Brent drops 9.1% on Hormuz reopening; Iran re-closes strait next day

Oil's 9.1% Hormuz relief move lasted less than a day. Brent crude settled at $90.38 on April 17 after Iran said the Strait of Hormuz was open to commercial traffic, while the S&P 500 rose 1.2% to 7,126.06 and the Dow added 868.71 points, according to AP market reporting. On April 18, Iran reversed course and said the waterway was again under strict military control.

The shift came through Iran's Khatam al-Anbiya Central Headquarters. In a statement carried by Press TV, spokesperson Ebrahim Zolfaghari said control of the strait had returned to its previous state because the United States continued its naval blockade of Iranian shipping and ports. The statement said the strait would remain under severe control until the United States ended restrictions on vessels linked to Iran.

The security event moved beyond statements. AP reported that the United Kingdom Maritime Trade Operations center said two IRGC gunboats opened fire on a tanker transiting the Strait of Hormuz on Saturday. AP said the tanker and crew were reported safe, while TankerTrackers.com reported vessels turning around, including an Indian-flagged supertanker.

The market stake is unusually concentrated. A Congressional Research Service report says roughly 20 million barrels per day of crude oil and petroleum products moved through Hormuz in 2024, equal to about 27% of global maritime oil trade and roughly 20% of world petroleum liquids consumption. The same CRS report puts available Saudi and UAE bypass-pipeline capacity at about 2.6 million barrels per day, far below normal strait flows.

For investors, the next data points are not corporate guidance but shipping and diplomacy. Watch UKMTO incident notices, tanker rerouting data, Brent and refined-product spreads when futures reopen, and whether U.S.-Iran talks proceed before the April 22 ceasefire deadline. The CNBC RSS item captured the breaking closure headline; the primary Iranian statement and AP's UKMTO-sourced tanker report frame the immediate risk.

Not investment advice. Verify all figures with primary sources before acting.