Iran has declared the Strait of Hormuz closed, sending oil prices surging more than 3% in an immediate market reaction. The Strait is the world's single most important oil chokepoint, with roughly 20% of global petroleum liquids — about 17-20 million barrels per day — transiting through it daily. A genuine closure, even a partial or temporary one, would represent a severe supply shock to global energy markets.

The immediate beneficiaries are crude benchmarks (Brent and WTI), energy producers, LNG shippers, and tanker operators who are not already in affected waters. Refiners with diversified supply chains and large strategic reserve access could be more insulated, while any company reliant on Gulf export routes faces acute operational risk.

The key tension here is the credibility and duration of the closure. Iran has threatened the Strait before without following through — markets know this history. A U.S. naval response, allied intervention, or rapid back-channel diplomacy could reverse the 3% move within hours. Conversely, if the closure is enforced militarily, the supply shock could drive oil to multi-year highs and sustain energy equity outperformance for weeks.

What to watch: U.S. Fifth Fleet response, tanker diversion reports from Lloyd's of London and shipping trackers, Saudi Arabia and UAE official statements, and whether Iran physically interdicts any vessels. The first confirmed interception — or the first confirmed safe transit — is the binary that determines whether this is a durable re-rating or a faded geopolitical premium.