In brief
Polymarket traders put only a 6.5% probability that the Strait of Hormuz sees normal ship traffic (≥60 daily transits) by September 30, 2026. Recent news confirms the U.S.-Iran stalemate continues, a ship was attacked transiting the strait on August 18, and ceasefire negotiations have expired without extension. Our analysis aligns with the market: we assign 95% probability to 'No.'
Introduction
The Strait of Hormuz, a critical chokepoint for about one-fifth of the world’s traded oil, has been effectively closed since the U.S.-Israel attack on Iran on February 28, 2026. A Polymarket event asks: will the IMF Portwatch 7-day moving average of transit calls reach at least 60 by September 30? As of August 19, 2026, with just over six weeks left, the market strongly favors a 'No' outcome. This article examines the key factors, market data, and risks surrounding this prediction.
What to know
The event depends on IMF Portwatch's 7-day moving average of transit calls (including container, dry bulk, roll-on/roll-off, general cargo, and tanker ships). Pre-war, the strait saw over 100 ships daily; currently, traffic is 'nowhere near' that level according to NBC News tracking. A brief pickup in early August has since reversed.
On August 18, 2026, a ship was attacked during transit, and no environmental damage was reported. The same day, AP reported that President Trump said the US has no talks planned with Iran. Meanwhile, the 60-day negotiation period with Iran has expired, as noted by CBS News, leaving the US and Iran in a stalemate. Iran continues to hold separate talks with Oman, but a joint statement is only being 'finalized' (Bozeman Daily Chronicle).
Earlier reports in early August suggested a potential deal between Iran and Oman that would allow limited shipping under Iranian control (NYT, Axios). However, that has not materialized, and the Eurasia Group now expects de-escalation only by year-end, not by September.
Chinese state shippers are deploying oil tankers outside the Gulf to avoid chokepoints, indicating expectations of prolonged disruption. The UN also confirmed that trade flows from Hormuz-dependent economies are severely hit (UN News).
The market numbers
| Outcome | Polymarket Probability |
|---|---|
| Yes (≥60 daily transits by Sept 30) | 6.5% |
| No (<60 daily transits by Sept 30) | 93.5% |
Source: Polymarket event page. Data as of analysis date.
The factors at play
- No diplomatic progress: The U.S. and Iran have no talks planned, and the ceasefire expired without extension.
- Active military conflict: A ship was attacked on Aug 18, and the U.S. maintains a blockade of Iranian shipping.
- Iran-Oman talks slow: Despite months of negotiations, only a preliminary joint statement is being finalized; no operational reopening agreement.
- Shipping industry response: Chinese tankers are avoiding the strait, reflecting long-term risk perception.
- Time constraint: Only 42 days remain until the resolution date; even if a deal were signed tomorrow, clearing mines and restoring traffic to 60/day is highly unlikely in that timeframe.
Our prediction
According to our analysis, the most likely outcome is No. Polymarket currently assigns a probability of 93.5%, while our internal estimate is 95%. The difference stems from our assessment that the combination of a stalled diplomatic track, ongoing attacks, and very limited time makes a recovery to 60 daily transits by September 30 virtually impossible. The market already prices this accurately, but we see even less room for a sudden breakthrough.
Risks and uncertainties
- A surprise agreement: If the U.S. and Iran reach an interim deal in the next two weeks, traffic could spike quickly. However, this is contradicted by Trump's statement on no talks.
- Data revision: IMF Portwatch may retroactively revise data, potentially pushing a value above 60, though this is rare.
- Unilateral reopening: The U.S. could attempt to force the strait open militarily, but current blockade operations suggest otherwise.
- Omani-led deal: Iran and Oman could finalize their agreement and immediately allow partial traffic, but this appears weeks away.
Conclusion
The Strait of Hormuz remains effectively closed due to the ongoing U.S.-Iran conflict. With no diplomatic breakthrough, a fresh attack on shipping, and just six weeks remaining, the market's 93.5% 'No' probability is well justified. While a last-minute deal can never be ruled out, the evidence clearly points to continued disruption through September 30, 2026.
This content is for informational purposes only and does not constitute financial, political or investment advice, betting advice, or any operational recommendation.