Crude oil rises and the sign at the filling station changes almost immediately. Crude falls and the same sign takes weeks to follow. The asymmetry is consistent enough to have a name, and it has several causes.
Retailers price from replacement cost, not purchase cost
A station sells fuel it bought days earlier, but it must buy the next delivery at whatever the market now charges.
When wholesale prices rise, holding the old price means selling inventory that cannot be replaced at that margin. The retail price moves up quickly to protect the next purchase.
When wholesale prices fall, no such pressure exists. The station can keep the old price and widen its margin until something forces a change.
Competition provides the downward pressure, and it is slow
What eventually pushes prices down is a nearby station cutting first and taking volume.
That process depends on how many competitors sit within a driver's normal route, how visible their prices are, and how quickly they notice each other.
In areas with few stations, the downward adjustment can take considerably longer than in dense corridors where signs are visible from the road.
Refining sits between crude and the pump
Drivers buy gasoline, not crude oil, and the two prices are related rather than identical.
Refinery outages, maintenance seasons and the switch between winter and summer fuel blends all move the wholesale price independently of crude.
A fall in crude can therefore coincide with a stable or rising pump price without any station changing its behaviour.
Fixed components dilute the movement
A large share of the retail price is made up of taxes, distribution, card processing and station operating costs, none of which move with the oil market.
Because those elements are effectively fixed, a given change in crude translates into a smaller proportional change at the pump in both directions.
Fuel is also a low-margin product for most retailers, who rely on the shop inside for profit, which further weakens their incentive to cut quickly.
Drivers notice increases more than decreases
Attention is asymmetric as well. A rise is noticed immediately and discussed, while a gradual decline is absorbed without comment.
Search behaviour reflects this, since motorists shop harder for cheap fuel when prices are high and stop comparing when they are low. That reduced shopping is itself part of why the fall is slow.