Somewhere in the southern Red Sea, a ship passes through a strait barely twenty miles wide, and a spreadsheet at the IMF logs it. Then another. Then another. Each entry feeds a seven-day moving average that a small market on Polymarket is built entirely around. The question is brutally specific: does that average ever fall to ten or below before a given date?

For five of the deadlines, the answer is now in. March 30, April 30, May 31, June 15 and June 22 have all resolved No. The strait did not close on the contract's terms during those windows. What remains is a single meaningful leg, September 30, and the June 30 date that is functionally pinned to the floor. The market has narrowed from a full calendar of guesses to one outcome that still has any room to move.

What the contract actually measures

The Bab el-Mandeb is one of the world's chokepoints for seaborne trade, the gateway between the Red Sea and the Gulf of Aden, and the route any tanker takes to reach the Suez Canal from the south. The Bab el-Mandeb closure market on Polymarket does not ask whether the strait is dangerous, or whether shipping insurance has spiked, or whether vessels are rerouting around the Cape of Good Hope. It asks something far narrower.

The rule is mechanical. IMF PortWatch publishes a seven-day moving average of ship arrivals at the strait. If that number drops to ten or below on any single date between market creation and the listed deadline, the contract resolves Yes. If it does not, and if PortWatch publishes a value above ten through the deadline date, it resolves No. There is a fourteen-day grace window for data delays, then settlement.

That threshold matters. "Effectively closed" in the title is doing a lot of work; the real test is whether traffic collapses to a near-empty trickle, not whether it merely thins out. Plenty of disruption short of that, convoys rerouting, insurance rates climbing, partial avoidance, leaves the average comfortably above the bar. For a primer on how resolution rules like this define the whole shape of a contract, the mechanics are worth sitting with before reading anything into the price.

The near-term legs have all settled No

The March, April, May, June 15 and June 22 deadlines have come and gone, and PortWatch did not record a sub-ten weekly average across any of them. That is decided fact now, not probability. Whatever was happening to traffic through the strait over those months, it did not satisfy the contract's definition of effectively closed.

This is worth dwelling on. The market is built as a ladder, with each rung asking the same question against a later cutoff. When earlier rungs settle No, every later rung inherits the implicit message that the threshold has held so far. That does not guarantee it keeps holding. It does mean that a Yes resolution on any remaining leg requires the average to fall in the time still available, not at any point in the past.

The June 15 and June 22 deadlines have since ticked over and resolved No, exactly as their sub-one-percent prices implied. The June 30 leg is the last of the near-term dates, sitting under one percent: alive only in the strict sense that it has not yet settled, with effectively no time left for the weekly average to collapse to ten before it ticks over. The market has effectively pre-resolved it.

The September leg is the only one with any room

That leaves September 30, trading around 13.5 percent as of June 23. It is the only deadline that still carries meaningful daylight on the snapshot. With three months of runway between the snapshot and the listed date, there is at least a window in which the underlying data could change enough to trip the threshold.

The price is not a forecast in any clean sense, and at this level it should not be read as one. It is the cost of a contract that pays out only if the seven-day average dips to ten or below at some point before the end of September. That is a high bar from any starting point above it, and the further from the threshold the data sits, the more dramatic the collapse required.

The usefulness of the contract, at this stage, is less about the level and more about the structure. It is a clean, single-variable instrument tied to one published number. Traders can argue about geopolitics for hours; the contract only cares what PortWatch prints. If you want a worked example of how prediction market prices translate into implied probability, this market is unusually unambiguous, because the resolution criterion is a single threshold against a single dataset.

What is left to watch

The interesting question for the next three months is not whether the September leg deserves a particular price. It is whether anything in the underlying data, traffic counts, rerouting decisions, the published moving average, moves close enough to ten to make the question live rather than theoretical. The earlier legs settling No without triggering tell you the threshold has been a stiff one. That is the starting point.

iPredicta tracks resolution-mechanics-driven contracts like this across Polymarket and the regulated US venues, because the markets that pay out on a single published number tend to be the cleanest place to think through how an event would actually be measured rather than narrated. The Bab el-Mandeb contract is a tidy example: most of the calendar has already settled, one leg still has runway, and the rule book is unambiguous about what would have to happen for that to change.

Frequently asked questions

What does it take for this Polymarket contract to resolve Yes?

IMF PortWatch has to publish a seven-day moving average of ship arrivals at the Bab el-Mandeb of ten or fewer on any date before the leg's deadline. A single qualifying print is enough to settle the leg Yes. Disruption that falls short of that threshold, even significant disruption, does not count.

Why have the earlier legs already resolved No?

Each of those deadlines, from March through June 22, has passed without PortWatch publishing a seven-day moving average at or below ten. Once the listed date is in the past and no qualifying value has appeared (within the contract's fourteen-day grace window), the contract settles No. Those outcomes are now decided fact rather than open probabilities.