Roll Yield: How Contango and Backwardation Drive Returns

Key Takeaways

• Roll yield equals the percentage difference between the expiring contract price and the next contract price; a front-month contract 2.5% above the next month produces negative roll yield of minus 2.5% per roll.
• A crude oil fund rolling monthly in a 1% contango loses roughly 12% per year to roll costs even if spot oil stays flat.
• Investors routinely expect a commodity ETF to track spot prices, but long-only funds hold futures, in persistent contango the tracking gap can reach double digits annually.
• Some commodity indexes use roll-select strategies that rotate into expiration months with the most favorable (least negative) roll yield to reduce contango drag.

What It Is

A futures trader who wants continuous exposure to an underlying cannot just hold a single contract forever. Every contract expires. To maintain the position, the trader sells the expiring contract and buys a later-dated one, a process called rolling.

The CME Group research on roll yield defines it as "the difference in return between a futures contract and the underlying spot price." Roll yield isolates the effect of moving from one expiration to the next, separate from any spot price change. For commodities, roll yield can also include non-cash costs and benefits like the convenience yield of holding the physical material.

The Intuition

Imagine the spot price of oil is flat at 80 dollars for an entire year. A long-only commodity fund that holds front-month crude futures still has to roll every month. If each next-month contract costs more than the current one (contango), every roll sells low and buys high. Even though the spot has not moved, the fund bleeds value on every roll.

Flip the curve. If each next-month contract is cheaper than the current one (backwardation), every roll sells high and buys low. The fund earns a positive carry just by rolling forward. Spot again has not moved, but the position earns money.

This is why roll yield can dominate commodity fund returns over multi-year periods. A flat spot can produce deep losses in contango or steady gains in backwardation, depending entirely on the shape of the futures curve.

How It Works

For a simple front-month roll, approximate roll yield per roll as the percentage difference between the expiring contract price and the new contract price:

roll yield per roll ~ (F_near - F_next) / F_near

Where:

F_near  = price of the expiring (near) contract
F_next  = price of the next-out contract being rolled into

A positive number here means backwardation (you are selling the expiring contract for more than you pay for the next one, a positive carry). A negative number means contango.

Annualized roll yield is roughly the per-roll figure times the number of rolls per year. A commodity fund rolling monthly in a curve where each next-month contract is about 1 percent higher than the expiring one would lose roughly 12 percent a year to rolls, all else equal. In backwardation of the same magnitude, it would gain roughly 12 percent.

Real curves are not flat between expirations. Exchanges list multiple months with different spreads, and fund strategies differ in which month they roll into and how they stagger the trade. Some "roll-select" commodity indexes choose the expiration that maximizes roll yield rather than mechanically rolling the front month, specifically to mitigate contango bleed.

Worked Example

A real-world case study is passive crude oil exposure through front-month rolling funds. The CME Group note on crude oil futures versus ETFs points out that performance of commodity ETFs like USO deviates from WTI spot prices "due to roll yield, transaction costs and management fees."

Suppose WTI spot is 80 dollars per barrel. The front-month futures contract is at 80 and the next month is at 82. A front-month fund rolls monthly:

sell front       = $80
buy next month   = $82
roll return      = (80 - 82) / 80 = -2.5% per roll

If the curve stays in that shape for twelve months and spot does not move, the fund loses roughly 2.5 percent every month on the roll, compounding to about minus 26 percent over the year. Even if spot oil closes the year flat at 80, the fund's NAV has been ground lower by the rolling process.

Now flip the curve. Front month at 80, next month at 78.

sell front       = $80
buy next month   = $78
roll return      = (80 - 78) / 80 = +2.5% per roll

In this backwardated market the fund earns about 2.5 percent per roll on top of any spot moves. This is the mechanism that lets some commodity carry strategies earn a positive return even when spot is flat or modestly declining.

Common Mistakes

1. Expecting a commodity ETF to track spot. Long-only commodity funds hold futures, not the physical commodity. In persistent contango they can underperform spot by double-digit percentages a year. The tracking gap is roll yield, not mismanagement.

2. Confusing roll yield with carry on financial futures. On interest-rate and equity-index futures, the relationship between near and next contracts is driven by the risk-free rate and dividends, not convenience yield. Rolling those contracts has a different economic interpretation.

3. Ignoring how far out you roll. Rolling front-to-next produces a different yield than rolling front-to-three-month-out. Strategy choices about where on the curve to roll are a major design decision for commodity index investors.

4. Assuming historical roll yield predicts future roll yield. Curve shapes shift. A commodity that spent years in backwardation can flip into contango after a supply increase, turning a long-standing tailwind into a headwind.

Frequently Asked Questions

Q: What is roll yield in simple terms? Roll yield is the gain or loss that comes from selling an expiring futures contract and buying a later-dated one to maintain the position. If you sell at a higher price and buy at a lower price (backwardation), you earn roll yield. If you sell low and buy high (contango), you pay it.

Q: How does roll yield affect investment decisions? Roll yield is a hidden performance drag or tailwind in any futures-based strategy. An investor who ignores it will be confused when a commodity ETF trails spot price by 10 to 20 percent in a year, even though the commodity itself did not move much. Roll yield must be modeled before any futures-based allocation is made.

Q: What is a real-world example of roll yield? The USO crude oil ETF famously suffered deep roll-yield losses during the 2015-2016 crude collapse, when the market was in steep contango. Each month the fund sold cheaper near-month contracts and bought more expensive next-month ones, locking in losses even as WTI spot eventually stabilized.

Q: How can investors reduce the impact of negative roll yield? Use roll-select commodity indexes that choose the expiration month with the most favorable roll yield rather than mechanically rolling front-to-next. Alternatively, gain commodity exposure through equity of commodity producers, which avoids futures curves entirely.

Q: How is roll yield different from spot return in a commodity investment? Spot return is the price change of the physical commodity. Roll yield is a separate, independent return component that arises only from holding futures. The total return of a futures strategy equals spot return plus roll yield plus any collateral return, three distinct sources that need to be tracked separately.

Sources

1. CME Group. "Deconstructing Futures Returns: The Role of Roll Yield." https://www.cmegroup.com/education/files/deconstructing-futures-returns-the-role-of-roll-yield.pdf
2. CME Group. "Crude Oil: Futures versus ETFs." https://www.cmegroup.com/education/courses/introduction-to-energy/introduction-to-crude-oil/crude-oil-futures-vs-etfs.html
3. CME Group. "What is Contango and Backwardation." https://www.cmegroup.com/education/courses/introduction-to-ferrous-metals/what-is-contango-and-backwardation.html

Disclaimer

This article is educational content only and is not financial advice. Nothing here is a recommendation to buy, sell, or hold any security. Consult a licensed advisor before making investment decisions.