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Contango and backwardation

Contango and Storage Costs

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Contango and Storage Costs

The contango curve exists fundamentally because holding commodities carries real, measurable costs. Storage costs, financing costs, and insurance are not theoretical—they are concrete expenses that must be paid by whoever holds physical inventory or owns a long futures position. The size and shape of contango reflect these accumulating carrying costs. Understanding the components of carrying costs is essential for understanding why contango exists, how deep it might be, and when it might break down or intensify.

The Three Components of Carrying Costs​

Carrying costs consist of three distinct elements: physical storage, financing, and insurance. Each varies by commodity type, market conditions, and the specific facilities and arrangements used.

Physical Storage is the most visible component. Crude oil requires tank storage with capacity limitations, security, maintenance, and monitoring. Grain requires elevators or warehouses with temperature and moisture control. Precious metals require secure vaults with climate control. These facilities are expensive to build and operate. A large crude oil storage facility might cost $50–100 million to construct and incur annual operating costs of 5–10% of replacement value.

The per-unit cost of storage depends on the scale and type of facility. Crude oil storage costs roughly $0.10–$0.30 per barrel per month depending on location, facility size, and utilization rates. An efficient, high-volume facility might cost $0.08 per barrel monthly; a small or remote facility might cost $0.40. Wheat storage costs roughly $0.01–$0.03 per bushel monthly. Gold storage in professional vaults costs roughly 0.2–0.5% annually, or $2–5 per ounce on a $1,000 price.

Financing costs are the interest expense of funding inventory. If a trader buys crude oil at $75 per barrel and finances that purchase at 5% annual interest, the monthly financing cost is roughly $0.31 per barrel ($75 × 0.05 ÷ 12). This cost rises or falls with interest rates and with the spot price of the commodity. In periods of high interest rates or high commodity prices, financing becomes more expensive. In periods of low rates or low prices, financing is cheaper.

Insurance covers risks of loss, damage, or theft while commodity inventory is held. Insurance typically costs 0.5–2% annually depending on the commodity, facility, and risk profile. Oil stored in a U.S. Gulf Coast facility with established insurance markets might cost 0.5% annually; oil stored in a remote or geopolitically risky location might cost 2–3% or more.

The Mathematical Relationship​

The relationship between carrying costs and contango can be expressed simply. If monthly carrying costs total $0.50 per barrel (storage of $0.10, financing of $0.31, and insurance of $0.09), the contango between consecutive months should approximate $0.50 per barrel.

Consider a specific example with crude oil:

Current spot price:           $75.00 per barrel
Current storage cost:         $0.10 per barrel per month
Financing cost (5% annual):   $0.31 per barrel per month
Insurance cost:               $0.09 per barrel per month
Total monthly carrying cost:  $0.50 per barrel

Implied price structure:
January futures:   $75.00
February futures:  $75.50 (January + $0.50 carrying cost)
March futures:     $76.00 (February + $0.50 carrying cost)
April futures:     $76.50 (March + $0.50 carrying cost)

This simple model underlies commodity futures pricing. In perfectly efficient markets with no supply or demand shocks, contango should reflect exactly the carrying costs. Traders continuously calibrate this relationship through arbitrage—buying spot or nearby contracts, storing the commodity, and selling far-term contracts for a profit equal to carrying costs.

How Interest Rates Affect Contango Depth​

Interest rate changes directly affect contango strength. When the Federal Reserve raises interest rates from 2% to 5%, the financing component of carrying costs increases. A crude trader financing inventory at 5% instead of 2% incurs an additional $0.23 per barrel monthly in financing costs. This additional cost flows through to the futures curve, steepening contango.

Conversely, when the Fed cuts rates aggressively, contango flattens. During the pandemic crisis in March 2020, the Federal Reserve cut rates to near zero almost overnight. Commodity contango flattened notably within weeks, though supply shocks and demand destruction also played roles.

The relationship is not perfectly linear—other factors intervene—but the directional link is strong. High-rate environments typically produce steep contango; low-rate environments produce shallow contango. This dynamic is why commodity investors care about interest rate policy. A rate hike not only affects commodity spot prices but also affects the structure of the futures curve through carrying costs.

Variation Across Commodities​

Different commodities have vastly different storage costs, leading to different contango profiles.

Crude oil exhibits substantial contango because storage costs are significant (0.10–0.30/barrel/month) and financing costs are large (commodity price × interest rate). Total monthly carrying costs often reach $0.40–$1.00 per barrel, producing 5–15% annual contango if rates and prices are elevated.

Natural gas shows variable contango. Storing natural gas requires compression and specialized facilities. Liquefied natural gas (LNG) storage is extremely expensive. However, because natural gas is gaseous, most participants use futures contracts rather than holding physical inventory. The curve reflects financing costs and storage facility costs rather than direct physical carrying costs.

Gold and silver show shallow contango despite being stored in secure vaults. Gold storage costs only 0.2–0.5% annually because the physical metal occupies little space and does not degrade. Financing costs dominate, typically 2–5% annually depending on interest rates. Total contango on gold is usually 2–5% annually, much less than crude oil's typical 5–15%.

Agricultural commodities like wheat and corn show moderate contango that varies by season. At harvest, when storage is full and carrying costs are high, contango can be steep. As the crop year progresses and stored inventory depletes, contango flattens. In the months just before the next harvest, storage is minimal and contango often reverses to mild backwardation or very shallow contango.

Contango When Storage Is Constrained​

When storage capacity becomes scarce, carrying costs spike and contango steepens dramatically. This occurred repeatedly in 2020–2021 when pandemic-driven production shutdowns coincided with demand destruction, creating gluts of crude oil with nowhere to store it. Storage facilities in the U.S. Gulf Coast and Cushing, Oklahoma filled to capacity. Contango steepened to $2–3 per barrel between monthly contracts as traders scrambled to incentivize consumption rather than accumulation.

In extreme cases, when storage is completely full and producers cannot inject more commodity, contango can spike to extreme levels. During the April 2020 crude crash, some time-spread opportunities offered $5–10 per barrel contango, compensating storage operators richly for finding temporary tank space.

This dynamic highlights a critical point: contango cannot rise infinitely. When storage is saturated and additional carrying costs exceed any economic use of the commodity, the curve inverts or the spot price crashes. The contango curve serves as a mechanism to ration storage and incentivize consumption or production reduction.

Contango and the Cost of Carry Models​

This diagram illustrates how the three cost components feed into the contango curve. The futures curve is essentially a translation of these cost components into price.

Real-World Example: Crude Oil Contango in 2019​

In early 2019, U.S. crude oil (WTI) was trading spot at roughly $57 per barrel with December 2019 contracts at $62. The $5 spread reflected approximately nine months of carrying costs, or roughly $0.55 per barrel per month. Given typical crude storage costs of $0.15/barrel/month, financing at roughly $0.25/barrel/month (assuming $57 price and 5% rates), and insurance at $0.10/barrel/month, the total carrying cost was approximately $0.50/barrel/month. The observed $5 / 9 months = $0.56 per month spread matched theoretical carrying costs nearly perfectly, demonstrating the tight relationship between physical costs and curve structure.

Why Contango Matters for Physical Producers​

For a crude producer or refiner, contango creates a favorable environment. A producer can commit to selling forward several months at prices that reflect only carrying costs, allowing long-term planning with confidence in economics. A refinery can buy crude forward at prices that represent genuine storage and financing costs rather than speculative expectations, protecting operating margins.

Without contango, or with extreme contango, physical producers face uncertainty. If the curve is inverted (backwardated), sellers face pressure to sell immediately or accept very low future prices. This creates tension between maintaining inventory for operational needs versus selling to capture spot prices.

Contango and the Limits of Arbitrage​

The tight relationship between carrying costs and contango appears obvious, yet it is not perfect. Transaction costs, market friction, and constraints on capital limit arbitrage. A trader wanting to execute a "cash and carry" trade (buy spot, store, and sell futures forward) must:

  • Have capital to finance the purchase
  • Secure storage space (increasingly difficult during capacity constraints)
  • Find counterparties and execute exchanges
  • Manage credit risk and counterparty relationships
  • Pay bid-ask spreads on both spot and futures trades

These frictions mean that actual contango may deviate from pure carrying costs by 0.5–2% without attracting aggressive arbitrage. The market tolerates some inefficiency because the arbitrage is not costless.

Key Takeaways​

Contango fundamentally reflects the accumulating cost of storing and financing commodities. These carrying costs consist of physical storage, financing at current interest rates, and insurance. The contango curve translates these costs into futures prices, with each month's contract commanding a premium over the prior month approximately equal to one month's carrying costs. Higher interest rates steepen contango; ample storage flattens it. When storage capacity becomes constrained, contango spikes as an economic signal to reduce consumption or increase supply.

External References​