How Freight Rates Are Set, and Why They Swing So Violently

Freight rates are among the most volatile prices in the economy, capable of multiplying and collapsing within a couple of years while the volume of goods moved changes only modestly.

The explanation is not speculation. It is the shape of supply.

Capacity cannot respond quickly

A container ship is ordered years before delivery. Once built it lasts decades, and the cost of operating it is largely fixed whether it sails full or half empty.

This produces a supply curve that barely responds to price in the short run. When demand rises, no additional capacity can appear for years. When demand falls, capacity cannot be withdrawn without scrapping an asset with decades of life remaining.

Trucking has shorter lead times but the same structure: capacity is added by buying vehicles and hiring drivers, and reduced by parking equipment that still carries payments.

The utilisation threshold

Because supply is inelastic, rates depend heavily on utilisation — and the relationship is not linear.

At moderate utilisation, carriers compete for cargo and rates sit near operating cost. As utilisation approaches capacity, the dynamic inverts: shippers compete for space. Rates can multiply over a few percentage points of utilisation, because the alternative for a shipper is not a cheaper carrier but no shipment at all.

The reverse is equally sharp. Once capacity exceeds demand, carriers with high fixed costs cut price to fill ships, and rates can fall below the cost of operating.

Spot and contract

Most freight moves under annual contracts at negotiated rates, with the remainder on the spot market.

Spot rates are what get reported, because they are published and move daily. They are a leading indicator of contract rates — which reset periodically at levels informed by where spot has been.

This creates a well-known pattern: when spot rates spike, contract holders are protected temporarily but face steep increases at renewal. When spot collapses, contract shippers pay above market until they can renegotiate, and some simply default to the spot market instead — which is one reason carriers' contract books are less reliable than they appear.

Congestion tightens effective supply

Capacity is not just how many vessels exist; it is how many voyages they complete. A ship waiting outside a port is not moving cargo.

Port congestion, equipment shortages and inland bottlenecks all reduce effective capacity without changing the fleet. This is why disruptions can tighten the market far beyond what the volume of affected trade would suggest — a delay does not merely postpone one shipment, it removes capacity from the system for its duration.

The same works in reverse. When congestion clears, effective capacity increases quickly, and rates can fall faster than anyone expected.

The cycle repeats

This pattern has repeated for as long as the industry has existed, and it persists because each individual ordering decision is rational at the time it is made. Every operator sees high rates and orders; collectively they create the surplus that ends them.

Alliances and capacity discipline

Ocean carriers operate in alliances that share vessel space on major routes, allowing each to offer more frequent sailings than its own fleet would support.

This is efficient and it concentrates decision-making about capacity. When alliances withdraw sailings on a route — blank sailings — effective supply falls quickly, which supports rates in a way individual operators acting alone would struggle to achieve.

Regulators have historically granted shipping some latitude here on the grounds that the service requires coordination. Whether that latitude remains appropriate is debated periodically, particularly after periods of very high rates.

Fuel, and who bears the cost

Fuel is among the largest operating costs in freight, and its price moves independently of freight demand.

Contracts typically handle this with surcharges that pass fuel costs to shippers via a formula. This protects carriers from price swings and means a headline rate understates what a shipper pays.

Environmental regulation has added a further layer, requiring cleaner fuels or emissions accounting on certain routes. These raise costs and are generally passed through, but they also alter the relative economics of older and newer vessels — which feeds back into scrapping decisions and therefore into the capacity cycle.

For anyone budgeting freight, the practical point is that the all-in cost is the rate plus surcharges plus fees, and comparing headline rates between carriers without those is comparing incomplete numbers.

The bullwhip effect

Freight demand is more volatile than consumer demand, and the amplification is structural rather than behavioural.

A modest rise in retail sales, combined with a decision to hold slightly more inventory, produces a much larger rise in orders to suppliers — and a larger one still in shipments. When demand softens and firms work down inventory instead of reordering, shipments can fall while consumption barely changes.

This is the bullwhip effect, and it explains why freight indicators often move far more than the underlying economy. It also means freight data should be read with care as an economic signal: a sharp drop in volumes can reflect inventory adjustment rather than a collapse in demand.

For shippers

The practical implication is that freight budgets built on current rates — high or low — are usually wrong. Rates mean-revert, but slowly and with large overshoots in both directions.

Firms that manage this well tend to stagger contract renewals rather than repricing everything at once, and to treat an unusually cheap freight market as temporary rather than as a new baseline to build a supply chain around.