Why Strait of Hormuz Attacks Move Oil Prices

Attacks near the Strait of Hormuz move global oil prices because the strait is the world’s most important oil chokepoint, through which roughly one-fifth of global petroleum consumption passes daily. Even the threat of disruption there triggers a risk premium in oil futures, as traders price in the possibility of supply being cut off. This article explains the strait’s role, the mechanics of price moves, and what it means for consumers and markets.

Formula

The calculator above works out the average speed of a tanker transiting the Strait of Hormuz. The formula is:

Speed (km/h) = Distance (km) / (Time (min) / 60)

Where:

• Distance (d) – the length of the transit through the strait in kilometers (the strait is about 33 km wide at its narrowest point).
• Time (t) – the time taken to cross, in minutes.
• Speed – the average speed in kilometers per hour.

The second output converts that speed to meters per second for comparison with other measurements.

Worked Example

Using the default values: a tanker takes 30 minutes to cross the 33 km wide strait.

Step 1: Convert minutes to hours: 30 / 60 = 0.5 hours.

Step 2: Divide distance by time: 33 / 0.5 = 66 km/h.

Step 3: Convert to m/s: 66 * 1000 / 3600 = 18.33 m/s.

The calculator shows an average speed of 66 km/h (18.33 m/s).

Why the Strait of Hormuz Matters

The Strait of Hormuz is a narrow waterway between Iran and Oman, connecting the Persian Gulf with the Gulf of Oman and the open ocean. It is the only sea route for most of the oil and gas produced by Saudi Arabia, Iraq, the UAE, Kuwait, and Qatar. According to the U.S. Energy Information Administration, about 20 million barrels of oil and petroleum products pass through the strait each day, which is roughly 21% of global petroleum consumption and about 20% of global LNG trade.

Because there is no practical alternative pipeline for most of this volume, the strait is a classic chokepoint. If it were closed, even temporarily, tankers would have to reroute around the Arabian Peninsula, adding thousands of kilometers and weeks of transit time. That physical constraint is what makes the strait so sensitive to geopolitical events.

How Attacks Affect Oil Prices

Oil prices are set on global futures markets, where traders buy and sell contracts for future delivery. Prices reflect not just current supply and demand, but expectations about future supply. When an attack occurs near the strait, traders immediately reassess the risk of supply disruption. That reassessment is called a risk premium – the extra amount buyers are willing to pay to hedge against potential shortages.

For example, after a 2019 attack on tankers near the strait, Brent crude jumped about 4% in one day. Even if the actual supply loss was small, the market priced in the possibility of a larger disruption. The effect is magnified because oil is traded globally – a threat to 20% of supply affects every buyer, not just those in the region.

What Moves the Market: Real vs. Perceived Risk

Not all attacks have the same impact. The market distinguishes between:

• Actual supply loss – if tankers are damaged or sunk, that oil never reaches market. The price impact is direct and immediate.
• Perceived risk – even if no oil is lost, the attack signals that future shipments may be at risk. This raises insurance rates for tankers, which adds to shipping costs, and prompts some buyers to stockpile inventories.
• Retaliation potential – attacks often lead to military responses, which could escalate and close the strait entirely. The market prices in that tail risk.

The key is that oil prices are forward-looking. A single attack can shift the entire supply curve for months, even if the physical damage is repaired quickly.

Historical Examples and Market Reactions

Several incidents illustrate the pattern:

• 1980s Tanker War – during the Iran-Iraq war, attacks on tankers in the Persian Gulf led to a sustained risk premium and higher insurance costs, but the strait remained open.
• 2019 Tanker Attacks – two tankers were attacked near the strait in June 2019. Prices rose 4% that day, then settled as supply was unaffected.
• 2020 U.S.-Iran Tensions – after a U.S. drone strike killed a senior Iranian commander, oil briefly spiked above $70 a barrel before falling back.
• 2023-2024 Red Sea Attacks – while not the strait, attacks on shipping in the Red Sea forced tankers to reroute around Africa, adding 10-15 days to voyages and raising freight rates, which indirectly lifted oil prices.

In each case, the price move was larger when the attack raised the probability of a full closure, not just a one-off incident.

How to Read Oil Price Movements

When you see a headline about an attack near the strait, the price change you see is the market’s best guess at the probability of a supply disruption. A 2% move suggests traders see a small but real risk. A 10% move suggests a serious threat.

For consumers, the effect shows up at the pump with a lag of a few days to a few weeks, depending on how much of the price is crude versus taxes and refining costs. In the U.S., crude oil typically accounts for about 50-60% of the price of gasoline. So a 5% rise in crude might translate to a 2-3% rise at the pump.

Common Misconceptions

Misconception: “The strait is closed, so prices will skyrocket.� In reality, the strait has never been fully closed for more than a few days. Even during the Iran-Iraq war, it remained partially open. A full closure is extremely unlikely because Iran itself relies on the strait for its own exports, and any closure would invite international naval intervention.

Misconception: “Attacks always cause a spike.� Not always. If the attack is seen as isolated and the market has spare capacity, prices may barely move. The market only reacts strongly when the attack changes the perceived balance of supply and demand.

Alternatives to the Strait

There are limited alternatives to the strait for Persian Gulf oil:

• Saudi East-West Pipeline – can carry about 5 million barrels per day from the Persian Gulf to the Red Sea, but it’s not enough to replace the 20 million that transit the strait.
• UAE’s Fujairah Pipeline – bypasses the strait for some UAE crude, but capacity is limited.
• Rerouting around Africa – adds 30-40 days to transit time and significantly increases costs.

Because these alternatives are insufficient, the strait remains indispensable, and any threat to it will continue to affect global oil prices.

Frequently Asked Questions

Q: How much oil passes through the Strait of Hormuz daily?
About 20 million barrels of oil and petroleum products, which is roughly 21% of global consumption. It also carries about 20% of global LNG.

Q: Why do oil prices rise even if no oil is actually lost?
Because oil prices are set on futures markets that reflect expectations. An attack signals that future supply may be at risk, so traders add a risk premium to hedge against potential shortages.

Q: Can the strait be closed completely?
Technically, Iran could mine the strait or use anti-ship missiles, but the U.S. Navy and other forces would likely clear them. A full closure is unlikely because it would hurt Iran’s own exports and provoke a major military response.

Q: How long does it take for oil price changes to reach consumers?
Typically a few days to a few weeks, depending on how much of the final price is crude oil versus taxes, refining, and distribution costs. In the U.S., crude is about 50-60% of the pump price.

Q: What is the “risk premium� in oil prices?
It’s the extra amount traders are willing to pay for oil due to the risk of supply disruption. It can be as low as a few cents or as high as several dollars per barrel, depending on the perceived threat.

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in t | Time to cross strait | min | 30 | 0
in d | Distance through strait | km | 33 | 0
out speed | Average speed | km/h | d / (t / 60) | 2
out speed_ms | Speed in m/s | m/s | (d * 1000) / (t * 60) | 2