Why Are Petrol Prices Stuck When Oil Costs Fall? The CMA Wants Answers

Fill up today and check the pump price. Then think back to the news headlines from a few weeks ago about crude oil dropping, wholesale fuel costs easing, and analysts predicting relief for drivers. Did the number on the forecourt board actually move? For a lot of motorists, the honest answer is: not much, and not quickly.

That gap between what happens in the wholesale fuel market and what actually lands on the pump price is now firmly in the sights of the Competition and Markets Authority (CMA). According to Auto Express, the watchdog is examining why retailers have been slow to pass on wholesale price reductions to drivers, with a more detailed report expected in the autumn. It's a story that sounds small on the surface, a few pence here or there, but it touches on some of the most important consumer protection questions in UK motoring.

What's Actually Happening

The CMA isn't simply speculating. It has an established monitoring function for road fuel prices, built on the back of its 2023 road fuel market study, and it continues to track how retail prices respond when wholesale costs shift. What this latest scrutiny reflects is a familiar and well documented pattern in fuel retailing: when wholesale costs rise, pump prices tend to follow almost immediately. When wholesale costs fall, the retail price often takes noticeably longer to catch up, if it moves at all in the short term.

This isn't a new phenomenon and it isn't unique to the UK. Economists have a name for it: "rocket and feather" pricing, where prices shoot up like a rocket when costs increase but drift down like a feather when costs fall. The CMA's interest is in establishing whether this pattern reflects genuine cost lags, timing quirks in how retailers buy and store fuel, or whether it points to something closer to weak competitive pressure allowing retailers to sit on their margins for longer than they should.

The promise of a further, more detailed report in the autumn suggests this isn't a quick soundbite of an investigation. It implies the CMA is gathering data over a meaningful period, comparing wholesale price movements against retail responses across different types of forecourt, supermarket-owned, branded, and independent, to build an evidenced picture rather than relying on anecdote.

Why This Matters Beyond the Pump

It's tempting to see fuel pricing as background noise, but for millions of households it's one of the largest and most frequent transactions they make. Fuel duty, VAT, and pump prices together make petrol and diesel among the most politically sensitive commodities in the country, and pricing behaviour that even looks unfair tends to generate real anger.

There's important context here. The CMA's 2023 road fuel market study found that fuel retailer margins, the gap between what retailers pay wholesale and what they charge at the pump, had grown compared with historical averages. That study also found that competition between fuel retailers, particularly supermarkets, had weakened over time in a way that reduced the pressure to offer the sharpest possible prices. Supermarkets had traditionally undercut other retailers to drive footfall into their stores, but the study suggested that dynamic had softened.

That earlier study led to a significant recommendation: a statutory, real-time fuel price transparency scheme, now generally referred to as the fuel finder scheme, requiring fuel retailers to report their prices so that comparison services and, eventually, satnav and mapping apps could show drivers live, accurate pricing at nearby stations. The idea is simple. If drivers can see exactly what every local station is charging in real time, then poor value forecourts have nowhere to hide, and competitive pressure increases naturally.

The current scrutiny of slow price pass-through sits on top of that earlier work. It suggests the CMA isn't satisfied that the problem has gone away simply because transparency measures are being rolled out. If retailers are still dragging their feet on cutting prices when wholesale costs fall, transparency alone may not be enough.

The Legal and Regulatory Angle

It's worth understanding what powers the CMA actually has here, because "investigation" can mean different things in competition law.

The CMA's road fuel work began as a market study under the Enterprise Act 2002. A market study allows the CMA to examine how a market is functioning without needing to prove that any individual company has broken competition law. It can result in recommendations to government, calls for voluntary industry action, or, if the evidence justifies it, a referral for a full market investigation, a much more intensive and formal process carried out by an independent CMA panel with the power to impose legally binding remedies on the sector.

So far, the fuel market work has stayed largely in study and monitoring territory rather than escalating to a full market investigation, but continued evidence of retailers failing to pass through savings could increase pressure for a tougher response. The statutory fuel finder scheme itself came from powers created under the Digital Markets, Competition and Consumers Act 2024, which strengthened the CMA's ability to impose transparency requirements on markets where information asymmetry, drivers not being able to see or compare prices easily, was identified as part of the problem.

It's also worth noting that pricing decisions themselves, setting a margin, choosing not to cut prices quickly, are not automatically illegal. Retailers are generally free to price their own products as they see fit under UK law. What competition law targets is collusion between competitors, abuse of a dominant market position, or systemic market failures that harm consumers, not simply the fact that a business chose to keep more margin for longer. That distinction matters for understanding what any autumn report is likely to recommend. It will almost certainly focus on structural fixes, more transparency, better data, easier price comparison, rather than accusing individual fuel retailers of wrongdoing.

What Drivers Should Know

While the regulatory process plays out, there are practical things drivers can do to make sure they aren't the ones absorbing a slow pass-through of savings.

• Use live fuel price comparison tools. As the statutory fuel finder scheme develops, price comparison apps and satnav integrations should become more reliable and comprehensive, giving a genuine local snapshot rather than relying on memory or habit.
• Don't assume your usual station is cheapest. Loyalty to a particular supermarket or brand can cost money. Prices can vary meaningfully between stations just a few miles apart, particularly between supermarket forecourts and independents.
• Watch the wholesale price story, but don't expect instant pump reflection. If you read that oil prices have dropped, it's reasonable to expect pump prices to ease over coming days or weeks, not necessarily overnight.
• Consider fill-up timing where practical. Prices can and do fluctuate across a region and over time, so filling up strategically rather than always topping up at the nearest station can add up over a year of driving.
• Keep an eye on official CMA updates. The CMA publishes findings and recommendations publicly, and its ongoing fuel market monitoring is a useful barometer for whether pricing behaviour is genuinely improving.

None of this is a substitute for the structural fix the CMA is pushing for. Individual drivers shopping around can only do so much when the underlying transparency and competitive pressure in the market itself is weak. But being an informed customer, rather than a passive one, remains the most immediate lever available.

Looking Ahead

The promised autumn report will be the next real test of whether this scrutiny leads anywhere meaningful. If the CMA's data confirms that retailers are systematically slower to cut prices than to raise them, expect renewed pressure for either stronger transparency obligations, tighter monitoring, or in a more serious scenario, a formal market investigation reference with binding remedies attached.

For now, the message for drivers is one of cautious vigilance rather than outrage. Fuel pricing has always lagged behind headline oil market movements to some degree, but the CMA's continued interest signals that regulators are no longer willing to treat a slow trickle-down of savings as simply the cost of doing business. Whether that translates into genuinely lower prices at the pump by the time autumn's report lands remains to be seen, but it's a space well worth watching for anyone who fills up regularly.