs and its own collateral arrangements. Collateral yield is separate from futures trading P&L; it is not automatically interest on the margin deposit at a freely chosen rate. A useful roll-yield comparison therefore starts with the actual position ledger and the product's return methodology.
Sources
- CME Group — Understanding Futures Expiration & Contract Roll.
- CME Group — Mark-to-Market.
- S&P Dow Jones Indices — S&P GSCI Methodology, August 2026, p. 12.
- S&P Dow Jones Indices — Commodity Index Mathematics Methodology, August 2025, pp. 5–6 and 21–22.
- John C. Hull, Options, Futures, and Other Derivatives, 9th Global Edition, Pearson 2018, §3.6, pp. 90–91: sequential contracts in a rolling hedge.