One of the great myths of commodity futures trading is the “roll return,” which Bloomberg writes about here (bonus SWP quote–but he left out the good stuff!, so I’ll have to fill that in here). Consider the oil market, which is currently in a contango, with the November WTI future ($45.99/bbl) trading below the December ($46.52/bbl). This is supposedly bad for those with a long ETF position, or an index position that includes many commodities in contango, because when the position is “rolled” forward in a couple weeks as the November contracts moves towards expiration, the investor will sell the November contract at a lower price than he buys the December, thereby allegedly causing a loss. The investor could avoid this, supposedly, by holding inventory of the spot commodity.
The flip side of this allegedly occurs when the market is in backwardation: the expiring contract is sold at a higher price than the next deferred contract is bought, thereby supposedly allowing the investor to capture the backwardation, whereas since spot prices tend to be trending down in these conditions, holders of the spot lose.
This is wrong, for two reasons. First, it gets the accounting wrong, by starting in the middle of the investment. The profit or loss on the November crude futures position depends on the difference between the price at which the November was sold in early October and bought in early September, not the difference between the price at which the November is sold and the December is bought in early October. Similarly, in November, the P/L on the December position will be the difference between sell and buy prices for the December futures, not the difference between the prices of the December and January futures in early December. You need to compare apples to apples: the “roll return” compares apples and oranges.
On average and over time, the investor engaged in this rolling strategy earns the risk premium on oil (or the portfolio of commodities in the index). This is because the futures price is the expected spot price at expiration plus a risk premium. The rolling position receives the spot price at expiration and pays the expected spot price at the time the position is initiated, plus a risk adjustment. On average the spot price parts cancel out, leaving the risk premium.
Second, the expected change in the price of the spot commodity compensates the holder for the costs of carrying inventory, which include financing costs (very small, at present), and warehousing costs, insurance, etc. Net of these costs, the P/L on the position includes a risk premium for exposure to spot price risk, and in a well-functioning market, this will be the same as the risk premium in the corresponding future.
Moving away from commodities illustrates how the alleged difference between a rolled futures position and a spot position is largely chimerical. Consider a position in S&P 500 index futures when the interest rate is above the dividend yield. (Yes, children, that was true once upon a time!) Under this condition, the S&P futures would be in contango, and there would be an apparent roll loss when one sells the expiring contract and buying the first deferred. Similarly, comparing the futures price to the spot index at the time the future is bought, the future will be above the spot, and since at expiration the future and the spot index converge to the same value, the future will apparently underperform the investment in the underlying. But this underperformance is illusory, because it neglects to take into account the cost of carrying the cash index position (which is driven by the difference between the funding rate and the dividend yield). When buys and sells are matched appropriately, and all costs and benefits are accounted for properly, the performance of the two positions is the same.
Conversely, in the current situation using the roll return illogic, the rolled position in S&P futures will apparently outperform an investment in the cash index, because the futures market is in backwardation. But this backwardation exists because the dividend yield exceeds the rate of financing an investment in the cash index. The apparent difference in performance is explained by the fact that the futures position doesn’t capture the dividend yield. Once the cost of carrying the cash index position (which is negative, in this case) is taken into consideration, the performance of the positions is identical.
Back in 1992, Metallgesellschaft blew up precisely because the trader in charge of their oil trading convinced management that a stack-and-roll “hedging” strategy would make money in a backwardated market, because he would be consistently selling the future near expiration for a price that exceeded the next-deferred that he was buying. This “logic” was again comparing apples to oranges. By implementing that “logic” to the tune of millions of barrels, Metallgesellschaft became the charter member of the billion dollar club–it was the first firm to have lost $1 billion trading derivatives.
So don’t obsess about roll returns or try to figure out ways to invest in cash commodities when the market is in a contango/carry. Futures are far more liquid and cheaper to trade, so if you want exposure to commodity prices do it through futures directly or indirectly (e.g., through ETFs or index funds). Decide on the allocation to commodities based on the risk it adds to your portfolio and the risk premium you can earn. Don’t worry about the roll. If you decide that commodities fit in your portfolio, laissez les bon temps roullez!