Iranian Port Blockade: Flow Analysis of Oil Market Disruption

The maritime blockade of Iran's ports begins on April 13 at 10 a.m. ET, enforced by U.S. Central Command forces. Its scope is precise: it will restrict all traffic to and from Iranian ports on the Arabian Gulf and Gulf of Oman, but will not impede freedom of navigation for vessels transiting the Strait of Hormuz to non-Iranian ports.

This move follows the collapse of high-stakes negotiations in Islamabad. The U.S. delegation, led by Vice President JD Vance, stated the talks failed because Iran refused to commit to not developing a nuclear weapon. Iran's demands reportedly included control of the strait and war reparations, leaving the fragile ceasefire uncertain.

The key shipping route has been effectively closed for weeks. Since U.S.-Israeli strikes began on February 28, the de facto closure of the Strait of Hormuz has driven Brent crude to $118 per barrel by the end of the first quarter, marking its largest quarterly price increase on record.

Price Action and Market Flow

WTI crude futures surged 8.95% to $105.21 per barrel on April 12, recouping losses after the blockade announcement. This move follows a historic rally since the conflict began, with Brent crude up from $61 per barrel to $118 per barrel. The price increase during the first quarter was the largest on an inflation-adjusted basis in data going back to 1988.

The disruption is flowing through the product markets. Gasoline prices have also rallied, with RBOB futures hitting a 1-week high. This reflects tighter product supply as refiners face higher crude input costs and potential logistical bottlenecks from the closed shipping lanes.

The market is pricing in a severe supply shock. The de facto closure of the Strait of Hormuz has driven crude prices to record quarterly highs, with the Brent-WTI spread widening to over $25 per barrel at its peak in March. This divergence highlights the regional supply crunch, as Middle Eastern flows are severed while U.S. inventories provide some price support.

Supply Constraints and Market Resilience

Energy executives at CERAWeek warned that the disruption to jet fuel, diesel, and gasoline is larger than markets understand, with shortages expected to ripple through Asia and hit Europe by April. They painted a grim picture of a supply shock that could have domino effects across the global economy.

Saudi Arabia has restored full pumping capacity, offsetting some Iranian export losses. However, attacks have reduced its production capacity by roughly 600,000 barrels per day. This partial recovery provides a crucial buffer but does not eliminate the severe regional supply crunch.

The U.S. is less exposed to a direct supply shock, as a small share of its oil imports come from the Persian Gulf. Yet it faces higher pump prices, with the average cost of a gallon of gasoline up more than 50 cents since the conflict began. In a global oil market, a shock in one region inevitably drives prices higher everywhere.