Spot freight represents the real-time market price for truck capacity. On any given lane on any given day, spot rates reflect the balance between available truck capacity and freight demand. When capacity is tight and demand is high, spot rates rise above contract rates. When capacity is abundant, spot rates fall below contract — sometimes significantly.
Spot markets exist alongside contract markets because the relationship between shippers and carriers cannot anticipate every shipment perfectly. Shippers have unexpected volume spikes; carriers have unexpected capacity needs. The spot market is where those imbalances get resolved.
Brokers are the primary intermediaries in the spot market. They maintain relationships with large networks of carriers and match available capacity to shippers with immediate needs. Brokers earn a margin on the difference between the carrier rate they negotiate and the rate they charge the shipper.
Load boards — digital freight marketplaces — also function as spot market mechanisms. Shippers or brokers post loads; carriers search for available loads near their trucks. The load board rate is a spot rate negotiated through the platform.
For shippers, heavy reliance on spot freight is a risk indicator. Spot markets are efficient at clearing capacity, but they are unpredictable. A shipper who must cover 30% of their volume on spot faces significant rate volatility and, during capacity crunches, potential service failures. Building and maintaining carrier relationships that result in reliable contract coverage is the primary defense against forced spot dependence.
Spot rate indices — published by freight data providers using anonymized transaction data — provide benchmarks for evaluating whether a specific spot rate is at, above, or below market.