Reading the oil market: price, curve, supply and data

Oil has a price everyone quotes and almost nobody reads properly. A headline says “the barrel” is at a given level. Which barrel? Brent or WTI? Spot or a future contract? The useful information is often not the level, but the spread, the curve and the direction of inventories. This guide explains oil-market mechanics from price formation to the data calendar. The 2026 Hormuz shock is the case study.

Two prices for one market

There is no single oil price. There are benchmark prices tied to qualities of crude and delivery locations.

Two dominate global discussion. Brent, from the North Sea, is a light sweet crude delivered by sea. It is the global maritime benchmark and directly or indirectly anchors a large share of internationally traded crude. WTI, West Texas Intermediate, is also light and sweet but delivered at Cushing, Oklahoma, an inland pipeline hub. It is the U.S. marker.

This geography explains why the two prices differ. The Brent-WTI spread reflects transport costs, quality differences and regional imbalances. Since 2015, Brent has usually traded $2 to $8 above WTI. During the March 2026 Hormuz stress, the spread was around $4.70; by late June, after the risk premium faded, it had fallen below $3. A spread often says more than the outright price.

Asia has another reference: Dubai/Oman, a heavier, sourer crude used for Gulf cargoes to the East. OPEC also publishes its own reference basket. Reading a quote means first asking which benchmark you are looking at.

Paper price and physical barrels

The price on screens is not the price of a barrel changing hands on a dock. It is formed first in futures markets: Brent on ICE in London, WTI on NYMEX/CME in New York. Paper volume vastly exceeds physical delivery, and that is where liquidity, hedging and speculative positioning concentrate.

Physical cargoes then price off benchmarks through differentials: a specific crude trades at “Dated Brent minus $1.20” or at a premium. The differential captures quality, sulphur, density, location, shipping and refinery demand.

This structure means price moves can reflect either physical scarcity or financial positioning. The positioning side is visible in the CFTC COT report, which breaks down futures positions by trader category.

Contango and backwardation: reading the curve

Each future maturity has its own price. Connecting them produces a futures curve. Its shape is often more informative than spot.

In backwardation, spot is above future prices. The curve slopes downward. The market is paying for immediate barrels, which usually signals tightness. Backwardation discourages storage: holding oil to sell later earns less than selling now. It is typical of supply shocks or strong demand.

In contango, spot is below future prices. The curve slopes upward. The market has immediate surplus and pays for storage. Deep contango can make it profitable to buy physical oil, store it and sell futures. The extreme case was April 20, 2020, when the front WTI contract settled around -$37 because holders could not take delivery at saturated Cushing storage.

A negative oil price was not a market joke. It was a physical storage failure expressed through a futures contract.

Supply: OPEC+, shale and spare capacity

On the supply side, three forces matter.

The first is OPEC+, the OPEC group plus non-OPEC producers led by Russia. The group manages a decisive share of global supply through quotas and voluntary cuts. In 2026 it began unwinding cuts, adding roughly 600,000 barrels per day between April and June and 188,000 more in July.

The second is U.S. shale. Shale made the United States the world’s largest producer and acts as a flexible supply response: wells start and decline quickly, so production reacts faster to price than conventional projects.

The third is spare capacity, the volume that can be brought online within roughly thirty days. It is the global cushion. In mid-2026, OPEC+ spare capacity was around 5 million barrels per day, with roughly 3 million in Saudi Arabia alone. As the group reopens supply, that cushion shrinks. A market with little spare capacity is one crisis away from a price spike.

Demand: where the barrel goes

Global oil demand is around 103 to 104 million barrels per day. It is concentrated in transport, petrochemicals and industry, with growth shifting toward Asia. China, the world’s largest crude importer, acts as a swing buyer: it can buy aggressively when oil is cheap and draw on stocks when oil is expensive.

Real-time demand is difficult to measure. That is why the IEA, OPEC and the U.S. EIA publish monthly estimates that often disagree. The IEA tends to reflect consuming-country concerns; OPEC often takes a more optimistic view of demand; the EIA provides an independent U.S. statistical view.

Reading oil means comparing all three rather than treating one report as truth.

Inventories: cushion and signal

Inventories absorb the gap between supply and demand. Commercial stocks are held by refiners and traders. Strategic petroleum reserves are held by governments. IEA members are required to hold the equivalent of 90 days of net imports.

Strategic stocks are geopolitical. China’s strategic reserve, estimated around 1.24 billion barrels in early 2026, may have become the world’s largest. The U.S. Strategic Petroleum Reserve, around 409 million barrels in spring 2026 versus a peak of 727 million in 2009, has been heavily drawn down since 2022. Filling a reserve supports demand; drawing it down suppresses prices temporarily but reduces protection against the next shock.

Weekly commercial inventories move prices. A surprise build is bearish; a surprise draw is bullish. Cushing matters especially for WTI: when Cushing fills, WTI weakens versus Brent.

The data calendar

Oil has a rich, mostly free data calendar.

API, Tuesday 16:30 ET. The American Petroleum Institute publishes a private estimate of U.S. inventories. Less authoritative, but watched as a preview.
EIA, Wednesday 10:30 ET. The Weekly Petroleum Status Report is the key short-term release: crude and product inventories, Cushing, refinery utilisation and U.S. production.
Baker Hughes, Friday 13:00 ET. The U.S. rig count is a leading indicator of shale activity.
Monthly reports. The IEA Oil Market Report, OPEC Monthly Oil Market Report and EIA Short-Term Energy Outlook each provide a different read on global supply-demand balance.

Reading oil in practice

Oil is not one number. The price level gives mood. Brent-WTI gives geography. The futures curve gives tightness or surplus. Spare capacity gives fragility. Inventories give near-term direction. Together, they say what the headline does not.

The 2026 Hormuz shock shows the system. Brent moved toward $80, with stress scenarios above $100 if the Strait remained closed, while the curve shifted into backwardation. De-escalation and OPEC+ supply then pulled the barrel toward $71 by early July. The energy shock also fed directly into U.S. inflation, as explained in the CPI guide.

Oil is one of macroeconomics’ main transmission belts.

Main sources: U.S. Energy Information Administration, Weekly Petroleum Status Report and Short-Term Energy Outlook; IEA, Oil Market Report – June 2026; RBN Energy on the Brent-WTI spread; Charles Schwab on WTI versus Brent; OilPrice on OPEC+ spare capacity; EIA on China strategic stocks and the U.S. Strategic Petroleum Reserve; CME Group on the API/EIA data calendar.