Contango, Backwardation and the Price of Storage

Commodity prices for delivery next month and next year are rarely the same. The shape of that curve is largely a statement about storage.

Holding a commodity costs money

Owning physical material means paying for a tank, warehouse or silo, insuring it, and tying up capital that could be earning elsewhere.

Those costs accumulate with time. Holding a tonne for a year costs substantially more than holding it for a month.

A forward price therefore starts from the spot price plus what it would cost to carry the material to that future date.

Contango is the normal shape

When later deliveries cost more than nearer ones, the market is in contango, and the spread roughly covers storage, insurance and financing.

If the spread grows wider than those costs, buying now and selling forward becomes profitable, and traders doing so bid up the spot price until the gap closes.

This arbitrage is what anchors the curve to physical reality, and it works only while storage capacity is available to those who want it.

Backwardation says the market wants it now

Sometimes the near price sits above the distant one. Paying more for immediate delivery than for the same material later is only rational if having it now has value.

That value is the convenience of holding physical stock: a refinery or mill that runs out stops, and no forward contract restarts it.

Backwardation is therefore a scarcity signal. It usually appears when inventories are low relative to consumption and buyers are competing for prompt cargoes.

Storage limits break the arithmetic

The link between the curve and carrying costs assumes storage can be found. When tanks and warehouses fill, that assumption fails.

With nowhere to put additional material, the spot price can fall far below what carrying costs alone would suggest, because holding is not an option at any price.

The same constraint works in reverse for commodities that are difficult or impossible to store, where the curve carries much less information about carrying cost.

What producers and consumers read from it

The curve shape affects behaviour directly. A steep contango encourages stockpiling and financing deals; backwardation discourages holding inventory at all.

Producers use forward prices to decide whether to accelerate or defer output, and consumers use them to decide how far ahead to cover their needs.

Because the shape shifts with inventories, weather and disruption, it is read as a running commentary on physical tightness rather than as a forecast.