How the contract works
A contract on this question settles at $1 if IMF PortWatch publishes a 7-day moving average of ship arrivals in the Bab el-Mandeb Strait of 10 or fewer on any date up to 31 October 2026, and at nothing if that threshold is never reached. The price at any moment is simply the market's collective estimate of how likely that is: a contract trading at 0.30, for example, would imply traders see roughly a three-in-ten chance of the threshold being hit, not that it is guaranteed either way. Anyone holding a position can typically sell it before the 1 November 2026 resolution date, at whatever price the market is offering then, rather than waiting for settlement.
Yes17%
No83%
Probability
How the price has moved
The only pricing data available for this market is the current consensus of 19% from a single venue, Polymarket, with $200,303 in total volume traded. With no second venue to compare against and no historical range or day-over-day move reported here, the figure should be read as a snapshot of thin-to-moderate trading rather than a heavily contested consensus price. That level is consistent with a market that sees real, ongoing disruption in the Red Sea but does not see the specific bar of a near-total transit halt as the likely outcome by the end of October 2026.
Analysis
Context
Bab el-Mandeb is the narrow strait between Yemen and the Horn of Africa that connects the Red Sea to the Gulf of Aden, and it is one of the world's busiest chokepoints for container and tanker traffic heading to and from the Suez Canal. Since November 2023, Houthi forces in Yemen have fired missiles and drones at commercial vessels they associate with Israel, the US or the UK, prompting many carriers to reroute around the Cape of Good Hope instead of risking the strait.
That rerouting has already cut recorded transits well below pre-2023 levels, but it has not stopped shipping altogether. The IMF's PortWatch project, which tracks near-real-time ship arrivals using satellite and AIS tracking data, is the reference point this market uses to judge whether traffic has effectively ceased. A related market with an earlier, 15 September 2026 deadline uses the identical 10-ship threshold, giving traders an interim read on the same underlying dynamic before this one settles.
The consensus price of 19% comes from a single active venue, Polymarket, with $200,303 in total volume. That is a modest amount of capital for a geopolitical event market, which means the number reflects a comparatively thin pool of traders rather than a deep, contested price discovery process across multiple platforms. There is no second venue here to compare against, so the usual signal of cross-venue spread — agreement or disagreement between independent pools of money — is not available for this question.
The substantive case for a low probability rests on what has actually happened since Houthi attacks began. Shipping through Bab el-Mandeb dropped substantially through 2024 as insurers raised premiums and major carriers such as Maersk and CMA CGM diverted vessels around Africa, but PortWatch data has continued to record vessel arrivals throughout the disruption — reduced, not extinguished. Hitting a 7-day moving average of 10 or fewer arrivals would represent a far deeper collapse than anything recorded during the worst weeks of the crisis so far, since even sharply reduced traffic through a chokepoint this significant has tended to number in the dozens of transits per week rather than single digits.
The related market with the 15 September 2026 deadline is worth watching as a leading indicator: if that earlier question resolves No, as the current pricing environment suggests is likely, it will confirm that traffic has not collapsed to the threshold level even under recent conditions, which would tend to reinforce a low probability for the October deadline as well. Escalation risk is real and episodic — a major strike, an Iranian-Houthi coordination shift, or a collapse of any Gaza-related de-escalation could sharply cut transits for a period — but sustaining that at 10-or-fewer for the market to register a Yes is a materially higher bar than periodic attack spikes have cleared so far.
What moves the probability
Houthi attack intensity
A sustained increase in missile and drone strikes on commercial vessels would push more carriers to divert permanently, pulling recorded arrivals down. Isolated incidents have not been enough historically to collapse traffic to single digits, so the driver needs to be an intensification, not just a resumption.
Naval coalition presence
US and UK-led naval escort operations in the Red Sea and Gulf of Aden have aimed to keep some commercial traffic moving despite the threat. A withdrawal or scaling back of these patrols would remove a stabilising factor and push the probability of closure higher.
Gaza and regional ceasefire status
Houthi attacks have been explicitly linked to the Israel-Gaza conflict. A durable ceasefire or a return to open conflict changes Houthi incentives and could move transit numbers sharply in either direction.
Insurance and carrier diversion decisions
Shipping lines make route decisions based on war-risk insurance premiums as much as on the attacks themselves. Rising premiums, even without new attacks, can further reduce arrivals and push the metric closer to the threshold.
The case for
- A sharp intensification of Houthi strikes, especially against multiple vessels in a short window, could push remaining carriers to fully abandon the route.
- Collapse of any US or UK naval escort commitment would remove the main incentive still keeping some traffic moving through the strait.
- A broader regional escalation involving Iran could extend the conflict's reach and cut transits further than the attacks alone have managed so far.
- If the 15 September 2026 related market resolves Yes, it would be a strong signal that the threshold is achievable and could shift sentiment on this later deadline too.
The case against
- PortWatch data has continued to show ongoing vessel arrivals through Bab el-Mandeb even during the most intense periods of Houthi attacks since November 2023.
- Naval patrols by the US, UK and other partners have specifically aimed to preserve some level of commercial transit rather than allow a full shutdown.
- A 7-day moving average of 10 or fewer arrivals represents a far deeper collapse than any level recorded in the crisis to date, which is a high bar to clear within roughly seven weeks of the resolution window.
- Diplomatic efforts around Gaza, even if imperfect, have periodically reduced the intensity of Houthi targeting, working against a full closure.
What to watch
The related market with a 15 September 2026 deadline, using the identical 10-ship threshold, will resolve first and offers a direct read on whether the same disruption is deep enough to already meet the bar this market needs by 31 October 2026. Beyond that, watch for any escalation in Houthi attacks reported by maritime security firms, changes in US or UK naval deployment posture in the Red Sea, and shifts in the Gaza ceasefire situation, since Houthi targeting has been explicitly tied to that conflict. IMF PortWatch updates its 7-day moving average on a rolling basis, so any sustained drop toward the threshold would likely show up gradually rather than in a single data release.
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