Three Clocks on a Tax Date: Cost, Posting, and the Measurement of Tax Pass- Through

Temporary fuel-tax cuts are judged by how much of them reaches the pump, and the judge is the change in price around the date in the statute. We show that this date is one of three clocks. The tax is fixed when fuel leaves the warehouse, so a station’s paid cost changes with its next delivery; its price changes when it posts. We read the three clocks in every price change at German fuel stations around two cuts and their reversals, in 2022 and 2026. Net of the usual overnight change, more than half of the statutory amount is posted within four hours of midnight in three events, although at midnight no station holds fuel taxed at the new rate: the price follows the next liter, not the liter in the tank. Where a rule confines increases to noon, the restoration was posted the afternoon before. Prices had moved before every event, by a quarter to a half of the statutory amount, after a German announcement and under German posting rules, and no control country removes that movement, so it enters any estimate through the reference period. Against a window of earlier days the measured response to the 2026 cut is 47 percent; against the previous day it is 87 percent, and whether a restoration is passed through more than its cut changes sign in both years. A statute-dated estimate should report its reference period and, where timestamps exist, the share posted at the legal instant.