The rate comes out of a formula. Kazakhstan levies the duty as the recent market price times a coefficient of one, so the $76-a-barrel average it logged for KEBCO and Brent between 20 June and 20 July pulls the August duty down 23%.
Timing carries more weight than the mechanics. The CPC pipeline, which moves more than 80% of Kazakh crude, stopped taking oil on 21 July after drone strikes on tankers at its Black Sea terminal, and resumed loading only on 27 July. First-half output had already fallen 8.4% to 45.7 million tonnes, and the full-year target has slipped toward 96 to 98 million tonnes.
A lighter duty on fewer barrels is a smaller cut of a smaller pie, and the budget feels both edges.
For a budget that leans on oil rents, the lower duty marks the squeeze the tanker war has put on the north-bound route. Exporters pay less per tonne because they earn less per barrel, and there are fewer tonnes to load.