Polymarket has Hormuz closure at 76% by March 31. I'm at 48%. The gap is a specific claim about what Iran understands about its own leverage. I think the market is conflating desperation with strategic irrationality. Those are not the same thing.
Before the February 28 strikes, Hormuz closure markets sat below 40% despite years of Iranian threats. Since the strikes, the market has moved from 40% to 64% to 76% in five days. Brent moved from $73 to $82.63 over the same period. These are not independent numbers.
The market thesis is coherent: Iran has been struck hard, Kharg Island is offline, the nuclear program is destroyed, the succession is in crisis. A cornered actor deploys its last remaining leverage. The Strait is that leverage. 76% says: Iran will use it.
My thesis: using it destroys it.
Iran has threatened to close the Strait of Hormuz in every major confrontation since 1987. The Iran-Iraq tanker war. The 2011-2012 sanctions escalation. The 2019 tanker attacks. Every US naval buildup in the Gulf. The threat has been deployed dozens of times, in speeches, in military exercises, in diplomatic cables. The Strait has never been closed.
This is not a coincidence. It is strategy. The threat works precisely because it is never executed. The moment Iran closes the Strait, two things happen simultaneously. The US 5th Fleet — already in position — begins reopening operations. And Iran loses the one asymmetric card that has deterred deeper military engagement for four decades.
The Strait is 21 miles wide at its narrowest point. Iran can mine it, harass tankers, attack shipping with anti-ship missiles, or declare a naval exclusion zone. None of these are easy to reopen — but none of them take longer than days to weeks with US naval dominance fully engaged. The 5th Fleet is not a theoretical counterweight. It is physically present.
An Iranian closure that lasts 72 hours and is forcibly reopened achieves nothing except demonstrating that Iran cannot hold the Strait against a committed adversary. That is a strategic loss larger than any tactical gain from the disruption.
Iran's oil exports have collapsed. Kharg Island handled roughly 1.7 million barrels per day before February 28. It is now processing something in the range of 100,000 barrels per day — and those barrels flow through alternative routes, not Hormuz. But the secondary and tertiary economic activity that remains in Iran — what little trade exists, the informal import channels, the humanitarian corridors — those run through Hormuz.
More importantly: Iran's regional partners — including the networks that supply food, medicine, and manufactured goods through Persian Gulf ports — depend on Hormuz traffic. Closing the Strait doesn't only hurt Western oil consumers. It hurts Iranian civilians and the supply chains that keep what remains of the Iranian economy functioning.
Saudi Arabia and the UAE export 6-7 million barrels per day through Hormuz. Qatar's LNG. Kuwait's crude. If Iran disrupts Hormuz, it invites retaliatory military action from Gulf states that have so far stayed partially restrained. This is not a move that weakens Iran's enemies. It unites them.
Whoever takes over from Khamenei — and I now give Mojtaba Khamenei 60% odds, up from my earlier 45%, given the Assembly of Experts dynamics — faces a consolidation problem. A new Supreme Leader's first weeks are about demonstrating institutional continuity and absorbing the loyalty networks of the previous leadership. That requires stability.
Closing Hormuz in week one of a new Supreme Leader's tenure would be an extraordinary escalation that makes the consolidation problem harder, not easier. It invites immediate massive US military response. It removes the last major deterrence asset. It signals to the internal factions that the new leadership cannot calculate costs and benefits.
The succession crisis is an argument against escalation, not for it. The IRGC is managing two simultaneous crises: succession and war. The organizational bandwidth for a third major operation — one with irreversible strategic consequences — is not there.
I'm not at 48% because I think Iran is rational in some abstract game-theoretic sense. I'm at 48% because the cost-benefit analysis is so clearly negative that even a degraded, partially irrational actor would need a specific breakdown in decision-making to execute.
What would move me up substantially:
A splinter faction within the IRGC that decides to force the issue — not as a strategic calculation but as a final act of defiance or resistance. The Islamic Republic has survived 47 years partly through institutional cohesion. If that cohesion fractures in the succession transition, the calculation changes.
A new Supreme Leader who has no institutional memory of why the threat works better than the action. Mojtaba Khamenei is younger, less experienced in the calculations that kept his father's government from crossing this line. That's a real risk factor.
A US or Israeli operation that directly threatens IRGC command infrastructure in a way that makes the closure feel like the only remaining response option. If the military situation deteriorates dramatically before April 1, the calculus changes.
The commodity market is not fully coherent with the prediction market. If Hormuz closure has 76% probability within 27 days, and a meaningful disruption would push Brent above $100 (conservatively), the expected value of Brent incorporates that risk. Working backward from $82.63:
At $82.63, the oil market is pricing roughly 40-50% closure probability — consistent with my estimate, not the prediction market's 76%. This doesn't mean the oil market is right and the prediction market is wrong. But the divergence is information. Brent traders have real money on the outcome. So do Polymarket traders, but in a different structure with different information asymmetries.
My read: the prediction market is capturing fear and narrative momentum. The commodity market is capturing the actual expected disruption duration and probability, net of response scenarios. The oil market's 45-50% implicit estimate feels more calibrated to me.
I'm at 48% for Hormuz closure by April 1. I updated from 35% when the market moved to 76% and Brent moved to $82.63. The update reflects real new information: Brent's movement signals the commodity market is pricing meaningful disruption risk. But I stayed 28 points below the prediction market because the strategic logic against closure hasn't changed.
Iran is desperate. Desperate actors make mistakes. But closing Hormuz is not a mistake Iran makes accidentally — it requires deliberate choice, military coordination, and a willingness to absorb the consequences. The consequences include losing the strait to US reopening operations and permanently destroying the deterrence value of the threat.
I think 48% is approximately right. The market at 76% is pricing a world where Iran's desperation overrides its strategic self-interest. I think Iran's strategic self-interest is durable enough to survive even this crisis.
One of us will be wrong by April 1.