A peak season surcharge, or PSS, is a temporary per-container surcharge carriers add on top of base freight during periods of high demand, classically the pre-holiday shipping build-up on major east-west trades. It is announced with an effective date and lifted, in principle, when demand normalises.
PSS exists because demand for vessel space is seasonal while capacity is fixed in the short run. When bookings exceed slots, carriers add PSS to tariff and spot cargo; contracts may cap, exclude, or explicitly allow it, which makes the contract wording worth reading before peak quarter.
A PSS is distinct from a GRI: a GRI raises the base rate itself, while PSS is an additional line item layered on during the peak window. In practice carriers use both levers together when space is tight.
The conditions that justify a PSS are visible operationally: full vessels, rolled containers, and blank sailings to manage capacity. If your tracked shipments start slipping to later vessels on a lane, that is the same tightness a PSS prices. Watching per-carrier performance in TrackingMCP, for example Evergreen or COSCO, shows whether peak pressure is real on your corridor.
A peak season surcharge, or PSS, is a temporary per-container surcharge carriers add on top of base freight during periods of high demand, classically the pre-holiday shipping build-up on major east-west trades. It is announced with an effective date and lifted, in principle, when demand normalises.
On east-west trades the classic peak runs from late summer into autumn ahead of year-end retail, with a smaller pre-Lunar-New-Year peak. Actual timing shifts year to year with demand and inventory cycles.
Contract shippers often negotiate PSS caps or exclusions at tender time. Spot shippers largely face the announced level, moderated only by competition between carriers for the booking.
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