Storage Costs and the Theory of Convenience Yield

Convenience yield is the benefit of holding a physical commodity directly, and it can push a futures curve into backwardation.

Convenience yield is the benefit a holder of a physical commodity gets from having it in hand rather than a claim on future delivery, a benefit that shows up in futures pricing as a subtraction from the cost of carry and can push a futures curve into backwardation even when storage and financing costs are strictly positive. The theory matters because it explains curve shapes that a plain cost of carry model, storage plus financing with nothing subtracted, cannot.

The cost of carry model states that a futures price for delivery at some future date should equal the spot price plus the cost of storing and financing the commodity until that date, minus the convenience yield earned by holding it physically. If storage and financing cost $3 a unit over the period and convenience yield is $1, the futures price sits $2 above spot, a small contango. If convenience yield rises to $4, exceeding storage and financing costs, the futures price falls below spot, and the curve moves into backwardation.

This single equation, once the terms are understood individually, explains most of the shape variation seen across commodity futures curves, and it is one of the more commonly tested pricing relationships for a commodities-focused interview.

A refinery holding physical crude oil inventory can keep running if a supplier delivery is delayed, can respond to an unexpected spike in demand for refined products without waiting for a futures contract to settle, and avoids the risk of a supply disruption leaving it without feedstock. None of that optionality shows up on a balance sheet as an explicit cash flow, but it is real value, and convenience yield is the market's way of pricing it into the relationship between spot and futures prices.

Convenience yield rises when inventories are low relative to typical demand, because the marginal barrel of physical supply becomes more valuable precisely when there is less of it, and it falls toward zero, or becomes economically irrelevant, when inventories are abundant and a supply disruption is unlikely to bind on anyone's operations.