Predictable Prices, Higher Margins? Early Evidence on Germany’s 12 o’clock Fuel Regulation

Following the 2026 energy crisis triggered by the Iran War, Germany implemented a regulatory reform in the
retail fuel market that fundamentally altered the timing of price adjustments. Effective 1 April 2026, the Kraft-
stoffanpassungsgesetz (KPAnG) permits petrol stations to increase prices only once per day, at noon, while
allowing unrestricted price decreases. This paper provides the first empirical evaluation of the reform. The re-
sults indicate an increase in average gasoline retail margins of 5–6 cents per liter (c/l) and no significant effect
on diesel margins. We define retail margins as the difference between retail prices net of taxes and fees and Am-
sterdam–Rotterdam–Antwerp (ARA) wholesale prices. The policy reduces intraday pricing cycles from eight
to one, thereby simplifying consumer search. Additionally, the analysis reveals heterogeneous effects across re-
gions, brand size, and time of day. We conclude that the reform was successful in increasing price transparency
but failed to reduce price levels; if anything, it had the opposite effect.
Fuel pricing in Germany and internationally has been subject to sustained regulatory scrutiny and policy de-
bates (Bundeskartellamt, 2022; Bundeswettbewerbsbehörde, 2022; Competition and Markets Authority, 2023).
The global industry is dominated by few multinational and fully vertically integrated companies. The market in
Germany is highly concentrated, with six companies accounting for 84% of sales (Assad et al., 2024). Addition-
ally, retail prices exhibit pronounced Edgeworth Cycles, characterized by sharp increases followed by gradual
declines (Maskin and Tirole, 1988). While the 2013 introduction of the Markttransparenzstelle für Kraftstoffe
(MTS-K) improved transparency by mandating near real-time price reporting, pricing dynamics continued to
intensify over time: intraday cycles rose from one to seven or eight, with stations adjusting prices more than 20
times per day prior to the 2026 reform (Bundeskartellamt, 2026). This high-frequency volatility complicated
consumers’ refueling decisions.
The German reform closely resembles the Austrian Spritpreisverordnung introduced in 2011, but omits a
key feature: in Austria, only the lower-priced half of stations is publicly reported, creating additional compet-
itive pressure for inclusion, whereas in Germany all prices are disclosed (Martin, 2024). The reform aims “to
provide more transparency and reduce short-term price spikes at the fuel pump.” (Deutscher Bundestag, 2026).
Its theoretical effects are, however, ambiguous. Restricting price increases may curb opportunistic hikes, but
could also facilitate tacit coordination by making pricing more predictable. Conversely, simplified price patterns
may enhance consumers’ ability to time purchases, strengthening demand-side discipline. Denter (2026) theo-
retically shows that the regulation may weakly raise expected average prices. Empirical evidence from Austria
is inconclusive, with no clear impact on average prices (Becker et al., 2021; Fasoula and Schweikert, 2020). In
fact, there is evidence that the regulation can even backfire for consumers (Obradovits, 2014). The effect of the
most recent German reform thus remains an open empirical question.
This paper provides the first descriptive and econometric evidence on the short-run effects of the reform.
Using station-level data from the Markttransparenzstelle für Kraftstoffe (MTS-K), covering virtually all price
changes at approximately 15,000 German petrol stations, we combine retail prices with ARA wholesale bench-
marks to construct station-level margins. An interrupted time series design over a symmetric 28-day window
around 1 April 2026 indicates an increase in gasoline margins of 5–6 cents per liter, but no significant effect for
diesel. Event-study estimates show that the effect is strongest immediately after implementation and attenuates
over time. We further compare hourly intraday price effects and find that margins are lower during the morning
hours, particularly between 4 a.m. and noon, and significantly higher from noon to midnight. This pattern is
largely driven by the design of the policy, which causes one large price increase at noon everyday.
We also show that the effect of the policy is more pronounced for smaller and independent stations, while
stations affiliated with major brands exhibit effects roughly 1 c/l lower. Regionally, the effects of the policy
are strongest in Southern Germany and weaker or absent in Eastern Germany. Intraday patterns align with the
policy design, with higher prices emerging after noon and lower prices in the morning hours. Overall, the reform
simplifies price search but raises average margins during a period of elevated energy costs.
The remainder of the paper is structured as follows. Section 2 describes the data and methodology. Section 3
presents descriptive and econometric results. Section 4 concludes.

Jung, Leona, Jacob Schildknecht, Leonard Gregor und Justus Haucap (2026), Predictable Prices, Higher Margins? Early Evidence on Germany’s 12 o’clock Fuel Regulation, Mannheim